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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