Monday, 15 December 2014


Out of the laurel forest

Last Christmas I wrote about our native mistletoe and observed that mistletoes were represented in many different families worldwide. By contrast there are 500 hollies which are all classified in an ancient genus called Ilex which is the sole member of the family Aquifoliaceae. 

On a worldwide evolutionary time scale the genus Ilex is thought to have evolved and survived in wet zones called laurel forest. Such areas are typified by semi tropical cloud forest and characterised by regular rainfall, heavy mists and dews. Many different genera of evergreen plants have evolved in such conditions and their leaves very efficiently shed water. Parallel evolutionary strategies have led to hard, waxy, glossy, slightly elongated, sometimes hanging leaves. Holly is a prime example of leaves with a pointed drip tip that directs water to the ground. 
I had no sooner penned the above and Peter came around. In my first draft I had stated that constantly wet leaves have trouble with transpiration, Wiki had just told me!
He quickly debunked this notion and went on to explain that thick shiny leaves are much more significant for survival in dry dehydrating winds and added that holly was frequently found in cold windy exposed situations. My final protestation was to ask about the drip tip? He suggested that rather than remove excessive water it was perhaps more important to conserve water from misty-wet leaves by directing it to the roots!

Holly in olden times

The European Holly Ilex aquifolium is one of our few genuinely native evergreen hardwood  trees. It has a long history entwined in ancient pagan traditions and land usage. 
It was used as animal fodder and is highly nutritious. It was extensively planted for hedging and an old country saying is that the best place for lambing is under its cover. The siting of  200 year old hollies even now is taken as evidence of old boundaries.

ees ane olde hoa’se......
He salle be putt into the parke holyne for to gnawe
old English  C14 saying

Holly as animal fodder

Ilex aquifolium ferox is rather prickly!
You may protest that hollies are rather prickly for eating! Holly when browsed is spinescent. That is prickly new growth is promoted when leaves are eaten. Holly, free of poisonous berries, were cropped high on the bush where the leaves are smooth.
There is some evidence that shoots several weeks old are preferred by farm animals. Indeed, deer and New Forest ponies have been observed to gnaw away small branches, let them fall to the ground and some weeks later to return to eat them.

Cathi’s Soay sheep came running
When I pruned Cathi’s holly and fed branches to her Soay sheep they came running and had a quick nibble before turning away as they do when they sample any new food. Now a month later those branches have been gnawed almost completely away. Yesterday I gave them some more of the original prunings and they eagerly started to eat them. Were they now confident that the the food was safe?  And do animals  find ‘weathered’ shoots taste better, perhaps sensing that natural toxins have broken down?

Holly once was even planted as coppice as an ongoing crop.  Many English country place-names with derivations of ‘hollins’ record an ancient farming history.

Holly as a garden plant

Brighten a grey day
I must tell you I am addicted to variegated plants and none of my seven hollies are green. I grow them as specimen shrubs in a more or less natural shape. I am generally quite scathing of folk who topiarise their shrubs by clipping them tightly! I came very close to this myself on one of my hollies recently when I got a little carried away with my petrol hedge trimmer. Actually it looks rather nice loosely clipped!

 I have since taken the top out
Hollies make the best hedges off all, as witnessed in old farm fields. Evergreen, variegated, (if you like that sort of thing), wind proof, hardy, long lived, impenetrable, tolerant of full sun or very deep shade, easy to grow - what more do you need?
Unfortunately small plants are very vulnerable to rabbits who just love it. I found this to my cost when I planted my new garden and with surgical precision they cut my new plants to the ground. Brenda contrived little bamboo cages around their replacements! Now that my hollies are large and unprotected they suffer no damage at all.
Holly’s main disadvantage as a hedge is that it is slow to establish. Variegated ones are painfully slow! This is the downside of their tolerance of deep shade. My advice is that if you are planting a holly hedge, to plant large container grown plants, economising a little by planting them perhaps at a fairly wide 45cm apart.

Ironically, after several years, well established hollies actually grow very strongly as I know to my cost having just pruned some unwanted branches from Cathi’s tree. 

Most hollies have single sexed flowers. To get berries you need separate male and a female plants - unless you choose a hermaphrodite cultivar such as Ilex ‘Van Tol'. With seven hollies in my garden I have no problems with cross pollination although a male plant such as Ilex ‘Silver Queen’ is unable to berry! No, this is not a misprint, ‘Silver Queen’ is a male - and ‘Golden King’ is a female! Such confusion is common! What a shame breeders and botanists fail to talk!

Golden King is a lady

I grow the silver and golden variegated forms of the more commonly green ‘Van Tol’. These clones are hermaphrodite and are not very spiny.
A flower in December! And look I have inadvertently photographed holly leaf minor


Green hollies sow themselves freely and do so in shady places in my Worsbrough cemetery garden where their hard shiny leaves efficiently shed my glyphosate spray. If you are one of my very rare visitors please help yourself!

