Driving around Pennsylvania or Northamptonshire, while keeping my eyes on the road, my peripheral vision always takes in what’s growing by the roadside. And there’s plenty to see.
One of the very first posts on this blog, way back in 2007, was about unexpected roadside plants and here we are almost ten years later and over the last few days I’ve spotted some more.
First, let’s revisit the Heathrow euphorbias (above). Having driven round the exit from London’s orbital motorway, the M25, for Heathrow every few months for more than fifteen years – about four years ago I spotted Mediterranean euphorbias bursting through the barrier. Driving my wife judy to the airport last week she snapped this picture on her phone through the car window as we whizzed by. Those euphorbias are still going strong.
Later, on the way home to Northamptonshire, I spotted something interesting as I turned off the northbound M1 motorway to head home. And it turned out to be a strange mixture of plants: stinking hellebore (Helleborus foetidus) (below) scattered by the side of the road along with Euphorbia amygdaloides var. robbiae, grape hyacinths (Muscari), jonquil daffodils, flowering currant (Ribes sanguineum) and more: a strange mix of garden plants at an exit that’s a long way from a garden.
And then just yesterday, on the way back from the recycling centre, doing very nicely by the roadside – two or three patches of another Mediterranean plant: Alexanders (Smyrnium olustratum) (above right). The Flora of Northamptonshire tells me that it: “originates from it formerly being grown as a medicinal herb”.
Now that our roadsides are not treated like lawns and mown every two or three weeks, there’s more and more interesting plants to see.
I’ve been doing some weeding. This is in our British garden where the weeds are always jumping at this time of year, especially when it’s been so wet and it’s been unwise to get on the soil.
I’ve also been having a clear out, bringing files and folders out from the back of the file cabinets and what did I find? My weed collection, three fat folders of pressed plants, that I made when I was a student at the Royal Botanic Gardens at Kew in London almost forty years ago (below right, click to enlarge).
And the first pressed plant I found in the first folder I opened was the same plant I’d just been pulling out of the garden: hairy bitter cress (Cardamine hirsuta). We have a close relative, Pennsylvania bitter cress (Cardamine pennsylvanica) in our American garden.
And this brings me to my first rule of weeding: our top weeding priority should always be to pull out are the weeds that are in flower or developing seeds. Hairy bitter cress rarely grows more then 10in/25cm high but can still can produce 700 seeds and fling them 31in/80cm, but it can also produce seeds when just two inches (5cm) high. So pull it out. Now.
Many of the traditional rules of gardening have little value but “One year’s seeding makes ten years weeding” really is true. Dandelions (below), which as annoying in Pennsylvania as they are in Northamptonshire, can produce over two hundred seeds in one seed head. So - obviously - don’t let them seed.
My second rule of weeding is always to shake the soil off the roots after you pull out the weeds and before they go on the compost heap or (in those cities with green waste recycling) in the green waste bin. You can ship out a huge amount of good soil if you’re not careful.
And my third rule of weeding is this: get them when they’re young. When nasty perennial weeds like bindweed come through at this time of year, a one inch shoot is often an indicator of yards of root underneath. Later, when their twirling stems become entwined with our garden plants, it’s all but impossible to remove them. It’s so much easier when they’re just an inch high and, at this time of year, if you disturb the plants you’re trying to protect when extracting bindweed roots they’ll soon settle down again. By the time the bindweed is strangling your cistus (top) it’s far far FAR too late.
My final rule is this: Don't spend half a day weeding and then the rest of the week nursing your aching back. I did half an hour this morning and half an hour this afternoon and I’ll try to keep that up. But if I’d spent two hours forking out weeds at a single stretch this morning (as I was tempted to do) I’d not be able to get out there again tomorrow or the next day or the rest of the week. Little and often…
OK, it's time to get back to the bindweed and dandelions and the dreaded hairy bitter cress.
I’ve been trying to get out for a good walk every day - weather permitting - since I’ve been here in Britain and since a few chilly nights brought the last of the fall foliage to the ground the hedgerows are revealed as dripping with fruits.
Two plants stand out, their vivid red fruits shining brightly in the low late autumn sun.
