Alpines and rock plants

After the Chelsea Flower Show

The Diamond Jubilee Award for the best exhibit in the Great Pavilion was awarded to Ashwood Nurseries Image ©Ashwood Nurseries

I wrote about the Philadelphia Flower Show here last year, and ran a guest blog earlier this year about the San Francisco Flower and Garden Show. Now, I’m just back from the granddaddy of them all, the Chelsea Flower Show.

Well, I remarked on the poor light in the exhibition center at Philadelphia, the shortage of actual flowers was a feature at San Francisco and the surfeit of irrelevant trade stands was noted at both – no such problems at Chelsea.

Chelsea is about plants and gardens and the trade stands reflect that pre-occupation. There were seventeen outdoor show gardens (and the minimum size is 10m x 10m), thirteen smaller outdoor show gardens, and a generous helping of outdoor trade stands designed as gardens as well as garden-related sales booths. No booths promoting river cruises or kitchen gadgets or miracle cures.

In the three acre Great Pavilion, a bright, modern structure that replaced the vast canvas tent a few years ago, were one hundred and three floral exhibits staged by nurseries, growers, florists, specialist societies, horticultural colleges and scientific institutions.

Vast billows of roses, walls of phalaenopsis, cottage style perennial plantings, cacti, a whole stand of perhaps a hundred different miniature hostas (I lost count, I’m afraid), fragrant hyacinths, luscious strawberries ready to pick, strings of tempting cherry tomatoes and so much more. Daffodils were at their peak, dahlias were in full flower - a surprising duo and neither looked forced.

The Diamond Jubilee Award for the best exhibit in the Great Pavilion was awarded to Ashwood Nurseries for their stunning exhibit of hepaticas (above), they showed all twelve species together with a range of hybrids including some developed at Ashwood.

It’s a lot to take in but you can see the plants and gardens at the Show (and see how the show comes together in the three weeks running up to the opening) from home, check out this page of videos on the Royal Horticultural Society website.

I wrote about the Chelsea Plant of The Year competition in The Telegraph and blogged every day for my Plant Talk blog for Mr. Fothergill’s.

I’ll also again be writing up the Chelsea Plant of The Year competition for the RHS magazine The Plantsman.

And I'll be discussing the Chelsea Plant of The Year winners here soon.

A Tale of Two Corydalis

Corydalis solida 'Blushing Girl' Image
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 and available in North America from 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 Corydalis incisabe 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.

Free online magazine for rock gardeners

The cover of the January 2013 International Rock Gardener features Galanthus 'Grake's Gold'For most readers of Transatlantic Gardener, spring is here or it’s on the way – and, in spring, a gardener’s attention turns to… rock plants. And for the serious alpine plant nut, there’s nowhere more interesting to go than the International Rock Gardener magazine.

This free – yes, free (but donations welcome) – monthly online-only magazine is published jointly by the Scottish Rock Garden Club and the Czech Prague Rock Garden Club and features authoritative yet very readable articles about rock plants and alpines of all kinds.

I was especially struck by the issue from January this year which is entirely given over to a review of Eranthis – the best known of which is the winter aconite, Eranthis hyemalis, an invaluable early bulb. What a revelation to see so many lovely forms! You may be surprised to see that some are white (below, click to enlarge).

Recent issues have featured the orchids of Crete, rock garden White-flowered Eranthis pinnatifida featured in the January 2014 issue of The International Rock Gardenerconstruction, plant hunting in China and in Turkey and in other intriguing locations, botanical issues are explored, and bulbs are frequently featured. And everything is presented in way that suits readers all over the world.

It’s also very important to say that the photography is outstanding – and there’s plenty of it.

It’s only realistic to say that International Rock Gardener is not for real newcomers to rock gardening; it assumes a little knowledge of the subject and some of the plants discussed are not easy to obtain - although those tempting pictures will excite even the most basic novice. But this is a valuable window on the serious world of alpines and features many fine plants that most gardeners don’t even know exist.

And all you have to do is go to the International Rock Gardener page where you can download pdfs of every monthly issue going back to January 2010. And why not make a donation while you’re there?

* The snowdrop on the cover, by the way, is ‘Grake’s Gold’, the aconite is Eranthis pinnatifida.