Peter has been taking semi ripe cuttings in his propagator

After four months future success is indicated as they have now callused over (nb callus does not develop into root and on some subjects can even impede root emergence from deep lying tissue)

I had a holly tree in Bolton Percy which like the picture below had shoots close to the ground. I had contrived next to it a bed of raised soil. (These things happen). The wind blown branches abraded by the soil within eighteen months had rooted. A novel form of layering which illustrates their ease of rooting.

Peter’s pendulous holly has needed a little help with careful pruning. You can just make out lower shoots on the ground. I wonder if they will root? (I don’t think he will leave them).
Inspired by reading how easy they are to root I tried this November inserting some holly cuttings direct in the ground. Observe how I have wounded them by deliberately slicing. As is my wont, other than any leaves sliced away, all the leaves are intact. I have no idea how well the cuttings will root! Some of you will remember how I inserted many diverse hardwood cuttings two years ago and six months later reported their progress. I will again report my future success or failure!

I collected about eighty shoots

Half of the cuttings I deliberately wounded

Like the iceberg most of the length of the cuttings are buried and only the tips are showing. Note my rich ‘terra preta’ soil 


Hedges are clipped and shrubs too can be lightly pruned with a hedge trimmer. Better for specimen shrubs and small trees to tastefully prune in a natural way using secateurs and loppers. Or as in the earlier picture a saw!

I normally take out large pieces when I prune. I decorated our courtyard for Christmas with some of my surplus prunings

And then added a few crab apples for the blackbirds

This Ilex ‘Van Tol’ was blown horizontal on the village plot several years ago. Still attached to the ground, it threw up a complete line of strong new trunks. With the aid of Peter’s chain saw we now have a very fine single trunked tree. Note all the new growth was wonderfully vigorous - in contrast to my  earlier comment about hollies after planting being so very slow.

Variegated varieties reverting

Shame on me. My Golden King has reverted green. Unusually for reverting, the  growth in this case comes from below the ground. (Such growth on shrubs is usually a rootstock suckering but my holly was not grafted).

These are my prunings - how could I have allowed such a state of affairs? Observe the pruned holly in the background
See the reverted yellow shoot. Where variegated hollies are foolishly cut back very hard to the trunk the new shoots usually revert to yellow and lack chlorophyll. Such a tree will die. 

If you are feeling Christmassy you might like to read about mistletoe and ivy.

Mistlethrushes fearlessly defend their holly or mistletoe

Sunday, 7 December 2014

Hybridity’s significance in evolution....high-lighting hybrid plants.

Part 1. 

I am above my pay-grade today! Writing about one of my passions, evolution. I am questioning Darwin’s received wisdom that life’s evolution comes down in a straight line in a continuity of small steps. Not that I suggest anything that greater minds than my own do not espouse. My source of inspiration is that great American geneticist Eugene McCarthy and if my post today interests you, you will constantly need to refer to his website to clarify the numerous ‘loose ends’ that I fear I will fail to tie.
Don’t get me wrong, the fact that life has evolved slowly from primitive beginnings is a fundamental part of my personal belief system. 
The bone of contention is that although we gardeners personally experience the results of hybridisation on an everyday basis, conventional and might I say outdated ‘popular’ macro-genetic theory dismisses it as an insignificant aberration.

Let me please emphasis I do not deny the slow and gradual pace of macro-evolution, nor the accumulation of small genetic changes. What I do now believe is that when genetic changes are shared from one organism to another and when a huge number of genes are transferred and recombined and expressed in novel combinations, the contributions of hybridity to evolution is a very powerful force indeed.

Some adherents of hybridity theory  suggest that Darwin himself who carried out hybridisation of domestic birds was well aware of it’s significance but perhaps thought the world not to be ready for it yet.

This nerine is an interspecific hybrid derived from several different species. It’s hardiness was introduced from Nerine bowdenii into otherwise tender nerine. It’s large flower spike is no doubt an example of ‘hybrid vigour’

Strawberry (Fragaria, itself an interspecific hybrid) hybridised with Marsh cinquefoil (Comarum) to create intergeneric hybrid Fragaria ‘Pink Panda’
My own Paulian conversion is an unexpected consequence of writing my blog! You can witness my enlightenment in my post ‘Musings from York’ when ‘Fool-On-A-Hill’ - perhaps it is a pseudonym? - wrote illuminating things in my comments section. Please go there, his words are more eloquent than mine. Where fools rush in angels fear to tread!

There are many popular intergeneric hybrids between Heuchera and Tiarella. Breeders create new varieties of Heucherella by repeating  the original cross or selecting nice seedlings from Heucherella.
Harry and I always argued. He would sometimes storm home and I would think it would the last I would ever see him. I would bang the table! He accepted evolution in principle but insisted there was a fundamental flaw as shown by the fossil record. Animals and plants appear without any clear immediate and obvious ancestor and remain relatively unchanged for millions of years up to their eventual extinction or to the present day. I used to insist that ‘missing links’ were constantly being filled and would argue that misinformed deniers did not recognise that when one gap in the record was filled, two others were created.
After extensive reading I am now convinced Harry was right and that the fossil record does show a punctuated progression. How we miss him and I wish I could just pop round and tell him!

