This is a tale of two corydalis. One spreads steadily, but very slowly, the other is worrying the invasive plants people.
Corydalis solida ‘Blushing Girl’ (above) is a spring ephemeral for woodland conditions, at its peak today. It comes and goes relatively quickly in spring, then its little tubers sit and wait to do it all again the following year. The soft pink of its crowded flower heads is lovely, but it spreads only slowly.
Corydalis solida has a wide European distribution and this form originates from the great Latvian plantsman Janis Ruskans. It was available in the US from the late lamented Seneca Hill Nursery but no one, not even Odyssey Bulbs who list a huge range, seems to list it. In the UK, there are three stockists.
Since I’ve started feeding my clump with Miracle-Gro it’s spreading; I split it last year and it’s increasing noticeably. However, no seedlings. This is because individual clones of Corydalis solida are self incompatible – they will not set seed when fertilized with their own pollen. I’ve been tempted to buy one or two different ones, so they’ll cross and I’ll get seedlings. Now I wish I had, but I'd been trying to be sure that the lovely ‘Blushing Girl’ stayed true.
By contrast, there’s Corydalis incisa. This is an annual or biennial from Japan, Korea, Taiwan and China described as “startling” by the authors of the excellent book Bleeding, Hearts, Corydalis and Their Relatives (Available in Britain from amazon.co.uk and available in North America from amazon.com). They also say that they’ve seen it naturalized along the Bronx River in New York City.
As you’ll have guessed, no incompatability problems here and it now seems to be spreading in the City sufficiently to have alerted The New York Botanical Garden. It’s also been spotted elsewhere on the east coast: Maryland, DC, and Virginia.
This is not a plant that’s widely grown in gardens, it’s stocked by four UK nurseries and by Sunshine Farm & Gardens in the US so, I have to say, it’s entirely possible that it escaped from one of the City’s botanical gardens!
But let’s not get carried away. Of course, we don't want another plant smothering our natives along river banks and in flood plains. But it It’s only been seen as an escape for a few years – which, in ecological time, is just a moment– and, as we know, sometimes plants that seem threatening just fade away. In the meantime, enjoy ‘Blushing Girl’ and the many other forms of Corydalis solida. I’m going to keep pouring on the Miracle-Gro and take a closer look at those listed by Odyssey Bulbs.
The blue poppies are amongst the most tantalizing plants we grow – or try to grow, at least. These exotic relatives of the corn poppy and Oriental poppy instantly attract visitors in any gardens where they’re in bloom. The Himalayan blue poppy… the very name is exciting. We’re almost in Indiana Jones country…
But there’s no doubt that not only are many species difficult to grow but their classification and naming has all been more than a little baffling. So the arrival of this fat – nay, enormous – new book from the Royal Botanic Gardens, Kew, and the expert on Meconopsis, Christopher (Kit) Grey-Wilson, is very welcome.
So, first of all: 300 pages, 300 color pictures, large format (almost 12in x 10in/30cm x 25cmm), spectacularly thorough (except see below) and amazingly detailed. The photographs are superb, many of plants are seen in their wild Himalayan home which is not only a treat in itself, but also helps inform us on how to grow them. The writing is admirably lucid (as we would expect from Mr. G-W), especially considering some of the difficult botanical issues that he discusses. It’s such a relief to have all the classification and naming set out in a way we can all grasp.
But, to be clear: This is primarily a work of botany, and not a work of horticulture. Based on the latest field, herbarium and laboratory studies Kit has completely revised the classification of the whole genus, given us detailed new descriptions of all the wild forms and published many new names for the first time. Garden hybrids and garden cultivars are not usuallly discussed and even some that have received the RHS Award of Garden Merit in recent years are not mentioned. As I say, this is not a book for gardeners.