There are two unrelated forms of bryony and the one with the crowded clusters of scarlet fruits now at their peak in the British hedgerow is known, perversely, as Black Bryony, Tamus communis (left, click to enlarge). Closely related to the yams of the tropics, this is a vigorous twining plant, snaking its way through woody hedge plants. As well as its scarlet berries it has fat tuberous roots, deeply ribbed triangular leaves, small green and white flowers – with male and female plants on different plants… And every part of the plant is poisonous.
It’s sometimes used as poultice to treat internal injuries but, frankly, it’s best just to admire it from a distance. Gardeners around the world can order Black Bryony seeds from Plant World Seeds.
The other plant that stands out is the dog rose, Rosa canina (below, click to enlarge), a much more substantial, even imposing, feature of the hedgerow with clusters of red hips which are a little less shiny than the black bryony berries so that they gleam in the sun but look more dull in the shade.
Mind you… I say dog rose, Rosa canina… But these hedgerow roses come in a confusing number of micro species, about thirty very similar but slightly different species some of which have five or even six times as many pairs of chromosomes as usual. They also have a slightly quirky form of reproduction known as permanent odd polyploidy – but you and I can both be delighted that I’m not going to try and explain it.
But what I can do is remind you that rose hips can contain as much fifty (yes, FIFTY) times as much Vitamin C as oranges! So those hedgerow rose hips can bring you a genuine health benefit. There’s more about Vitamin C in the hedgerows in a post from September last year. Gardeners around the world can also order seeds of Rosa canina from Plant World Seeds.
The final fruity feature of the Northamptonshire hedgerows along which I’ve been walking these last few days has been the sloes, Prunus spinosa. These are like small plums in both their appearance and their botanical connections – but not in taste. “Tart” is hardly the word but sloes make a fantastic flavored gin, as I discussed here back in 2007.
One other thing I’ve noticed these last few days is that the birds haven't got stuck in to all these fruits yet. But this looks like an exceptionally good year for hips and berries and other fruits, all of which will help so many birds, and small mammals, through the winter ahead – however tough it turns out to be.
There’s been a great deal of controversy about whether native plants are best for pollinating insects or whether non-native garden plants are just as valuable. On the whole, the debate has been informed by more opinion than science but, after a four year research project at their Wisley garden near London, the Royal Horticultural Society has the answer. This is the first ever designed field experiment to test whether the geographical origin (‘nativeness’) of garden plants affects the abundance and diversity of invertebrates (wildlife) they support.
“Until now the role native and non-native plants play in sustaining wildlife in gardens has been unclear and confusing,” say the lead researchers on the project Dr Andrew Salisbury and Helen Bostock. “Now, for the first time, gardeners can access robust, evidence-based information on the most effective planting strategy they can adopt if they wish to attract and support pollinators.”
Over on her Plants For Bugs blog, Helen Bostock summarizes the three main conclusions of the research (her emphasis in bold).
“1. The best strategy for gardeners wanting to support pollinating insects in gardens is to plant a mix of flowering plants from different countries and regions.
“2. Emphasis should be given to plants native to the UK and the northern hemisphere, though exotic plants from the southern hemisphere can be used to extend the season (there are a greater proportion of exotic plants flowering later in the season compared to UK native and northern hemisphere plants) and provide nectar and pollen for some specific pollinators. (Left, Verbena bonariensis from South America)
“3. Regardless of plant origin (native or non-native), the more flowers a garden can offer throughout the year, the greater the number of bees, hoverflies and other pollinating insects it will attract and support.”
So there you have it, research at the RHS (part of the research area above, click to enlarge) the best way to encourage pollinating insects is to “plant a mix of flowering plants from different countries and regions” – and not to rely only on native species.
Supported by the Wildlife Gardening Forum, this is exactly the sort of research we need to demonstrate the proven realities of an issue which has been dominated by the trading of opinions such as “Native plants will attract more native pollinators” masquerading as facts.
Let’s hope the RHS team will soon be looking at the relative importance of native and non-native plants in providing food for those larvae of native insects which do not require specific native plant species on which to feed – for although the point is pretty much proved in Jennifer Owen’s Wildlife of a Garden, it would be good to have research on the same scale this newly published RHS research to make the point.
* You can read the full details of the RHS research online in the Journal of Applied Ecology.
* Take a look at the latest addition to the RHS guidance on Plants For Pollinators based on this research.
* Read the background to the research and how it was done.