Some general observations about evolution

Before I get my teeth into the hybridity thing there are a few things about evolution that I think gardeners might misunderstand. And perhaps I do too! Very often the press records examples of rapid evolution such as the change in the colours of moth wings or very recently the height that bats nest in their caves under the threat of a competitive alien bat species. I wrote myself how natural selection of plants growing near polluting former Welsh lead mines had over very few generations developed the ability to survive and thrive despite toxic heavy metals. 
None of these changes require new mutations but only the diversity which already exist in the ordinary variability of the population.

Such rapid change in contrast to stability of complete organisms over perhaps millions of years. 

Nearer to my theme is when hospital bacteria develop resistance to antibiotics. It is widely and accurately reported that the spread of this resistance is a more acute danger because different species of bacteria can exchange new genetic data. Resistance developed as a consequence of for example, overuse of an antibiotic  in agriculture, is passed on to other bacteria by a process of conjugation. Not quite hybridity but the result is in some ways similar. When genetic information is passed from species to species it is a very powerful force of evolution indeed.

Some general observations of hybridity

“I’m not a mongrel but this wretched streptocarpus has multiple parents”
“Poppy, I have serious doubts about your origin but the text book agrees with you”

When I sit here in our conservatory today I see numerous plants such as my calamondin orange, fuchsia, and pelargonium that are known acknowledged hybrids between two or multiple species. I also see orchids and christmas cacti and hippeastrelia which are hybrids between distinct genera. In gardening terms hybrids are very common and indeed almost all of our modern garden plants are the result of many years of selective breeding where genetic information has been mined from a huge range of distinct albeit (usually)related plants.

The Christmas cactus has parents from several genera. In my post about this plant I mentioned it is ‘invading’ the wild in South America. Should we worry or just admire evolution?

Inter specific hybrid calomondin’s several citrus sources are said to be ‘lost in antiquity’

It is sometimes suggested hybrids are less fertile than ‘pure breeding species’
I had no trouble germinating my calomondin pips.
Hybridisation within an established species is an everyday occurrence to  plant breeders and seedsmen. Gardeners routinely sow F1 hybrids where two closely related parents have been crossed by the seedsman ‘on demand’. Even the small differences between such close relatives produce hybrid vigour. How much more vigour and variation there will be when whole chromosomes containing thousands of new genes combine when species cross.

Compact Winter-flowering Corydalis elata has been crossed with taller June-flowering Corydalis flexuosa to produce several named hybrids such as Corydalis ‘Spinners’.
My hybrid is intermediate in size between it’s parents — a common characteristic of hybrids — and flowers at the same time as elata. 
As a bonus many of my hybrid plants continue flowering for the rest of the Summer.This picture is in early December! Surely an example of hybrid vigour?

Wolves, coyotes and dogs

All are different species of the genus Canis, share the same chromosome number (78) and interspecifically hybridize relatively freely. Not in everyday terms, but on an evolutionary time scale not uncommon.
I had not intended to say very much about animals today but have been drawn to two recent news items. One was about coyote-wolf hybrids causing concern in north east America.The other - no lesser source than the Daily Mail(!) - reported real research that challenges the conventional view that dogs are descended from grey wolves.

On reading further about coyote/wolf hybridisation I found that it is not a new phenomenon and genome studies and actual recordings show it has taken place hundreds and perhaps thousands of times over, say, the last hundred years. The coyote genome seemingly contains genes from grey, red and eastern wolves. It is a magnificent coyote/wolf mixture.

As is normal with hybridisation events, a new hybrid usually merges into the species of one of it’s parents by repeated backcrossing. All over America there are slightly differing ‘strains’ of coyote that further intermingle as they migrate. Hybridisation has given natural selection opportunity to work with an increased library of genes to create the superb cocktail that proudly fulfils a ‘top predator role’ in the USA.

A caveat here. In nature rare hybridisation normally take place where the ranges of plant or animal geographical distribution overlap. In most cases repeated backcrossing within the population of one of the parents reduce ‘new genes’ to barely perceptible levels. A population’s integrity is often maintained for thousands of years. In most places coyotes may carry very few ‘wolf genes’ and many of my American friends might argue that in their locality there are none!

Some coyotes, dubbed ‘coy-wolves’ contain more wolf genes than ‘their own’. Talk about ‘a wolf in sheep’s clothing’!

The new data on domestic dogs  is that they have not evolved from the grey wolf as previously thought, but from a slightly earlier and now extinct wolf-like common-ancestor. Dogs as a distinct animal have been around much longer than previously thought. The picture is clouded, in that, since dog’s domestication, dogs and grey wolves have sometimes bred with each other.

In evolutionary terms, thousands of years is relatively recent. On that small timescale canid hybridisation has had significant impacts on their own evolution. 
Why does conventional theory assume that hybridisation has not been happening for all of millions of years?