There are many striking results of all this, but two stand out. Firstly, the name Meconopsis baileyi is now, again, the correct name for what we all finally got used to calling M. betonicifolia – the blue poppy most often seen and the easiest to grow. Secondly, our old friend the lovely yellow Welsh poppy, so familiar as Meconopsis cambrica, and native not only to Wales but Ireland and parts of south west England, and naturalized all over Britain, is now Parameconopsis cambrica. (More on that another time…)
So. This a very impressive work, and the culmination of many decades of dedicated and insightful study in the field, in the herbarium and in the laboratory. It’s an amazing achievement. But, as with The Genus Erythronium that I discussed here in December, it’s expensive: $112/£68. Isn't it time these books were published as ebooks for a third (a quarter?) of the price?
Kit taught me taxonomy when I studied at Kew many decades ago and he was mad about meconopsis then. This book is the triumphant culmination of a lifetime of study. Perhaps, next, he’ll give us a book for gardeners.
The Genus Meconopsis by Christopher Grey-Wilson is published by Kew Publishing in Britain and by The University of Chicago Press in North America.
Botanical science is the basis for all serious discussion of garden plants, the foundation for everything we know about the plants we grow. By classifying and describing our garden plants in an impartial scientific way, science provides a dependable basis for discussing and growing the plants. And the public expression of this fundamental research is the botanical monograph.
For more than twenty five years the Royal Botanic Gardens, Kew, the greatest botanical institution in the world, has been publishing a series of monographs in association with the venerable Curtis’s Botanical magazine, founded in 1787. The latest title has recently appeared.
The Genus Erythronium (cover left, click to enlarge) continues in the style of its predecessors. The simple and elegant design of the pages entices us into the depth of the comprehensive content while the fourteen paintings, shared mainly between two fine, artists Christabel King and Pandora Sellars, combine the beauty of the individual species with botanical accuracy. These are augmented by more than sixty photographs, and 30 color distribution maps (below, click to enlarge).
The text by Chris Clennet, the Gardens Manager at Kew’s satellite garden at Wakehurst Place in Sussex, covers the 29 species with the thoroughness we expect although it’s only fair to be clear that the language of the descriptions is necessarily botanical. The natural distribution and ecology is discussed thoroughly and there are very helpful notes on the cultivation of each species are the result of years of experience and research.
There’s also an invaluable descriptive list of 49 garden hybrids and selections, the plants that are most widely available from nurseries and which most non-specialist gardeners actually grow. Included are useful notes on the distinctive features that separate similar plants.
The book is not intended for the occasional gardener. But for serious enthusiasts and growers, and for people like me helping everyday gardeners choose good plants and grow them well, books like this are indispensible.
I was fortunate to be involved in the publication of the very first books in this series, back in the late 1980s, and it’s heartening to see that the tradition is thriving. However, my admiration and appreciation of these books is tempered a little by one important point: the price. In spite of support from the Finnis Scott Foundation established on behalf of my old friend, the legendary plantswoman Valerie Finnis, this 148 page book is listed at £52.00/$85.00, which puts it beyond the range of many who would appreciate it. But it’s made me want to plant more erythroniums.
Look out for the latest in the series - Meconopsis. Out in the UK now, due in the US in January.
The Genus Erythronium by Chris Clennet is published by Kew Books and distributed in North America by the University of Chicago Press.
For more on erythroniums, see my blog post from back in 2006.
A new series of books for gardeners on individual plants is a big deal. In recent years we've seen fewer specialist plant books published and, as the market for books on many plants is limited, publishers will rarely sanction a new book on a subject even if an earlier one is not up to scratch.
Neither will publishers produce different editions for the British and American markets. So the one book on a specific plant has to provide good information for both British and American gardeners – and this is a definite challenge when the gardening conditions and techniques are so different, tastes are so different, and the plants grown are often very different.
The first four titles in the new Plant Lover’s Guides series from Timber Press came out earlier this year. I’ve been using them, let’s see how they stand up. There are four titles: Dahlias and Snowdrops are written by Brits, Salvias and Sedums by Americans. All the books share the same structure though, oddly, the book on salvias has the fewest pages in spite of the fact that there are at least twice as many salvias grown as there are snowdrops. All four are attractively designed, accessible, with excellent photography and clear typography. The authors clearly know their stuff, and write well.
