Wednesday 28 November 2018

Magnificent michaelmas daisies

Aster novae angliae
In my youth I got a bad impression of michaelmas daisies. My parents were not gardeners. They avidly listened to Gardener’s Question Time after Sunday dinner but remembered nothing. Perhaps just as well but a chord was struck in my innocent young mind.
The michaelmas asters in their garden must have been planted by a former owner. They were the kind that you give to friends to get rid of them (the friends as well as the daisies).
They were tall and straggly and grew with some vigour swamping their neighbours. They dripped with powdery mildew and by flowering time the insipid lavender flowers were surrounded by brown or yellow dead and dying leaves. Time to cut back - the flowers were not worth keeping!
It took along time to learn to love what is now one of my favourite plants.

Symphyotrichum novi belgii  The New York Aster

Symphyotrichum novae angliae The New England Aster
As is my want I scanned a few references before writing this post. To my horror I found the botanists had been at them and changed most of their names. No longer are they asters. A website gardener gallantly declared they were rather nice names. Symphyotrichum and Eurybia. I don’t really think so. They will always be Michaelmas asters to me

Eurybia - lovely plant, ugly name

The problem of powdery mildew

A month after purchase from garden centre
This air born fungus disease has long been the scourge of Michaelmas  daisies. Less so now with resistant new varieties and recognition that certain species such as Aster novae angliae and Aster amellus are completely resistant.

Many novi belgii varieties are still very susceptible and in principle might have done very badly in this severe drought year. Fortunately this has not my been my own personal experience. I wonder how readers faired? Heavy Autumn rains in some areas might have come to the rescue.

Circumstances  predisposing to powdery mildew

My purple novae belgii is completely resistant
It's in dry conditions when plants suffer moisture stress. It seems to me to be almost invariably where aggressive water seeking roots of trees and hedges dehydrate the soil
Trees and shrubs are also offenders in that shaded leaves of the daisies stay wet with dew or light rain much longer than plants in open positions. In these conditions fungus spores germinate and thrive.
As a triple whammy trees and shrubs create shade. Most Michaelmas daisies need full light - such plants have more resource to fight mildew

Yuk, a misshapen mildew prone garden centre plant I had overlooked throwing away
You might correctly conclude that your daisies need an open position in moist (but well drained) soil rather like the water meadows where many of their ancestors come from.

So why have my Michaelmas daisies thrived in this very dry Summer

On this variety even the seed heads are lovely
All are mildew resistant varieties, are in full light and grow in my sandy/silt soil and of course are never sprayed. In Spring after excessive rain the soil was at maximum water holding capacity. I constantly despaired when in the following five months we only received a miserly six inch of rain. Fortunately most of this came on just three separate spaced out occasions and penetrated more deeply than repeated light showers - the latter so conducive to fungal spores. 
My topsoil gives way to a two metre layer of pure coarse silt/fine sand. I think my daisy roots just kept going down and finding water.
Most of my daises are the  novae angliae kinds and  other than Aster amellus none have been watered. They have just loved the sunshine and thrived. To my surprise my two novi belgiis have done equally well.

Cultural notes

As you might guess my daisies are not staked even though some of the novae angliae kinds are six foot high. Some are a little uneven but that is my way. 

Even the most ardent staker would not put sticks in Purple Dome
I am also unorthodox in that when I plant herbaceous perennials they stay in forever. No labour intensive quadrennial transplanting for me. Some of my daisies have been in place fourteen years now.

For propagation most michaelmas daisies can be divided and transplanted at any time - even in Summer if you cut back the tops. 

Aster amellus is one exception and really is quite fussy - best early May or very early Autumn (still in flower) and never in Winter.

I divided these Aster amellus this September

Readers will know mine is a glyphosate garden and most of my weed control is done by this wonderful herbicide. Exceptionally Michaelmas daisies (as do phlox) seem sensitive in Spring before and as they emerge. I have learnt to be really careful. Later in the season large plants are much more resistant to a poorly directed spray.