I must confess to a small difficulty in understanding what hybridity really is! The division of organisms into families, genera, species (and subspecies, varieties, cultivars and all) is a man made artificial construct. What really is the difference between sharing new genes by intra species mating to inter-species, inter-genus and inter-family crossing? Yes I know that usually within a species there is simple pairing of genes via the process of meiosis and that between more distant parents the crossing of information to form a new genome is sometimes at first a more messy process and that most crosses fail or are infertile (but not all). To me it seems that from the closest of liaisons to the more distant successful couplings, in all cases genetic information is shared.

This is the first of three posts on this subject - the next in January

Friday, 28 November 2014

Controlling weeds in grass and rough places

MCPA and other chemicals used in grass.

I take a break from glyphosate today but find it even more necessary than usual to advice inexperienced gardeners to be extremely cautious and to read my previous posts about spraying. You can find my posts by inserting ‘glyphosate’ in the search box at the end of the blog scroll.

MCPA has been safely used on amateur gardeners' lawns for more than fifty years. It is an ingredient in many of the popular three-in-one mixtures of lawn fertiliser, moss killer and weed killer. It is also used in amateur and professional lawn weed killer sprays mixed with equally traditional choices such as 24-D and mecoprop (clover killer). Modern alternatives such as triclopyr are also available.

Unfortunately I am unable to source an amateur spray that is MCPA only! Inconvenient for my suggestions today. However at the press of a button on your computer you can find a professional formulation marketed as Agritox. 
Other than glyphosate I am generally reluctant to recommend professional chemicals to the public. Many are too dangerous and they are invariably much more concentrated than amateur versions.The liquid concentrate of MCPA is an eye irritant.
Depending on your domicile the use of professional products might even be illegal. In the UK, chemical producers and garden centres maintain that perception. I write for trained professionals as well as home gardeners and try to cater for the needs of managing large areas. If you do use commercial products please remember that their strength when diluted and applied to the plants is exactly the same as when they are from amateur sources.

Another reservation about lawn weed killers such as MCPA is that they have a bad name because they have frequently been used irresponsibly by farmers, government and local authorities and various organisations to kill wild flowers when regarding them as weeds. Things are better now, the last time I walked round Kew, the daisies and other wild flowers in the grassland areas were an important part of the landscape.
I argue that the resources of gardeners, landowners and farmers can be used for good or bad. Even innocuous practices such as ploughing or drainage when ill-used can destroy natural environments. No one would argue that, for example planting trees was not a good thing. But, if you were to plant Leyland cypresses in the wrong place, or to plant trees in rich water meadows that were filled with wild flowers, or place mono-cultures of holly in suburban places or trees obscuring beautiful views it might not be wise.

If you go to the RHS website you will find products available to amateurs for use in grass.The only 'straight' spray I could  find (rather than ‘cocktails’ ) was triclopyr which against woody weeds such as young saplings or even 'difficult' ivy is better than MCPA. I would go so far as to suggest that against woody weeds triclopyr is the best weedkiller of all. The RHS state that triclopyr is only suitable in coarse grass and not on fine lawns. This may be true but when I have used it myself at low concentrations on my fescue lawn, coarse grass is slightly and very temporarily browned and my fine fescue is competely untouched. Unfortunately many gardeners have more coarse grasses in their lawns than fine ones!

Properties of MCPA and similar grassland alternatives

Well mainly it does not kill grass - when suitably diluted!

Like glyphosate (which most definitely does kill grass) it is translocated and when absorbed by the foliage, moves to the roots and kills the whole plant. Although MCPA is degraded by soil bacteria, unlike speedier glyphosate it takes several days. This is an advantage in lawns because it continues to kill broad leaved weeds but is rather less of an advantage when mowings contaminate the compost heap. 
And of course unlike glyphosate, it would be fatal to sow seed or plant delicate young plants for a few weeks after MCPA's use.

If you spray grassland after using glyphosate it is very important to wash out your sprayer! Spray the tank and its diaphragm completely empty and spray through with clear water. If not you will have several square metres of dead grass!

Against woody weeds such as brambles, MCPA (or even better triclopyr) are superior to glyphosate. Even herbaceous weeds such as nettles, docks and dandelions are arguably more efficiently killed by MCPA than by glyphosate and certainly more quickly!
If it rains heavily after these grassland weed killers are used, unlike glyphosate, they will still be effective. 

Of course only an idiot would spray MCPA and similar grassland herbicides amongst ornamental plants. That idiot is sometimes me!

Five case studies

It is not my intention today to discuss weed control on lawns. There is plenty of that in the popular press, most of it sound, although I could never understand why they  sometimes tell you that September and October is too late to apply lawn herbicides. I spray even in November! It is October when I seem to have my greatest need!