The individual entries are similar in their structure, although organized differently, and each book includes 150 main entries – a tiny proportion of the more than 1500 salvias grown in gardens, and around 700 sedums for example. Clearly, many are excluded. In fact there's no entry for the first sedum I look up, the very widely grown ‘Iceberg’.
This prompts the question: are these books intended to highlight the author’s recommend plants, or for gardeners to find information about plants in which they’re interested? It’s definitely the former and of course an expert’s guidance is always valuable but these are books of inspiration not books of reference.
A big issue that these four books fail to address adequately is hardiness. In two of the books, Snowdrops and Dahlias, the USDA hardiness ratings of the plants are not given at all; a significant omission. None of the four provide plant-by-plant hardiness information for British gardeners; the Royal Horticultural Society’s system of hardiness ratings is not included. The publisher tells me it would be “too confusing” to include both the British and the North American hardiness zones. Gardens Illustrated magazine, which sells well on both sides of the Atlantic, don't agree: they include both. The battle to persuade the RHS to adopt the American system (I fought hard!) was lost. The RHS now has its own system for Britain; the RHS zones should be there.
Another thing that puzzles me is awards. The Royal Horticultural Society’s Award Of Garden Merit (AGM) is well known and widely used in Britain and, perhaps unexpectedly, often quoted in North America as well. In the Snowdrops and Dahlia books plants with the AGM are noted, in the Salvia book not only are award-winners not marked but only half the salvias awarded the AGM are included. Salvia x sylvestris ‘Mainacht’ is not noted as the US Perennial Plant Of The Year for 1997. In the Sedums book, some AGM plants are marked and others are not.
It’s great to see this new series of plant books. OK, there are problems. It’s not easy to ensure that plant books work well on both sides of the Atlantic. And, of course, the individual requirements of these different plants should not be forced screaming into a rigid structure. What’s more, the economics of publishing are not at all what they once were and it’s tough for publishers to make a fair return on specialist plant books (tough for authors, too) and these books are issued at a fair price: $24.95/£17.99 before discounts, less for the Kindle editions although the Kindle versions are not available in Britain. Books on tulips, asters, epimediums and ferns on the way.
But it’s unfortunate that the value of so much good information, elegantly and attractively presented and brought to us by wise and experienced plantspeople, has not been matched by a consistent appreciation of the needs of gardeners on both sides of the Atlantic. Still, for gardeners not looking for exhaustive references, these books serve as a wide view into narrow subjects in an engaging and atractive way.
The Plant Lover’s Guides to Dahlias, Snowdrops, Salvias and Sedums are published by Timber Press.
Order The Plant Lover’s Guide to Dahlias by Andy Vernon in North America from amazon.com in both print and Kindle editions
Order The Plant Lover’s Guide to Dahlias by Andy Vernon in Britain and Ireland from amazon.co.uk
Order The Plant Lover’s Guide to Snowdrops by Naomi Slade in North America from amazon.com in both print and Kindle editions
Order The Plant Lover’s Guide to Snowdrops by Naomi Slade in Britain and Ireland from amazon.co.uk
Order The Plant Lover’s Guide to Salvias by John Whittlesey in North America from amazon.com in both print and Kindle editions
Order The Plant Lover’s Guide to Salvias by John Whittlesey in Britain and Ireland from amazon.co.uk
Order The Plant Lover’s Guide to Sedums by Brent Horvath in North America from amazon.com in both print and Kindle editions
Order The Plant Lover’s Guide to Sedums by Brent Horvath in Britain and Ireland from amazon.co.uk
This is not the time of year when we usually think of hostas turning on the color but look at this ‘Paul’s Glory’ outside my window here in Pennsylvania. All summer the golden leaves with their narrow blue-green edges have made an impressive clump but now, as the edges turn yellow and the centers fade to white (as they tend to do in shade), ‘Paul’s Glory’ takes on a whole new look. And it’s not the only one.