As I mentioned here recently, there’s a plan to change the classic botanical name of the Welsh poppy, Meconopsis cambrica. Chris Grey-Wilson, the world’s leading expert on Meconopsis, first proposed the idea of restricting the name Meconopsis to the Himalayan poppies in the botanical journal Taxon in 2012. He repeats the suggestion in his stunning new monograph on Meconopsis, which was published recently, and proposes a new botanical name for the Welsh poppy.
Actually, what he says, basically, is this: if you apply all the legitimate and agreed botanical rules, the Welsh poppy is in fact the only true Meconopsis. All the Himalayan blue poppies that have captured our imagination for so long are, botanically, so very different that they need a genus of their own. Fair enough.
But, because all the blue poppies are so fabulous and so well known to gardeners, we should call them Meconopsis and call the Welsh poppy something else. Technically, the Welsh poppy should probably be put back into the genus Papaver, where our old friend Carl Linnaeus first assigned it back in 1753. But, for various botanical reasons I needn’t go into, that would mess up the taxonomy of the seventy or so other species of Papaver. So Christopher suggests creating a new generic name: Parameconopsis. The Welsh poppy would become Parameconopsis cambrica.
He says that continuing to call the Welsh poppy Meconopsis cambrica and creating a new name for all the others “would be widely deplored in the botanical and horticultural worlds”. I wonder…
I’m entirely happy to accept that the two need to be separated. But, frankly, it sounds to me as if he simply wants to give the everyday, easy-to-grow, self-sows-everywhere plant a new name and retain the well known name for the tricky-to-grow ones with all the exotic and romantic Himalayan associations.
So I thought it would be interesting to see what the Welsh thought about all this and I asked Simon Goodenough, Curator of Horticulture at The National Botanic Garden of Wales.
“The Meconopsis debate has begun here in Wales,” he told me, “and there are a number of people who disagree with the idea of changing the botanical name of the Welsh poppy. However, I think changing its name will be a great opportunity to raise its status as a unique plant and one which Welsh botanists, gardeners and the people of Wales can be proud of. The National Botanic Garden of Wales will celebrate this change, however it plays out.” So, “always look on the bright side” is the message. Rather clever, actually…
As I said, it’s not the first time the Welsh poppy has had a change of name. Our old friend Carl Linnaeus named it Papaver cambricum back in 1753, but then in 1814 a botanist called Louis Viguier separated it out into a genus of its own. You see why here. It’s also been classified as an Argemone, a Cerastites and a Stylophorum – but let’s not dig all that up. Now, it’s going to be Parameconopsis cambrica. But I have the feeling that when someone finally takes a good long look at the whole poppy family it might be on the move again.
Oh, and in case you’re wondering… Gardeners in Britain and in North America can order seven different forms of the Welsh poppy, whatever its botanical name, from Plant World Seeds - including this double orange.
It’s purple loosestrife season here in Pennsylvania. Swamps and other wet habitats are vivid in its purple coloring (above, click to enlarge), in some places it looks as if it’s smothered everything. This colourful European native is generally viewed as a destructive menace and many millions of dollars are spent every year in a futile attempt to eradicate it.
In Britain, by the way, where purple loosestrife (Lythrum salicaria) originated, it’s far less common and is a popular plant for bog gardens with over a dozen named varieties, two of which have been awarded the prestigious Award of Garden Merit by the Royal Horticultural Society.
In North America, purple loosestrife is generally regarded as evil but part of its reputation derives from the simple fact that it’s so colorful, it’s so obvious that it’s there. If it had dull brown flowers no one would notice. Ken Thompson, in his important book that I reviewed here recently, put it this way: “Very tall people with red hair, big tattoos and conspicuous facial scars rarely have successful careers as bank robbers, and purple loosestrife has a similar problem: it’s just too conspicuous for its own good.” He goes on to emphasize: “Recognition of loosestrife as a problem was largely based on anecdotal observations, which are likely to be particularly unreliable in the case of a tall species with such bright, obvious flowers. This is a well known problem that standard textbooks warn against: it’s easy to conclude that an otherwise rather dull wetland has been completely taken over if you look at it when loosestrife is in flower…, even if a more careful examination would reveal no such thing.”
My local experience indicates that it does not necessarily spread once the first plant arrives, and that it can also decrease over time. On the lake where we live, I spotted two plants growing together about ten years ago. I checked the whole lake last week and those two plants are still the only ones present in spite of there being many suitable habitats all along the margins. Native swamp loosestrife, Decodon verticillatus, is far far more aggressive.