Case 1. Killing brambles at Worsbrough

Twenty years ago when I took on the weed and plant management of the old three acre cemetery, two acres were under five foot high brambles.
I did not originally intend to take on such a large area, but I had three months of unexpected help from the ‘boys’ from the probation service and the brambles were all strimmed to the ground. I would rather start by spraying intact plants but entry into the thicket would have been a shear impossibility. 
The point of the story is that the regenerating brambles were sprayed alternately with glyphosate and MCPA. Please don’t ask me whether one is permitted to mix them together!
It took almost two seasons to completely eliminate the brambles before I could attempt to establish my flowers.

In a similar case when I took on Seaton Ross village plot which was almost a monoculture of three foot high ground elder I used the same combination.

Case 2. Peter’s fields in Toulouse 

Brenda’s son lives in a shabby-chic manoir in France. Like many unwanted French properties it has many acres of grounds. Peter’s two horses graze several fields which when they moved in were overgrown with brambles, nettles and in one field numerous ash saplings. My regular ‘holidays’ would start every morning by emptying a large knapsack sprayer charged with 24-D or Grazon 90.
24-D is more readily available than MCPA in France and is an equal equivalent. Grazon - get the accurate pun in the name - is a superb grassland cocktail that contains triclopyr. and will take out very ‘difficult’ weeds.
I made considerable inroads in the first two years of our holiday time visits. These were as nothing when Peter acquired a tractor mounted powerful mower that after a year had completely shifted all the ‘woody weeds’. Leaving  a few nettles for me!

Case 3. Cathi’s paddock and outbuildings

Cathi has rare breed hens, rheas and soay sheep on her smallholding. Harry used to spot-spray nettles, sedges, brambles and creeping thistle on the three acres. (The sedges needed glyphosate which of course also kills surrounding grass if you are not very accurate). I have taken on the mantle and once a year break off from the fields to use the same dilution of MCPA to spray the buttercups and plantains in her acre lawn. My usual dilution of MCPA is one in 70 concentrate/water ratio of Agritox (elsewhere against epilobium one in 50). MCPA does not kill Cathi’s wanted nitrogen fixing clover!
No nettles or brambles now survive around her outbuildings and sheds but that most wretched of weeds epilobium keeps seeding back and is duly zapped.

Case 4. On a country estate
At one time my ‘practical’ consultancy took me to work in a place renowned for its wild flowers. Unfortunately even in such places hogweed, nettles, brambles and other coarse plants infiltrated the beauty. Such ‘nasties’ (the owner’s description) were taken out by spot spraying with MCPA. 
Peter’s beautiful bluebells reprinted from my previous post might just might have had similar ‘help’. 

Case 5 Maintenance of Worsbrough cemetery 2014
Fragaria ‘Pink Panda’ brightens up my November morning but is very sensitive to both glyphosate or MCPA so I carefully avoid it!
At over three acres it really is too big for me! I only have opportunity and energy for one four hour visit per month. This labour input is way below any normal amount for large areas of thousands of flowers! Never-the-less some people think it takes care of itself! 
I only get completely round with my sprayer every two months - and in the more wooded and unvisited parts even less. It is not enough!

I have by now got rid of all established perennials weeds save perhaps for that impossible weed called hedge vetch which at least looks rather pretty and does not invade new patches. Most seeding weeds are almost completely eliminated. The exception is that wretch, epilobium, which not only prolifically seeds all over, but when I do get rid of it, it blows in again from outside. Although glyphosate kills it in summer when it is growing - and seeding - it is too late. It is a perennial that dies back to a tight green rosette of leaves for six months or so overwinter. Unlike glyphosate, MCPA does kill it at this phase. Not selectively of course and the spray needs to be directed.
I have developed a technique where my herbaceous perennials and self seeding annuals are in large drifts and clumps. My shrubs are vigorous and large and generally hug the ground. My plants do much of the work of suppressing germinating weeds.

This leaves large spaces which are empty of wanted vegetation. I spray the epilobiums there with MCPA!
It is of course potentially damaging to neighbouring delicate plants and I am highly attuned to what is sensible!

I had intended to tell you more about these methods but got cold feet and decided it unwise to lead you into such sin.
Instead I am providing pictures of my last visit to Worsbrough in mid November when I sprayed MCPA! 

As the photos were taken in mid November it’s not very pretty!

This is the culprit
The epilobium rosette has already seeded - and for the picture I have pulled off the stalk. I won’t spray the foxglove
Epilobium seedlings

Helleborus seedlings have plenty room to self sow and if there are too many they are reclassified as weeds! 
Prized Briza maxima freely self seeds but the locals think it a weed, as I do here where I have rescued my cyclamen with carefully directed glyphosate
You can see why some think the ornamental grass briza is weedy and of course MCPA does not kill  grass when I carefully spray round the polygonum 

There are a few small stands of un-mown  fescue grass that I have over the years allowed to remain having eliminated coarse grass with carefully directed glyphosate. I can take out broad leafed leaved weeds by spraying with MCPA  Many monocotyledons such as  sisyrinchium are undamaged as long as I do not spray the leaves
A similar area where the blue ornamental grass is also resistant to MCPA. The huge impenetrable clump of forsythia takes care of itself. I wonder how many decades ago someone planted a forsythia on a grave

 I could not kill this even if I wanted to!
(ivy needs several strong sprays to kill it and it is usually best if you just pull it out!)
Several patches are completely smothered with the poached egg plant where seedling weeds have little chance to establish. Although sensitive to glyphosate or MCPA when this annual dies down in August it is a good chance to spray any invader.
No problems with MCPA on a mossy path, nor under a self sown pine.