Years ago in my garden in Northamptonshire I grew that old favorite ‘Halcyon’ in a terracotta pot (below right, click to enlarge). And every year it turned this lovely biscuit brown in the autumn. The little hardy geranium in amongst it is a self sown Geranium thunbergii. I grew some from seed collected in China but it proved to be a small-flowered weedy ground cover although its autumn leaves take on these attractive tones.
The other hosta I especially like for its autumn display is the oddly named ‘Christmas Tree’ (below, click to enlarge) whose bold puckered leaves are turning a lovely soft yellow now.
Regular readers will appreciate that these all fall in a group of plants for which I have a special enthusiasm - individual varieties which have two different seasons of display. Powerhouse Plants, my publisher insisted on calling them for the book in which over five hundred such plants are covered – some of which actually have four or five different seasons of interest.
And after all, what's not to like about hostas that look wonderful all summer – and then turn a different shade of wonderful in the fall?!
I spotted these “mums” on the left (above, click to enlarge), growing outside the hospital where I’ve been going for my cardiac rehab. They’re replacements for petunias grown in exactly the same way and look like nothing more than a display of footstools outside a furniture store. Although they’re perfectly hardy, they’re treated as seasonal bedding plants and will be replaced when they’re over.
This is one two main ways we see chrysanths here in the US, the familiar alternative is to grow similar varieties as individual specimens in pots, on the front steps perhaps. These, too, will be discarded after a couple of months.
Interestingly, this approach replicates the way plants were grown hundreds of years ago when it was so often the individual plant that was important, and each was allowed space from its neighbor so that it could be appreciated as an individual.
An alternative style is shown above right, where tall single flowered types are planted in a slightly chaotic effervescence of color. As it happens, this much more British way of growing them is seen at the New York Botanical Garden, where all these so far unnamed varieties were developed. But they’re planted so closely together, and so in need of support, that getting in to dead head is impossible.
Personally, I wouldn’t grow them either way. I choose varieties in the same style as those single Korean types at the New York BG, but mix them with perennial asters of various kinds as well as eupatoriums, heleniums, sedums and other late perennials plus shrubs such as physocarpus and euonymus with a long season of fall leaf color. But unfortunately we don't have enough sun here in Pennsylvania for the these sun-loving autumn perennials to thrive, it’s now just too shady.
And while we’re talking about of chrysanths I thought you might like to see these bargain plants I spotted on sale (click to enlarge). Yes, 88 cents – that’s fifty pence. Too cheap, they’re too cheap. No one can make a living from producing plants that sell at that price.
UPDATE: Today, nine days after I took the picture of the footstool chrysanthemums in full color - they look like this (left, click to enlarge). Ghastly.
Nearby - this is at the Pocono Medical Center at East Stroudsburg, PA, where I've been going two or three times week for my cardiac rehab - are plantings of New Guinea impatiens which have been looking good for months.
Today I also spotted some double yellow French marigolds which also look as if they've been there for months are are flowering away merrily.
OK, we can't expect a hospital to grow chrysanths like they do at the New York Botanical Garden. But first there were petunias - which we poor - and then there were these chrysanthemums which were colorful for about a week. The marigolds were surely the best value - by far.
We’ve been here at the house on the lake for thirteen and a half years, and it took my five year old grandson to find an insectivorous plant that we didn’t know we had.
Monty is mad about insects – and so, by association, insectivorous plants. He has pitcher plants growing in their kitchen in the London suburbs. So when he was exploring along the banks of our lake with his dad Carl (below, click to enlarge), he knew a sundew when he saw it because he has some in a pot at home. And he knows what they do to insects. He’s not at all squeamish and watched with interest while I hit the bass his dad caught on the head so we could have it for supper.