Michaelmas daisies grow well on most soils and are fairly tolerant to poor drainage. Last Winter was exceptional and parts of my garden had standing water for a long time. I lost one plant and another sick novae angliae convalesced to only half the height of its identical neighbour.
The village plot has been flooded for several months in two Winters now. No daisies survive bar one. (Fortunately a village wide drainage project will make it worthwhile to plant more)

The Garden Centre’s curse
Displayed in their pots at the garden centre they were very tempting
When I look at my dozen different beloved long standing varieties there are none bought at a Garden Centre. I mean those shops of the glitzy kind where you are obliged to walk through copious frippery to get to the plants.
All mine were obtained from specialist nurseries, plant fairs or mainly gardening friends. I have bought plenty at garden centres but none have survived. They have either died or I have thrown them away.
What goes on when garden centres are supplied by such very fine growers?
Trouble is such grower’s perfect product is a nice display on the sales bench. Who cares if it actually grows in a real garden.

I immediately potted them on into a soil based compost 
I have written before about soft plants forced in polythene tunnels with artificial heat, loads of nutrients and perfect propagation compost. Compost ideal for its purpose of wet speedy liquid fed production is not really suitable for the garden. Once the protective systemic fungi wears off such plants succumb to all manner of diseases - that is if the wind or cold has not shredded them first. In the case of many modern Michaelmas daisies the dwarfed flowering display never looks so good ever again - when the dwarfing agent wears off and the mildew takes over.
You will see from the pictures that I have been tempted yet again.

Four weeks later. There is little hope that they will grow out of the powdery mildew but I will give them a chance next year...
A real Michaelmas daisy
In one of my earliest posts I declared my undying love for Aster amellus 'Violet Queen'
I wrote a long rambling article about hard and soft growth

Read about my labour saving herbaceous border

Saturday 17 November 2018

Our overlooked ancestor

Going the whole hog
Perhaps we are related
Hybridisation is now recognised as a significant factor in recent human ancestry when genetically close hominids mated together. Why do we fail to recognise hybridisation has always been an agent in evolution including our own?

Most of us were comfortable with the idea that we shared an ancestor with a monkey. More recent research suggests we are actually descended from a monkey such as an early chimpanzee or a bonobo. Why does the suggestion that the pig might also be a close relation be treated with scorn and derision?

As regular readers know I have no special expertise in genetics. I have always been fascinated by evolution but write merely as an observer of the insights of others. 
I acknowledge how my articles on hybridisation are strongly influenced by the writing of Georgia University geneticist Gene McCarthy. Today my entire article is based on his thinking.
For decades McCarthy has promoted hybridity as a force in evolution. More and more modern geneticists agree and record hybridisation’s contribution to evolution but even now in some quarters it is not fashionable to say so.

It is tragic that a free thinker such as McCarthy ploughs his own furrow without support and little formal recognition. I cannot find any plausible explanation of why his overall hypothesis of the way of evolution is wrong.
You will have to turn to Gene’s blog to check out the details of most of the things I have to say today.You will be impressed with the fine detail and meticulous research he has applied.
As a good scientist McCarthy agrees that the idea that a pig has enriched our genetic inheritance by hybridisation is not proven. I suspect privately he is pretty certain he is right and I think so too.

Superficial evidence of our porcine ancestry

When you look into a pig’s eyes you might be gazing at a beautiful woman. The only primate which shares this feature of narrow eyes, eyebrows and eyelashes is us. Our skin’s share so many similar features and in our skin’s smoothness and lack of hair we are almost unique.

Although genetic theory states that we and the pig are evolutionarily distant, recent research shows we are very much closer than previously thought and the medical establishment is starting to find all kinds of ways of exploiting a general lack of our cells and tissues rejecting each other. Simple features such as heart valves and lenses can already be grafted between us. No genetic distance at all.

We are the only primate with many of pig’s cartilaginous features such as characteristics of our noses and ears. No monkey has anything like our protruding noses which resemble so much more a pig’s rootling snout

At a less pleasant level I might mention some of our odours are very similar and where we permit it a pig’s level of hygiene is high. Historic records of cannibals say that our flesh tastes and smells just the same. Such cannibals called man ‘long pig’. 
One wonders whether ancient man, so much closer to nature, developed still surviving cultural taboos as a result of our similarities.