No one ever sees insignificant collateral damage in places like this.

Whoops I have missed a bramble. I will very carefully spray it with MCPA - but I can only do this because the phlox is dormant

All my clumps start very small and take several years to make large ones! I am very patient with the plants I pop in from my  own garden!

Some roses are very sensitive to MCPA but not this one
In Spring I have tens of thousands of snowdrops and bluebells and thousands of daffodils. I of course do not spray the foliage, but have never found them to be damaged when spraying with MCPA when they are dormant.

When I eventually stop spraying the cemetery will again return to brambles

Yesterday I updated my post on Japanese knotweed 

Wednesday, 19 November 2014

The unnatural gardener

Another fine article from Peter Williams

I wrote about Peter’s wonderful garden last year. I also published his own article about rhododendrons which he had previously written for the local Beverley based coven of the Hardy Plant Society of which he is a member and regularly attends their fine lectures. Not to mention his own!
This year I persuaded him to go the whole hog and submit his new article to the ‘Hardy Plant’! What a fine name for a wonderful magazine published twice yearly by the Hardy Plant Society - of which I am also a member. Members of the National groups and /or local groups are keen knowledgeable gardeners. The articles in the Hardy Plant are written by real gardeners both amateur and professional. A cut above the usual gardening press.

Don’t let me put you off  - new gardeners are well represented in their ranks  - and experienced gardeners are only too pleased to share their skills. Please join and also enrich your garden through their annual seed distribution!

Peter’s article has been sitting waiting on my computer for six months. It has now been published in the ‘Hardy Plant’ and I have been given the go ahead to republish. I hope you enjoy it as much as I did.

Peter Williams unashamedly confesses to unnatural gardening practices

Natural gardening and gardening with nature are currently very fashionable ideas. We are urged to embrace this philosophy with the assurance that, if we do, our gardening experience will be enhanced. It is suggested that if we would only adopt these principles, the plants and animals in our gardens would reach a new equilibrium and there would be fewer outbreaks of pests and diseases.

I didn’t really understand these principles, or how they were supposed to work at the ecological level, so I started to think around the concept. 
I quickly came to the conclusion that believing that you can garden naturally is about as sensible as believing in the tooth fairy! Now I have to say, right at the outset, that I am not a natural gardener, and I confess that many of the things I get up to in my garden can only be described as unnatural practices. Natural gardeners do exist, but they are folk who have absolutely no interest in cultivating plants or land, and simply leave their gardens to ‘go wild’ or revert to nature.
Any form of practical gardening is simply meddling with nature – and it’s great fun and brings enormous satisfaction.
This meddling with nature takes many forms and includes introducing species collected by plant hunters from all over the world, or new hybrids produced accidentally or intentionally by plant breeders. Moving plants around the globe, and searching out improved cultivars to plant in our gardens, has always been a fundamental gardening activity – although it has also been responsible for introducing some new pests and diseases that threaten many of our truly natural plant communities.
In order for our chosen plants to survive and flourish, we gardeners have to intervene on their behalf in an attempt to suspend natural processes. Such interventions include weeding, feeding, supporting, pest reduction, and changing the microclimate, sometimes to the extent of constructing glasshouses and even heating them with fossil fuels. We import/export soil and substrates; we dig and rake; we water; we spray; we lift and store tender perennials – but as long as we have nice irregular flower beds and wavy paths, we plant in drifts and we never use nasty chemicals (except of course in emergencies) we may still claim to garden naturally!
Except in an emergency
For the sake of discussion, let’s look at three aspects of natural gardening.
 Naturalistic planting
This probably means different things to different people, but my understanding is that it is an attempt to copy some features of natural areas and transplant them into our own patches. For example, over many years at Chelsea, famous nurseries like Backhouse of York and Wood of Boston Spa, created pretend Scottish Highland rock streams or mountain screes to show the landscapers’ craft and mastery of the natural world. Such exhibits started to decline in the mid 50s and were virtually extinct by the late 60s, demonstrating that what’s considered to be desirably naturalistic changes with fashion.
More recently we have seen the rise of prairie gardening, where ornamental grasses and various types of daisies are planted in broad sweeps at great density to create a colourful wilderness which reaches its peak in late summer and autumn These pretend prairies must be a godsend to nursery owners and they can look stunning in the first few years, but the difficulty of maintaining them probably means that they won’t stay in fashion for long. A number of well known prairie gardens have had to be replanted after just a few years because they became dull, weed-infested and truly natural looking!
In prairie style, monardas and heleniums are densely planted for dramatic effect and weed exclusion
Meadow gardening is another form of naturalistic gardening, and some garden meadows do resemble real meadows quite closely. The only difficulty is that even ancient meadows are not really natural and require management on a large scale, by grazing at appropriate animal densities and appropriate times of year, or by annual cutting and hay removal. In a garden situation, on a normal-size plot, it is extremely difficult to recreate a natural-looking meadow. In most cases the soil is too fertile, and the advice is usually to strip off the top 10cm of soil and start again. Even if soil fertility is suitably low, many newly created meadows where expensive wild-flower seed mixes have been sown look for a few weeks like an explosion in a paint factory – a riot of different colours from the predominantly annual species in the seed mix. Then nature intervenes and, sadly for the proud owners of these bright patchworks, the meadows never look quite ‘as good’ again unless they are re- sown.
A contrived meadow of a commercial wild flower mix gives a riot of colour that needs replanting each year
Perhaps I am guilty of taking a lowbrow, practical approach, so to redress the balance I’ll turn to Sarah Price, the current doyen of naturalistic gardeners. Ms. Price has created beautiful gardens at Chelsea and elsewhere, and has written eloquently about their creation. Thus she writes ‘plantings must have a sense of transparency. Sunlight filters through the tallest plants, through the different heights and forms; petals and grasses appear to glow from within, while the striking forms of seed heads form strong, dark silhouettes. To be surrounded by this ethereal sort of beauty is an almost transcendental experience.’