So it turns out that we have a flourishing colony of Drosera rotundifolia (above, click to enlarge), the round leaved sundew, growing on the bank of our lake. But they’re growing in an unlikely spot. They’re only a few feet from the water, even now when the water levels are very low, but they’re on an east facing sandy bank where the soil is actually quite dry. Not the soggy sphagnum which we associate with these plants. While there is some moss, some plants are growing in bare sand.
Most of the bank is overhung by low shrubs, so only a five year old is short enough to make his way easily along there and look closely at the plants. But for two or three feet at the point where this colony is happy enough to have produced quite a few seedheads, it’s much more open.
This is a plant that grows all around the world – in a band through the Northern Hemisphere that takes in much of North America, north and eastern Europe and much of northern Russia. In Britain, it occurs mainly in Scotland, Ireland and Wales as well as southern and south west England. It's found scattered across Pennsylvania, in our county (Pike County) it’s recorded from seven sites but surely occurs more widely than that. But it took a five year old to find it on our own property.
Sometimes, people ignore plants simply because they're common. We see them all the time, even growing by the side of the road, and they sink into our subconscious and simply fail to emerge.
What is sometimes called the perennial sweet pea, or everlasting pea, is a case in point. Lathyrus latifolius is easy to grow, we see patches thriving along sunny roadsides in Britain and in North America, and in gardens it may annoy us as it can be uncomfortably vigorous. But it’s very colourful, very productive, clings to fences or shrubs with its tendrils and is a splendid long lasting cut flower. If it were scented there’d be hundreds of varieties.
It’s been used to control erosion in North America, and its ability to prevent the germination and development of shrubs has led to its planting along utility lines to ensure access remains unblocked by shrubby growth. A variety has even been developed, ‘Lancer’, specifically for practical use. It grows more upright than others, has superior seedling vigor, is a good seed producer and also has a better blend of colours than other mixtures.
In a few parts of the US it’s seen as a noxious weed but, on the other hand, the United States Department of Agriculture provides detailed instructions on how best to sow it and grow it when using it for erosion control etc.
In gardens it can be quite a spectacle, and is lovely clinging to a rustic fence or to a robust old shrub rose (right, click to enlarge). There are three basic color forms – magenta, pale pink and white – but, in his book on sweet peas, Roger Parsons lists ten varieties (plus a number of synonyms) although the names are not now applied with much care or precision, especially with regard to flower size. But look for ‘Blushing Bride’ (blushed white), ‘Rosa Perle’ (pink, above - click to enlarge), ‘Red Pearl’ (magenta) and ‘White Pearl’ (white). And if you come across ‘Wendy’s Joy’, with mauve flowers, grow it and pass it round – although dividing the root is the only way to be sure it stays true.
Lathyrus latifolius also makes a long lasting cut flower, with up to a dozen flowers on a spike, and is valuable in itself and also to fill out bunches of scented sweet peas. The challenge is to control the vigor of the beast and encourage it to produce long stems. Training the stems on wires does the trick and tends to create long straight flower stems which are easy to reach for picking.
So next time you notice Lathyrus latifolius flowering by the side of the road (as in Suffolk in eastern England, below, click to enlarge) remember what a fine garden plant it is and look out for the best varieties.
Making the hour’s drive back and forth to my cardiac rehab three times a week, and often walking woodland trails on the other days, I’ve spotted some interesting plants along the way.
A couple of years ago I wrote about a yellow-leaved form of common milkweed, Asclepias syriaca, which I spotted growing by the side of the road and last week in a quiet area at the back of the radiology unit (yes, I was just poking around…) I found a yellow-leaved plant of a different Asclepias species – A. tuberosa, butterfly weed. As you can see (left, click to enlarge) it looks very dramatic and doing very nicely amongst the crown vetch (Coronilla varia).
There were also normal green-leaved plants scattered about the area, which had clearly been disturbed during construction work so we’ll see if that coloring was the freak result of something nasty in the soil or a genuine mutation. I’ll stop back later in the summer for another look.