And in the swamp where I first saw it flowering colorfully it has declined, as it has elsewhere, and a striking feature is that native shrubs including dogwood (Cornus) and arrowwood (Viburnum) are establishing themselves on individual clumps of purple loosestrife.
And it’s not as if purple loosestrife is entirely useless for wildlife. It’s been shown that a number of native species are more likely to grow in habitats containing purple loosestrife and in a study of over 250 plots it was found that there were more birds in those with purple loosestrife than in those without. I’ve seen around thirty individual butterflies on one plant and over sixty insect genera use it, including adult monarchs (left, click to enlarge). Birds even nest in it. Another significant study that looked carefully at this issue found that there was no difference in species richness between plots with and those without purple loosestrife.
Ken Thompson says, as he concludes his discussion of the issue: “Persecuting loosestrife is, and always has been, a waste of time.”
I was tempted to pull out those first two plants that appeared at the far end of our lake but I just left them and kept an eye on the situation. Ten years later they’re doing no harm.
Don’t get me wrong. I’m not saying that anything and everything that could be, and is, invasive should just be left alone. What I am saying is that it’s not as simple as “native good, non-native bad”. Especially when you look at how fast US native swamp loosestrife (Decodon verticillatus) can spread and the monocultures that result.
Monarch butterfly on Purple Loosestrife (Lythrim salicaria). Image © Liz West (http://www.EWestPhotos.com). Used here under Creative Commons Attribution 2.0 Generic License.
In Britain, this invaluable book is subtitled The Story and Science of Invasive Species; in North America, the more provocative subtitle is Why Invasive Species Aren't All Bad. Both are appropriate; look dispassionately at the science and it’s clear that invasive species are not all bad.
So often, discussions of the whole issue of natives and non-natives (plants, animals, insects and the rest) are run through with the repetition of bold assertions, unproven by science, that it’s a relief to find a book in which the whole issue is viewed more calmly, in a broad context, considered over time, and backed by solid science. It's just what we need: more unbiased science and less thoughtless hysteria – and that is what this book provides. And it’s all presented in a lively, and very readable.
Ken Thompson discusses how we define “native” and how we stretch our objective definitions to take account of subjective impulses; he reveals how little we actually know about so many non-native species and how very few ever cause problems; he examines whether the most hated invasive species really are as destructive as we’re told and points out that some have positive impacts; he discusses how natives and non-natives can happily co-exist in the same habitat; he applies science to the myths surrounding invasive species.
One of the striking features of the response to the presence of non-native plants, in North America in particular, is the frequency with which they’re simply removed – just in case – rather than studied. As Dr Thompson points out, the proportion of non-natives that arrive in natural habitats and end up causing problems is minute. And when non-natives are studied over the long term, we sometimes find that their initial dominance is followed by a sharp decline followed by a stable balance.
I won't steal the author’s thunder by summarizing his invaluable discussion of how we define the word “native”, except to say that picking any date as a cut-off point after which an arriving species is declared an alien is clearly arbitrary and ignores the fact that ecosystems have always evolved over time and continue to do so. And suggesting that only new arrivals in natural habitats that are unassisted by man can be classified as “native” ignores the obvious fact that nowhere on the planet is unaffected by man’s influence, so nowhere is genuinely “natural” anyway.
So. What a refreshing book and one that’s full of stimulation and reminders to look at the evidence and not listen to the hearsay. This book effectively skewers the prejudices and pseudoscience of the plant police extremists for whom natives are, by definition, good and non-natives inherently bad. It should be read by anyone with an interest in native and non-native plants, by those working in the field, and also by natural history and garden writers like me - so we don't simply repeat misconceptions in our work. The book is stimulating and refreshing: as soon as I got to the end I immediately started again at the beginning. [The anwser to the book's title, by the way, is a fascinating one. Needless to say, it's not what you think.]
Where Do Camels Belong?: The story and science of invasive species by Ken Thompson is published in Britain by Profile Books. It will be published in North America as Where Do Camels Belong?: Why Invasive Species Aren't All Bad by Greystone Books in September. North American readers who are eager to read it before September can order the British edition from amazon.com.