Now, while I really appreciate a beautifully designed garden or border, most of my transcendental experiences in the garden have been greatly facilitated by a glass of cold Chardonnay! However, the serious point is that talented designers like Ms Price take immense care in selecting and arranging plants so that they bear a resemblance to an idealised natural environment. The gardens may well be beautiful, desirable and give great pleasure, and that is absolutely fine, but they are no more natural than a garden with a pin-striped lawn, rows of dahlias, an African-style thatched breeze hut and a few eucalyptus trees.

Havens for wildlife
When I read gardening magazines I sometimes feel I must be failing because the main thrust of my activities is not to provide a safe haven for local wildlife. While I’m passionate about conservation and actively involved in the Wildlife Trust movement, I don’t believe that it’s the principal role of gardeners to create mini nature reserves. Gardens do provide very local habitats for wildlife, but often they’re not of real importance because they’re too small, too isolated and too transient. Sustainable nature management requires ‘more, bigger, better and joined up’ regions, as suggested by the Lawton Report, Making Space for Nature: A review of England’s Wildlife Sites and Ecological Network (2010). 

In fact I spend a disproportionate amount of time attempting to keep much of the local wildlife out of my garden. I spent the first few months of retirement attempting to rabbit and badger-proof my garden. I had a real sense of achievement when I completed the fencing and naively thought that the problem was solved. I could not understand how the occasional rabbit still got in – until the first snowfall that winter when distinctive footprints indicated a nocturnal rabbit super-highway under my front gate. I fixed this by attaching plastic clematis netting to the bottom of the gate that dragged on the gravel. At dusk a week later I spotted a tawny owl on the post near the front gate and excitedly called to my wife to come and look. When asked if she could see it, she replied, “Yes, and two rabbits on the drive”. A short period of observation revealed that rabbits could charge the plastic netting and get through! These invasion routes now closed, all I have to do is find a way to prevent squirrels and mice from eating the hardy cyclamen, crocuses and tulips that I try to naturalise in my grassed areas, and to stop deer jumping the rabbit fence to graze everything woody. I was dumbfounded to read an article in one of our leading gardening magazines which gave natural gardeners tips for attracting animals, including muntjac deer, into their gardens. John McEnroe’s famous words came to mind – “You can not be serious!”
In the garden – you must be joking

All these wonderful ‘natural scenes’ have been influenced by man
Of course the animals that we should help are the birds, bees and other insects; or, more precisely, some of the birds and bees. Bees of all sorts are welcome, as are many bugs – lacewings and ladybirds (except of course the new foreign invader, the harlequin), and butterflies, so long as their caterpillars eat someone else’s plants or stay on the small wild patch that we have set aside. Lily beetles, vine weevils, and slugs and snails give some of us nightmares, so obviously they are not included in our invitation to cohabit in our gardens
This predator is welcome –as long it is not a harlequin ladybird
Birds are welcome of course, except certainly pigeons, probably magpies, and possibly sparrow hawks. On a recent garden visit I was talking to the owner of a lovely garden when a sparrow hawk flew through. I was delighted to see such a magnificent creature, but the owner got very angry and explained that she only wanted little birds in her garden, and she resented spending a lot of money buying bird food only for some of the small birds to be eaten by a hawk. I tried to suggest that the sparrow hawk was only doing what sparrow hawks naturally do, and that its presence indicated a healthy ecosystem, but the owner was un- convinced. She was equally unconvinced when I suggested that gardeners’ cats eat far more birds than sparrow hawks.