Powerhouse Plant For All Seasons: Cyclamen coum

Cyclamen coum 'Maurice Dryden'. Image ©GardenPhotos.comTime for a look at another Powerhouse Plant, these are Plants For All Seasons - individual varieties which bring colour and interest to the garden for at least two seasons of the year. I feature over five hundred of them in my latest book, Powerhouse Plants, and every month in Gardeners' World, Britain’s top-selling garden magazine (and also available in the US) I focus on one very special Plant For All Seasons, highlighting three features of a single variety that bring color to the garden at different times of the year. This month, in the magazine, I feature Spiraea ‘Goldflame’ and next month it’s the lovely but long-winded Polygonatum odoratum var. pluriflorum ‘Variegatum’.

And every month or two, here on my Transatlantic Gardener blog, I bring you details of another Powerhouse Plant this month it’s Cyclamen coum (left, click to enlarge).

This unexpectedly tough little plant from Turkey and the Caucasus (hardy to z5, -29C) has two special features. First there are the small, neat, rounded, rather leathery leaves. These can be beautifully silvered, with or without a green edge, but in some cases are a rather dull uniform green – of course, choose the former. They emerge in the autumn and are followed in winter and spring (depending on the climate) by flowers made up of five reflexed petals held above the leaves on individual stems; in some cases, the flowers are attractively scented.

The flowers come in a range of colors from pure white through various pink shades to magenta and including some lovely bicolors like this one (above, click to enlarge) which is ‘Maurice Dryden’ whose pinkish red stems are another highlight.

So, with its long season of silvered foliage partially overlapping with its small colorful flowers, this is an easy and reliable little plant for a shady or partially shaded site and preferably in rich but well-drained soil. In fact this one of the easiest of all garden cyclamen and usually self sows once established. It’s lovely under hellebores with wild crocus such as C. tommasinianus.

There many varieties of Cyclamen coum, and they all set out in Chris Grey-Wilson’s excellent book Cyclamen: A Guide for Gardeners, Horticulturalists and Botanists (available in the UK and also in the US). Varieties to look out for include ‘Maurice Dryden’ (above) and ‘Silver Leaf’ although some nurseries sell them under descriptive names such as “Silver/Pewter Leaves, White Flowers”.

In North America you can order Cyclamen coum from Edgewood Gardens and in Britain you can order Cyclamen coum from Potterton’s Nursery.

North American readers can find out more about Powerhouse Plants here.

British readers can find out more about Powerhouse Plants here.

Plant Of The Century

It’s a hundred years ago this year, in 1913, that the most famous flower show in the world, The Chelsea Flower Show, was first staged and to mark the centenary of the show the Royal Horticultural Society is asking gardeners to vote for the Plant Of The Century.

They’ve chosen a plant from each decade, and each is introduced on video by a gardener of the appropriate generation - from a 92 year old ex-paratrooper to an eight year old schoolgirl. Anyone can go online and vote for their favorite. These are the plants.

Saxifraga ‘Tumbling Waters' (1913-1922)

Pieris formosa
var. forrestii (1923-1932)


Russell hybrids (1933-1942)

Rhododendron yakushimanum

Rosa Iceberg (‘Korbin’) (1953-1962)

Cornus ‘Eddie’s White Wonder’ (1963-1972)

‘Bowles's Mauve’ (1973-1982)

Heuchera villosa ‘Palace Purple’ (1983-1992)

Geranium Rozanne (‘Gerwat’) (1993-2002)

Streptocarpus ‘Harlequin Blue’ (2003-2012)

Not everyone is happy with this list, I have to say. As one Royal Horticultural Society insider (who had better stay nameless) has already emailed me: “Typical RHS, they’ve ignored all the annuals and patio plants that people actually grow and included two shrubs that only grow on acid soil which most of the country doesn’t have.” Hmmm… Got a point, there…

Me? I’d probably vote for Iceberg rose although now that the sulfurous pollution that kept mildew and blackspot at bay in the 1950s is gone it’s a martyr to disease. Or the Russell lupins. But I think Geranium Rozanne will probably win, especially as the nursery that sells it has its PR firm campaigning on its behalf.

Click on the images to see each one enlarged. Check out all ten plants on the Plant of The Century webpage, or click the plant links above to see details of each plant an cast your vote. Voting closes at 12 noon BST Friday 24 May, 2013. Which do you think is Plant Of The Century?







Taking advantage of walls

Stone walls are a big feature in our little town in Northamptonshire. The local limestone is used extensively for building and with the soft mortar that often goes with it, the result is a great habitat for plants.

A year or two back I mentioned the fern growing in a wall behind the supermarket, but walking round town before I returned to the US turned up quite a few plants taking advantage of this habitat.