Out walking in the woods again yesterday, and I found ten clumps of hellebores! They look to me like a form of green hellebore, Helleborus occidentalis, with unusually large flowers; there was one very prolific clump (above, click to enlarge) and the rest were smaller, with some clumps too small to be flowering. All were scattered across an open east facing bank. Now hellebores are not native to North America – so what were they doing there? A couple of miles from the nearest house.
Actually, it was pretty obvious. The bank was at the edge of an unusually flat area; other non-natives were around including dense thickets of forsythia (below, click to enlarge - usually a sign of an old homestead), broad patches of Japanese pachysandra (Pachysandra terminalis) and bugle (Ajuga reptans), and three individual grape hyacinth (Muscari botryoides) bulbs with a single spike of flowers on each.
I’d say it was the site of an old homestead and this was confirmed by the fact that the whole area was relatively open compared with the surrounding forest. There was also what seemed to be the remains of a stone built water cistern, sunk in the ground and partially overgrown. And the trail along which I’d been walking when I spotted the hellebore clumps in the distance turned out to be a paved road that had been closed and become overgrown.
So, even though there was no sign of tumbledown walls, at some point in the past there must have been a house there and either the timber construction had simply rotted away or it been removed to be used again elsewhere. Helleborus occidentalis has a number of medicinal uses so it’s not surprising to see it on such a site.
Still – flourishing hellebores growing in the Pennsylvania woods 3000 miles from their native home in western Europe (including Britain) was quite a sight to see. Of course there are some people who’d have them ripped out as “invasive aliens” – see my recent piece on snowdrops. So I’m not going to say exactly where they are!
At least when you see this plant by the side of the road, the answer to the question: “What’s that doing there?” is clear. This is soapwort, Saponaria officinalis, growing by the roadside here in Pennsylvania and since earliest times it’s been used to make soap.
Found wild in Southern Europe, and growing over much of Britain but perhaps native only in the south west (the botanists seem undecided), this pale form is the one seen in here in PA though in some areas a darker rose pink form is seen, and a pale semi-double form (‘Rosea Plena’) also sometimes establishes itself in the wild.
It was brought to North America by colonists specifically for its use as soap and for use in brewing, and long ago escaped from homesteads. It can be made into a very gentle soap - it’s said to have been used to clean the Bayeux Tapestry - and there’s little in the North American native flora that will do the job, especially in colder areas. Soapwort is hardy down to zone 3 (-40C/-40F). Boil it in rainwater to create a mild soapy lather. It’s been used to help create a head on beer, and is also used to make halva.
To be honest, the plant is a bit of a thug, even in poor soil it grows vigorously as long as it has plenty of sun, and it takes the salty run-off from roads in its stride. In fact it’s so adaptable that it’s naturalized in every American state except Alaska and Hawaii. Here in Pennsylvania, it often grows along roadsides with double-flowered daylilies – about which more next time.
A neighbor came round to take a look at the garden yesterday, and one of the things she was most impressed by was – bugleweed (or simply bugle, as Brits say).
We have quite a few different forms, none of them in flower of course, not in July, and while she admired the prettily coloured variegated sorts like ‘Burgundy Glow’, she was especially struck by the efficient ground covering prowess of the plant in the picture (above, click to enlarge). And it’s certainly impressive.
From a single root dug up from under the satellite dish at the radio station where I do my music show every week, in five years it’s spread to this dense covering about 5ft x 6ft. The only plants to penetrate are self sown helleborine orchids.
But this is not just any old bugle. The reason I dug up a little piece in the first place was because it looked so dramatic with tall white spikes of flowers, instead of the usual blue. In the shade under our maples and oaks, the tall spikes look wonderful in full flower. And they’re good cut for spring posies, too.
It looks as if the name for this plant is Ajuga reptans f. albiflora ‘Alba’ (right, click to enlarge) but I remember seeing a white-flowered bugle at the Chelsea Flower Show a few years ago under the name of ’John Pierpoint’ which seemed to be more compact, with much shorter flower spikes. White frorms turn up in the wild in its native Britain, occasionally, but I've only seen ever seen one spike - on a farm track near where Cream drummer Ginger Baker used to live years ago...
So, anyway, our neighbor will be receiving a batch of little parcels, small pieces of the various bugles we have around to get her started. And she’s already received a warning about how rapidly they can spread. You should see our “lawn” in the spring… More blue bugle flowers, than green grass.