The BBC recently waxed lyrical about how human eye contact supplemented our language.They explained our expressive white sclera (the whites of our eyes) are unique to humanity.

It is generally regarded that pigs are the most intelligent animal in the farmyard - except perhaps for the farmer.

A more serious comparison

When a scientist suspects a plant or an animal is a hybrid he makes a long list of common features between the purported parents. McCarthy has done this between pigs and humans; all the features included are NOT shared with any other primate (other than the gorilla that might have a similar hybrid origin to humans).

McCarthy’s list has more than a hundred items, some are one liners, others detailed expositions of such as musculature, skeleton, organs and skin. NONE of these similarities are seriously disputed. Some scientists ponder why we share so much with a pig. They ignore the obvious explanation.

Most of these anatomical and external factors are too technical for my own understanding. For the sake of my argument I attempt to focus on just three

Skin. Including our mutual absence of hair our highly vascularised fatty skin is almost identical in structure and unlike that of any monkey. Our skin’s cooling capacity is outstanding. This is essential for cooling our very large brain. As an animal’s volume increases the problem of heat dispersal magnifies.
The intelligent small monkeys have a relatively small brain/body ratio. Not so the larger monkeys. There seems to be a barrier to large brains because the cooling requirement for a large brain is never achieved. If all our intelligence is to be housed in our small head we need a pig’s skin.

Bipedality. Although at first sight there seems to be no valid comparison there are in fact several pointers to a connection. A pig’s hind legs are longer than it’s forelegs. The pig’s and our own legs and hind skeleton and musculature is structured in such a way that bears little resemblance to that of a monkey. A monkey’s gait, even in those more highly developed with the capacity to walk on two legs show no sign of evolution to the way of our own.
It is conjecture whether the first pig/human hybrid came out two leg walking or developed it later!

Organs. I have no idea of the relative efficiencies of our organs to that of a monkey. Only that some of our organs are more like those of a pig than any monkey. Our kidney's intimate structure and action is the spitting image of that of a pig (perhaps relevant to our mutually omnivorous diet).
It does not follow that all structures in a new hybrid are at first or even ever especially beneficial. When huge numbers of genes recombine in a first hybrid it lives or dies with what it is endowed.
This does not imply that the offspring of new hybrids are not subject to later natural selection of new genes wherever they come from.

Envisaging the first pig/monkey hybrid

Even the most powerful new genetic techniques cannot inform us of what happened perhaps six million years ago at a time before than the appearance of the primate species that text books record as our likely ancestors. 
One can only surmise on our early hybrid origin based on our detailed knowledge of hybridisation and the introgression of genes in well researched modern examples.
Most people have an image of a modern farmyard pig mating with some humanoid creature. They immediately incredulously reject such a notion.

Wild pigs
Think more of two similar furry animals mating in the jungle or prairie (except that the swine might not have been hairy).
In their original habitats such liaisons might have been relatively common just as today mating is not infrequent between geographically overlapping genetically close  genera and species. (Most different species of monkeys can mate with each other if man brings them together)

What would be immensely rare would be such copulation giving rise to viable offspring. Recall however that if something is not impossible on an evolutionary timescale it is likely to happen. There are many parallels of genetically distinct animals that have given rise to viable and fertile hybrids.
Suppose a female monkey gives birth to a female hybrid. The hybrid’s likely fate is that it does not have the constitution to survive. There are however plenty of examples of distant hybrids that do reach maturity and behave as strange but functioning entities. Imprinted mother-love is fiercely powerful in ensuring such offspring’s survival.
If such an organism survived and in this case the monkeys were anything like modern promiscuous bonobos it would certainly mate!

Most hybrids are infertile but no means all. There are myriads of examples of plants and animals with different chromosome numbers crossing to produce fertile offspring.

Where a hybrid mates with one of the parent species it is called a backcross. Perhaps there were two backcross generations before the new form became physically or in some other way isolated to form a breeding community.
(I personally think there is too much pig in us for there to be many more backcrosses)

This kind of supposition does not preclude further liaisons between monkeys and the new species perhaps many generations later. Nor does it preclude introgression of some of the original sow’s genes into the offspring of the monkeys - but of course hugely diluted with thousands of generations of backcrossing and such genes only surviving if they gave strong selective advantage.