The mahonia growing through the low wall (above, click to enlarge) demonstrates the power of its creeping roots as it penetrates through 15in/38cm of limestone wall, and in this case the wall is built with very hard mortar. Planted in the border on the inside of the wall, it’s made it way straight through the wall and is now flourishing on the outside.AubrietaWall_JWW9731

Aubrieta (right, click to enlarge) is an old limestone wall favourite and here two seedlings have germinated together and are flowering in slightly different colours. In turn these have seeded and young plants are now becoming established in the soil at the base.

Just around the corner from the aubrieta I spotted a lovely flowering plant of white comfrey, Symphytum orientale, growing in a wall, about 5ft/1.5m above the ground. But when I returned with the camera, someone had torn it out.

AspleniumRoof_G021510Then another fern, growing just under the gutter about 15ft/4.5m above ground. Where two lengths of gutter join there’s just enough of a leak to moisten the mortar at the top of the wall and allow the maidenhair spleenwort, Asplenium trichomanes, to settle in.

Other plants I've spotted growing in walls around town include Helleborus foetidus, with the seed secreted away in the cracks by ants; wallflowers in various reds and yellows turn up in quite a few places; California poppies, Eschscholzia, in orange and cream; Campanula persicifolia, in blue and in white. Just to mention a few...

Fleuroselect Gold Medal Winners for 2013 – already!

Well, no sooner do I finish my round up of the All-America Selections and Fleuroselect Gold Medal winners for 2012 than Fleuroselect announces its winners for 2013! And, what’s more, Fleursoselect has abandoned its policy of only giving medals to seed-raised plants, the dahlia is raised from cuttings. For more on All-America Selections and Fleuroselect, see my earlier post.

So, the three 2013 Fleuroselect Gold Medal winners are: Lewisia 'Elise', Dahlia ‘Dalaya Yogi’ and Celosia 'Arrabona'.

Lewisia cotyledon 'Elise' - Fleuroselect Gold Medal Winner 2013

Lewisia 'Elise'

This new lewisia (above, click to enlarge) has three main points of interest. The mixture of colors is lovely – soft and vivid pinks, salmon, orange, white, yellow and almost purple plus some lovely bicolors.

Also, unlike other lewisias, it does not need a cold spell to initiate flowering so it will bloom in its first year. And, finally, its seed has a higher rate of germination that other lewisias, about 80%, so you’ll get more plants for your money. Sow in January or February to flower in summer.

Search for suppliers in the USA (none yet)

Search for suppliers in the UK (none yet)

Celosia 'Arrabona' - Fleuroselect Gold Medal Winner 2013Celosia 'Arrabona'

Developed in Hungary, the feathery plumes of Celosia 'Arrabona' (left, click to enlarge) come in a shade of orange red that the Fleuroselect judges thought was unique. Reaching about 14in/35cm in height, 'Arrabona' can be used as a garden annual, in containers, or as a cut flower. It also enjoys summer heat, is drought tolerant once established, and is very prolific.

In Britain, the recent trial of celosias at the RHS Garden at Wisley revealed how well these plants do in the contemporary British summer climate. And it enjoys that hot summers across much of North America. Sow in February from flowering from July to October.

Search for suppliers in the USA (none yet)

Search for suppliers in the UK (none yet)

Dahlia ‘Dalaya Yogi’

This new dahlia is the second in the series of medium sized dahlias for containers and summer borders. Dahlia 'Dalaya Yogi' - Fleuroselect Gold Medal Winner 2013 The bushy plants develop these attractive, dark-eyed, semi-double flowers (right, click to enlarge) which open early and continue until the frosts. And they open continuously right through the season, not in flushes with quiet periods in between as some dahlias of this type do.

Plants are also tolerant of powdery mildew and at about 16in/40cm in height are small enough for containers, but not so dwarf as to lack elegance.

Search for suppliers in the USA (none yet)

Search for suppliers in the UK (none yet)



Book Bullet: Auriculas Through The Ages

This is the first in a more or less regular series of short book reviews, Book Bullets, which will feature here on Transatlantic Gardener, between other posts, especially in the run-up to the Holidays.

Auriculas - Book ReviewBased around the exquisite RHS Gold Medal winning paintings of Elizabeth Dowle, sixty in all, this intriguing overview of the history of the auricula takes us through the development of these captivating flowers from the wild through their heyday to their present revival.

Packed with fascinating historical detail that informs our pleasure in auriculas today, yet written in a relaxed and accessible style which is not overpowered by the wealth of material, this is an enjoyable and informative book.