White flowered monarda
Just at the moment our local wild bergamot, Monarda fistulosa, is in full flower. This seems to be a “first respondent” if you like, one of those plants that quickly arrives in freshly disturbed soil on open sunny sites. It occurs as a few plants or in huge drifts which, when you look closely, include an occasional plant with darker, or paler flowers.
But this week I screeched to a halt as I spotted a plant - just one - with white flowers (abiove right, click to enlarge). It turned out not to be the white flowered species M. clinopodia (which has a few purple spots on the flowers), but a genuine white-flowered form of M. fistulosa (wild bergamot). There were only a few plants in that location, but I’ve marked it and will collect some seed later.
UPDATE That was a few days ago - and yesterday I found another one, twenty miles farther south. I've been all these years and never seen one white one, and now I come across two.
Asian bush honeysuckles
I’d never stopped to look closely at all the shrubby honeysuckles along the roadside (please forgive my severe dereliction of botanical duty), they’re growing along a stretch of road where it’s not safe to stop the car. But they’re quite a sight in May when covered in white or cream or pink or red flowers, and again now when they’re in fruit.
Then in a parking area the other day I spotted a plant with lovely amber orange berries (left, click to enlarge). Frankly, I’m not sure if it’s Lonicera maackii, L. morrowii, L. tatarica, or L. x bella (the hybrid between L. morrowii and L. tatarica) – all of which are collectively known as Asian Bush Honeysuckle; I’ll have to make more of an effort to check them when they flower next year. But, although I know they’re all rated as invasive, they’re very attractive especially those with brilliant scarlet berries (rather than a dull and dirty red) and this pretty amber berried form.
And finally, on the way up the hill to the ledge from which I shot this wonderful picture of a field of Black-eyed Susans (Rudbeckia hirta) – a variegated oak seedling (below, click to enlarge). I think this may be the only one I’ve ever seen outside a botanic garden, and here it is growing by a woodland trail in Pike County, Pennsylvania.
It’s a seedling of red oak, Quercus rubra, and a quick online search for variegated red oaks reveals only ‘Greg’s Variegated’ and one named as 'Foliis Variegatis' in the Journal of Arboriculture in October 1987. It’s growing very near the trail; I may have to move it to the garden in the fall.
The only other one I’ll mention here is the vanishing trumpet vine (Campsis radicans). There are occasional plants all the way along my drive, all with the usual orange flowers. But, last week, I spotted one cluster of purplish red flowers.
There was too much traffic to stop examine it but it turns out this is a known variation - ‘Atropurpurea’ – but very rarely seen. So rarely seen, in fact, that when I did stop a few days later – I couldn’t find it!
I’d read about xHeucherella ‘Copper Cascade’ and it sounded wonderful. A small-leaved trailer or ground cover with rosy coppery gold leaves all the year round. It seemed ideal to cover the bare soil around the edge of one of our dark-leaved Physocarpus opulifolius ‘Mindia’ – known as Coppertina in North America and as Diable d’Or in Europe – with its amber shoot tips.
So when I spotted a ‘Copper Cascade’ in a nursery on my way back from cardiac rehab a few weeks back – I immediately put it in the cart. But I should have looked more carefully. OK, it was in an 8in pot, but when I got to the checkout I discovered, to my shock, that the price of this one plant was – $19.99! (plus sales tax). Twenty bucks! I’m glad my creaky heart could take the shock. For Brits that’s £11.73.
Now, over the years, I’ve more than once said here that plants are too cheap but twenty dollars for one Heucherella is just too much. I’m not sure how much the White Flower Farm branding has upped the price - they have to take their cut, after all – but don’t you think that price is a bit steep?
White Flower Farm are not offering ‘Copper Cascade’ on their website, but the related ‘Redstone Falls’ sells for $19.45 (plus $9.95 shipping) (£17.14) in a 3in pot which is even less of a bargain. Almost thirty dollars for one heucherella in a 3in pot…! Come on, be reasonable…