All this of course is speculation to how it might have happened. The actual pathway might have been completely different and most of the world denies it happened at all.

Final thoughts
I do not know how this theory will ever be proved. Perhaps more intensive genetic analysis of the similarities between humans and pigs might shed more light on the process. After all many of our shared features demand thousands of genes working in unison. Only if our skins for example achieved their similarities by entirely different gene pathways could the hybrid explanation be rejected.
No-one appears to be looking and you can easily understand why.
Readers might have previously noticed I am sceptical of the cavalier way that geneticists call upon parallel and diverging evolution to explain ‘difficult’ findings. Only yesterday researching this post I read that nature has reinvented the appendix in mammals 32 times! My own feeling is that the introgression of genes shared by hybridisation through chains of similar closely related species is a much more likely explanation of many such findings.

Mr McCarthy’s list of common features shared by pigs and humans and no other primates is extremely impressive and I discern that there is a vague recognition out there that this is an anomaly that seeks an explanation.
I really don’t know if the complex similarities between pigs and ourselves is controlled by arrays of very similar or identical genes. If it were to be so I cannot see any viable explanation exists for our common features other than a long past hybridisation. Classical methods of horizontal gene transfer in my view just don’t hold water as explanations of genetically distant animals (or plants) sharing complex features that are controlled by the same  genetic pathways.

The idea that there was a coastal phase in our early evolution perhaps 5 million years ago is no longer treated with derision. The theory is not entirely incompatible with the pig/monkey theory
A very recent article in the New Scientist positively gurgles over the importance of hybridity in human ancestry over the last 100,000 years. A professorial interviewee states that if you scratched wriggly overlapping lines on a piece of paper that would be our evolutionary pathway! How the story has changed in just a couple of years.
In contrast my article today speculates about a time a multiple of perhaps sixty times longer ago. It is quite ridiculous that with more recent acceptance that hybridisation is part of evolution (and not just an unfortunate artefact that arises from the dabbling of humans) that few seem to consider what hybridisation also occurred much-much longer ago.

Some readers might be interested in an article by Bryan Nelson on the MNN website about the recently discovered close genetic relationship between humans and pigs. He quotes the writer of the paper “ … swine could be placed in a family inhabited principally by primates….”

Reasons why the theory falls on stoney ground

1. Research in this area inspires ridicule and lacks funding. Just read this scurrilous and vindictive article in the Guardian - of all places
2. Successful experiments might in itself inspire ridicule, controversy and rejection
3. Failure to make research progress would destroy a career and label any researcher an idiot
4. Conventional opinion is only moving slowly to taking hybridisation seriously and many scientists’ life work is wedded to the belief that evolution only takes place in straight lines
5. Evolution is already rejected in the world’s hinterland. Don’t rock the boat by apparently changing your mind. Don’t give ammunition to ignorance
6. Should the theory ever be proven it would be a political hot potato

Further pigmentation

Nothing in evolution would surprise me”  - Peter Williams

“They are our closest relatives”  - Michael Wood who has spent a lifetime working with pigs and temporarily overlooked monkeys

“This would be an unlikely coincidence”  -  Scientist commenting on the discovery that the Alu transposable RNA elements in pig and human are the same

“What we saw when living in the African jungle is not recorded in the text books”  - Cathi and Harry Poole

“Despite the great diversity of life, there is a string connecting us all together”  - Bryan Nelson

“My hatched duckling thought he was a hen and bonded with them - even ushered them into their pen at night”  - Cathi

Bryan Nelson's perceptive MNN article

Scroll down on this page of Gene McCarthy's blog to find his list

My own most relevant hybridisation posts
1. About human evolution
2. Resistance to  hybridisation as an agent of evolution

What do you think?

Wednesday 7 November 2018

Growing a pure stand of Chewing’s Fescue(2)

You can do interesting things with this exquisite grass
I prefer to walk on infrequently mown grass rather than bare soil
Sometimes I write for a minority interest. In this case the minority might merely be me. I do get peculiar gardening whims and get this urge to tell you about them. For the last four years I have been  besotted with this lovely fine grass.