Don’t expect a comprehensive A-Z of varieties, you can find that elsewhere, and don’t be put off by the sometimes clunky typography. Take pleasure in this readable history with its delicately beautiful paintings.

  • Superb illustrations by Elizabeth Dowle
  • Enjoyable overview of a fascinating history

Auriculas Through The Ages by Patricia Cleveland-Peck, illustrated by Elizabeth Dowle, is published by Crowood Press.


Phlox: a splendid new book for naturalists

Phlox paniculata. Image © (all rights reserved)
The phlox are blooming and I have questions about them…. lots of questions, mainly about the tall American native Phlox paniculata, a classic British border perennial. So I turn with a relief to a new book on the subject Phlox: A Natural History and Gardener's Guide by James H. Locklear (Timber Press).

I'm looking for an expert's opinion:
* Why is P. paniculata 'David' no longer mildew resistant, was 'David's Lavender' ever resistant?
* I'm wondering if the many recent much shorter varieties from Holland are forms of P. paniculata or hybrids – and if they're hybrids, do they spread more, as we might expect (one parent does, the other not) and do they still get eelworm (again - one parent usually does, the other not)?
* What's the best way to take root cuttings and so avoid eelworm? Many home gardeners have problems with this eelworm-avoiding technique?
* Lots of ID confusions… Is 'Blue Paradise' the same as 'Blue Evening', for example, or is one being sold as the other?
* Do some varieties respond better to cutting back in May than others – so they flower on shorter plants and don’t need staking?

Phlox: A Natural History and Gardener's Guide by James H. Locklear (Timber Press) ISBN: 9780881929348l But it turns out that it's not that sort of book. This is an impressive and authoritative botanical work, with detailed descriptions of all the wild Phlox species. The wild distribution of each species is discussed, there are many details on the habitats of the plants at different sites, and invaluable accounts of the plants with which each species is associated – something rarely found in this detail in plant monographs and testament to the author's ten years of diligent research.

But, although enjoyably written and comprehensive when dealing with plants in the wild, the book answers none of my questions. Few cultivars of any species are mentioned, eelworm gets less than three lines, there is little on propagatrion, and cultivation advice is generally basic.

That would be fine, if there was also a book on Phlox for gardeners. But there's not. And I know from experience that once one book on a specialist plant subject has appeared – good or bad, comprehensive or not – it's very tough to persuade a publisher that another is needed.

Phlox: A Natural History and Gardener's Guide is a superb Natural History - but, sadly, not so hot as a Gardener's Guide.


Alpines and bulbs but not blogs

BulbLogpage597 We’re overrun with blogs these days. A few of the best are listed on the right but a couple which do not, perhaps, get the notice they deserve are hosted by the Scottish Rock Garden Club (SRGC).

The Bulb Log Diary is written by Ian Young, the President of the SGRC, and he posts on bulbs in detail and with superb photography about every two weeks. He grows an extraordinary range of small bulbs, and writes about them and photographs them with care and thoughtfulness.

Also, from the Royal Horticultural Society’s garden at Wisley in Surrey comes the Wisley Alpine Log written by Paul Cumbleton who runs the Alpine Department there. This provides a fascinating insight into the work and development of Wisley’s alpines and is well worth following.

Ian’s most recent entries are on tulips and especially on fritillarias, and then on corydalis revealing their extraordinary variety. Paul’s recent additions have been on the creation of new planting areas on the Wisley rock garden for hardy (zone 8) carnivorous plants and on hepaticas and other mid-March alpines.

They’re always interesting, always a good read – even for gardeners who never grow alpines or dwarf bulbs - and some of the photography is spectacular.

HepaticaHarlowCarrpage But here’s the problem: they’re not actually blogs. For some reason they’re formatted as pdf files so there’s none of the interactivity we expet from blogs. They display in the web browser and can easily be downloaded but you can’t comment about them on the spot, you have to go to a separate forum to which there is no link. In fact it’s impossible to go anywhere else except back to the contents list. There are no links on the pages at all.

This is such a shame, the unusual format is a definite deterrent going back regularly and to posting comments. We’re all so used to RSS feeds and just clicking on the Comment link at the end of a post to add our thoughts that I’m sure the SRGC miss out on many readers by using this approach.

However, in spite of all this, my recommendation is to go take a look. Regularly.

Go to Ian Young’s Bulb Log Diary

Go to Paul Cumbleton’s Wisley Alpine Log