Robins and long- tailed tits are always welcome, but is a sparrow hawk undesirable or an indicator of a healthy ecosystem?
Organic practices
Natural gardeners refrain from using unnatural ‘chemicals’ in the garden and would certainly not use pesticides or herbicides. I can totally understand their sentiments – few people would want to use toxic chemicals on their plants, especially their food plants, without thinking about it very carefully. The problem is that sometimes it’s not possible to control pests or weeds by natural or accepted organic methods. There are no effective organic controls for lily beetle or bindweed, Japanese knotweed or couch grass and, except perhaps in the smallest garden, it’s impossible to squash all the pests or pull out all the weeds.
Biological controls are excellent in some situations, for example, curbing glasshouse whitefly with parasitic wasps; but it can be very difficult as an amateur gardener to obtain or use biological systems, for instance to control the larvae of vine weevil, while the insecticide thiacloprid (Provado) works very well. Similarly, glyphosate (Roundup) is very effective in controlling even dense areas of couch and, used carefully, is an invaluable tool.
Now from a biological point of view, poisoning your neighbour and/or protecting yourself with toxic chemicals is a very natural thing to do. Allellopathy is the ability of a plant species to excrete chemicals into the environment that inhibit the growth of competing plants. Couch grass (Elymus repens) is a classic example: its root exudates reduce the ability of competing plants to take up nutrients. Highly invasive plants like Golden Rod (Solidago canadensis) (and a hybrid Japanese knotweed (Fallopia x bohemica) have been shown to be allelopathic.
Golden Rod escaping into the Derbyshire countryside
It may come as a surprise to some natural gardeners that very many plants protect themselves chemically against grazing animals. Indeed, many of the world’s most poisonous substances are natural plant products. The alkaloid strychnine is present in the bark and seeds of the poison- nut tree Strychnos nux-vomica, native to India and adjoining regions. It is very toxic to rodents and probably plays a role in protecting the tree against rodent attack. Similarly, eucalyptus species contain powerful alkaloid toxins that protect against herbivorous marsupials. Some common insecticides are based on chemicals extracted from wild plants: thus nicotine and pyrethrin (and their slightly modified derivatives) are widely used to kill insects. Defence against insects is precisely the role these chemicals played in the wild plant. The Victorians knew that the damaged leaves of green laurel (Prunus laurocerasus) release hydrogen cyanide, so butterfly collectors placed crushed leaves in the bottom of a Kilner-type jar to kill the specimens they’d caught. The ability to produce cyanide when damaged is known as cyanogenesis and is widespread in the plant world. It occurs in white clover (Trifolium repens) and Bird’s Foot Trefoil (Lotus corniculatus), and many of the world’s most common food plants including maize, wheat and sugar cane. The amounts of hydrogen cyanide produced are not usually great, but they’re enough to deter grazing animals.
Sinigrin, the natural chemical that gives brassicas their distinctive ‘cabbagey’ smell and taste, is also a substance that is very toxic to most insects. This might come as a surprise to allotment holders who frequently see their cabbages shredded by cabbage-white caterpillars, but it shows that plants do not have it all their own way. Animals co-evolve with plants, and those that can overcome plant toxicity may have an exclusive food source. A small number of insects have become resistant to sinigrin and now use it as an attractant; for example, the cabbage white butterfly specifically seeks out leaves containing this chemical on which to lay its eggs. (The whole field of plant/animal interactions is fascinating, and relevant to gardeners: think of peonies paying ants protection money (nectar) to keep them free of aphids.)
I’m not trying to persuade you to change your gardening practices radically, but to think about the relationships between gardening and natural ecosystems. Gardening is one of the few areas of life where you can do more or less as you please, and I am encouraging you to do just that. Even experienced Hardy Planters may not be immune from the pervasive influence of television and magazine gardeners who have programmes and pages to fill. It is their remit to be ‘trendy’, no matter how impractical, and their gardens have to last only a year or two before the next fashionable planting scheme.

Don’t get stressed because your activities may not, in the current climate, be seen as ‘ecologically sound’. Do it because you enjoy it. Finally, just remember this – leave your garden unattended for three weeks and it will become untidy, leave it for three months and it is a wilderness, leave it for three years and it is a nature reserve. Now that’s really natural gardening and is exactly what I intend to do when I am too old to keep up my unnatural practices.
It takes no time at all for a garden to return to nature
Peter Williams retired from teaching aspects of plant science to mildly enthusiastic undergraduates to ‘spend more time with his plants’ and occasionally talk about them to groups of totally enthusiastic Hardy Planters.
This article was first published in the East Yorkshire Group’s newsletter.
The photographs are Peter's own and those of Harry Poole

The week after Peter’s article was published he attended a gardening seminar at Askham Bryan College organised by that other fine gardening group, The Alpine Gardening Society. He sat next to a stranger and got talking - about the Hardy Plant Society! His neighbour asked him how he liked the new format of ‘The Hardy Plant’ and went on to remark about a particularly fine article by a ‘new writer’. Peter was able to say that it was he! How nice. Peter did say that if the comment had been critical he would have stayed schtum.
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