There is nothing new about this originally New Zealand grass. Its been around for a very long time - ever since it was discovered by a seedsman in farmer Chewing's field. It is now the major grass constituent in all UK fine grass seed mixtures. What I do almost uniquely is to grow it as a pure stand on its own or as a backcloth to such as wild flowers and bulbs.

The special features of Chewing is that apart from it’s adorable dark green colour, its dwarf habit and delicate fine nature, its general hardiness, suitability to a wide range of environments and soils, is that it has a tufted nature and does not produce stolons and creep.

Cathi's grass verge is colourful throughout the year
This compact nature gives new opportunities albeit used alone it is not suitable for a conventional pitch or lawn where turf is bound together with skilfully composed mixtures optimised for a myriad of sports and ornamental situations. A  Chewing lawn  lawn might have a tufty uneven nature and you all know the phrase “don’t have all your eggs in the same basket”.

The original Chewing species has been extensively ‘improved’ by the huge worldwide turf seed industry. Like all turf grasses the trade recognises many distinct cultivars each with special strengths such as colour, hardiness, Winter wearing and dozens of other useful attributes. 
Very confusing. My own experience is with the cultivar ‘Wagner’ - although if you buy as a layman as I do you will be lucky to have Hobson’s choice.

The problem of weed grasses
This is a later extension of Cathi's verge -  a work in progress
Most soils are full of weed grass seed and in some cases suitable wild species.
Although lawns are not my real subject today, very few of them are composed of the grasses that were actually sown. With highly skilled and intense management they nearly might be but let’s face it most of our lawns bear no resemblance to the original mixture and this includes most of my own. Garden genius Peter Williams has an acceptable sward at the bottom of his garden that he never sowed at all. He just started mowing and let the wild grasses come in.

A groundsman once told me that if ever a selective grass weedkiller was invented to kill annual meadow grass if he used it he would not have a lawn left. 
Indeed this encapsulates the problem. Where lawn weeds are dicotyledons (broad leaved plants) there are selective weedkillers to kill them; not so for weed grasses.

How to achieve a pure sward
With great difficulty and most people fail.

Never mown this fescue path has been trimmed with my battery electric strimmer once only to prevent flowering
The basic technique exploits the principle of the ‘stale seed bed’. This is where sowing conditions are established and then left alone for surface weed seeds to germinate.These are then repeatedly sprayed off (or shallowly hoed). Best for a whole season or even longer. Old time farmers used it to clobber particularly difficult ‘seasonal weeds’.
In my own case I can go better than this where for years I have kept land free of seeding weeds by regular glyphosate spray and as a none digger have not brought buried long dormant seeds to the surface.
1. The village plot is an example where a regularly sprayed bark path after many years had faded away. I just scattered Chewing fescue and with hardly any hand weeding quickly had a uniform stand. (‘Quickly’ for me might be more than a year!)

2. I am starting to use Chewing fescue as a ground cover in the wilder parts of my glyphosate managed garden and it was equally easy to establish.

3. In Cathi’s grass verge where I eliminated perennial weed from original coarse grass completely overgrown with ground elder the process has been more complicated. You can read about this conversion if you use my search box. The project involved keeping the best of any surviving ‘wild grass’ and scattering fescue seed

4. Lyndi’s overgrown ancient horse paddock had no grass left when I sprayed off the rampant nettles and otherwise mainly annual weed. You can read about this too and as explained later it is not as easy to get the right grass growing.

5. Sixty years ago in my then small garden I sowed a conventional fine grass lawn. I was able to get a free supply of ‘spent’ John Innes compost from Askham Bryan college. A one inch mulch over the soil surface was sufficient to suppress germinating weed grass seed. It worked very well.

The process of establishment
As long as you can identify Chewing you need not identify any other grass. You just pull or cut out out none fescue grass or very carefully spray it. No hesitation, as soon as you see it it has got to go. If the foreign grass removal leaves a large empty space no matter, you can sow (or plant) some more fescue later 

Spraying out grass weed of course is harder and is only necessary on large scale sowing - and you need to have experience of low pressure directed squirting with a knapsack sprayer using almost zero pressure. To achieve success with spraying you need to sow very thinly indeed  - very much less than if you were sowing a lawn. It is impossible to select out weed grasses when amongst dense cover of fescue seedlings. I am prepared to resow if necessary umpteen times. After all even in a quarter acre field it only takes a few minutes. It might of course take a long time to achieve your heart’s desire.

Not yet sufficient cover but I hope you can see where I am going
In Lyndi’s large field it has been a process of attrition. This project has been much more than establishing stands of fine grass. She has already had two years of outstanding displays of thousands of bulbs and (as yet not very exciting) summer colour of annual and perennial ornamentals My aim is only about 35% Chewing’s grass cover and I am half way there.

A work still in progress
The village plot path was so much easier and quicker. There were very few grass seedling weeds and I was able to sow relatively densely, rely solely on hand weeding and only resow once. Within a year it was a very adequate grass path which never needs mowing.

The very good news about establishing fine fescue grass from seed is that the inevitable broad leaved weeds can be taken out by overall spraying of selective lawn weedkiller. Even better, unlike most other lawn grass seed fescues are unharmed even when very small.

A note about hand weeding
I know a few readers do not like to use herbicides and hand weeding a lawn sounds too stupid for words. Not so. Provided you started with some kind of stale seedbed management before sowing, are prepared to sow thinly on more than one occasion and are not in a great hurry, hand weeding works extremely well. In another project I have been doing this in a hundred square metre project. I find it easy, effective and curiously addictive. Just ten minutes twice a week over several months! When eventually densely established, fescue does not give other grasses a look in.

What you get with a Chewing sward
Not usually a lawn although with appropriate mowing with blade set high rather a nice meadow which perhaps needs one third the cutting of a standard lawn.

Perhaps I should strim a little more 

As an extreme Cathi’s verge and the village grass path get no mowing at all. In their second year this season I did go over once with my Black and Decker battery operated strimmer. Without such cutting in June the grass will flower. Any later golden seedheads are not unattractive and in Lyndi’s field I am anxiously waiting the results of a little self sowing. (When at last we actually get some real rain!)

Flowering and seeding fescue might not be your cup of tea but is not unattractive
In grassed down spaces  and meandering paths in my own giant mixed borders I wander in with my bog standard rotary mower at perhaps every fifth cut of my lawn. I set my mower blade close to near how high it will go.

Just twice mown this Summer with the blade set high
I have been surprised and delighted to find how easy this has been. I expected weed grasses to need a lot of special extermination. They certainly do in the establishment period and I am totally obsessive in Lyndi’s field for example to slay none fescues on my routine spray round - clumps of fescues are just another plant to avoid. This latter example where I need to spray anyway (as I do in my cemetery gardens) is as little extra effort as if the fescue was not there.

What has really impressed me is how the density of the fescue sward in my more advanced projects has almost completely suppressed and prevented wild grass infiltration. Large grass swathes on the village plot now needs no glyphosate spraying at all when the whole garden gets my routine monthly spray. My spraying time has been reduced by a quarter.

You might ask what happens where I grow wild flowers and herbaceous garden plants in the grass. This really needs a future post to explain. The beauty of Chewing is that it does not spread laterally by stolons. Spray a stoloniferous grass with glyphosate and it dies back a very long way!
If in my mixed plantings a highly desirable plant is threatened by grass competition the grass gets a well directed glyphosate squirt. In point of fact most successful plants outgrow the grass at their station. Bulbs are ideal, they just pierce through the grass and when they die down the grass restores its supremacy.
I do not want to encourage anyone to attempt to convert their existing lawn. By all means oversow with fine grasses and encourage them with such as iron sulphate and frequent scarifying.  You will never selectively eliminate entrenched undesirable grasses. Established stolons and rhizomes run a long way and if you selectively spray even with great sensitivity you will still get huge yellow patches. Even were you successful an old lawn’s soil contains an abundance of seed of wild grasses

I have written about this fescue before and it inspired very little interest
You can buy Chewing's fescue here from Emorsgate Seeds
There are several posts about Cathi's grass verge and the post about Lyndi's field is my all time second most popular

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