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October 2010

September 2010

Back in PA for a fiery (invasive) treat

Decodonverticillatus17738 Many garden treats awaited me back in our Pennsylvania garden on my return from England, the asters and ipomoeas are amazing, plus one mass of color down on the lake shore which I could see gleaming through the trees. The lakeside was lit up by fiery foliage (click images to enlarge).

And this is not a fallen maple or the foliage of a familiar fall-coloring tree. This is a local native perennial called the swamp loosestrife, Decodon verticillatus. Related to the European invasive the purple loosestrife, swamp loosestrife is a vigorous colonizer along the shore, its reddish arching stems rooting wherever they touch the mud.

In fact it’s a bit of a menace. It grows in wet mud along the bank and spreads out into very shallow water where it makes a tight mass, collects silt, and ends up reducing the extent of the open shallow water that small fish and so many insects enjoy. In recent years I’ve been pulling it out to retain that shallow open water that our many species of dragon flies and damsel flies appreciate. But with the lake so low this year, it’s spreading fast across the newly exposed mud.


But at this time of year it’s fiery fall foliage is quite a sight. Earlier in the season clusters of showy pink flowers line the branches. Ducks east the seed capsules and muskrats eat the fleshy roots and stem bases.

If not for its worrying vigor I’d be suggesting Decodon verticillatus for ponds and lakes back in Britain. In fact just one British nursery seems to sell it – and doesn’t mention its vigor. Perhaps in cooler British summers it’s more restrained.

But it’s interesting that while its European relative is universally derided, the invasive tendencies of this local native go unremarked.

That red rudbeckia – ‘Cherry Brandy’

Rudbeckia,Cherry Brandy,red, Image © (all rights reserved) Last summer Clint posted this comment about Thompson & Morgan’s Rudbeckia ‘Cherry Brandy’, the first red rudbeckia: “I love your site and would like to know if you would be informing your readers about the disaster known as Rudbeckia ‘Cherry Brandy’. I planted seeds of this and they are UGLY… Everyone is laughing about this much-hyped plant at Dave's Garden. Nobody I know has a bloom that looks like the photos used to sell them.” I heard similar comments from other people.

Well, as I rushed to a meeting through the RHS garden at Wisley near London the other day I passed some plants of ‘Cherry Brandy’ – and they looked great. A really lovely colour. Here’s my quick snap. I saw it looking impressive in a suburban front garden recently, too, while stuck in the traffic. And today the images posted over on Dave’s Garden also mostly look pretty good.

So while some people were certainly disappointed last year, Rudbeckia ‘Cherry Brandy’ does seem to be a valuable new colour break.

You can find out more about Rudbeckia 'Cherry Brandy' over on my RHS New Plants blog.

In North America you can order seeds from Thompson & Morgan.

In Britain you can order seeds or you can order young plants from Thompson & Morgan.

Autumn fruits confirm an old wive's tale?

Pyracantha,berries,fruits. Image © (all rights reserved) People often say that an autumn in which branches are weighed down with fruits and berries is a sign, a sign of a hard winter ahead. It's one of those old wive's tales that many people embrace, but those of us with a scientific bent tend to refute. And, in this case, of course, it's is nonsense. How does a pyracantha (left, click to enlarge) know that it’s going to be unusually cold six months after flowering?

No, a fruitful autumn is a sign of a sunny and frost free spring earlier in the year. And as I’ve been driving around the south of England this last two weeks, it’s been obvious that again spring blossoms were undamaged by frost, that pollinators were plentiful and that the mix of sun and rain this autumn has ensured that the crop is indeed prolific.

In hedgerows, the blackberries are weighing down the branches (right, click to enlarge);  Blackberry,blackberries,Rubus,fruticosus,berries,fruits. Image © (all rights reserved) the scarlet hawthorn berries sparkle in the sun; the misty blue sloes line the branches of the blackthorns. Seedling crab apples and eating apples shine bright along the motorway.

In gardens, the pyracanthas are so crowded with berries - scarlet, orange and yellow – that the branches bend under the weight. But that’s not all due to the spring weather. Recently introduced disease-resistant varieties, like those in the Saphyr Series, are now much more widespread so good crops of fruits are more likely, even in bad years.

Quince,Cydonia,fruits. Image © (all rights reserved) Apples, plums, soft fruit, even the enormous quinces I spotted in a suburban front garden (left, click to enlarge). Quite a crop. But.

An email from a Latvian friend here in Northamptonshire reads: “Just read the first prognosis on a Latvian site from Polish meteorologists about the forthcoming winter. They argue that due to the significant weakening of the Gulf Stream the arctic air mass is going to penetrate into Europe for a prolonged period and produce one of the coldest winters ever. Time to open a ski shop!”

So, as it turns out, this abundance seems perfectly timed to help the birds through an unusually icy winter. Are we sure that nature doesn’t know more than we do?!

My latest work online

Here are links to a few of my pieces which have appeared on the Royal Horticultural Society website recently.

Ten soft fruits which have received the RHS Award of Garden Merit

Ten dwarf spring bulbs that have received the RHS Award of Garden Merit

Check out all my selections of AGM plants

Latest Award of Garden Merit plant - Cortaderia selloana Silver Feather ('Notcort')

Check out all the latest AGM winners I've written up

One ten plant choice, and one plant which has recently received the AGM goes live on the RHS website every month.

The blues...

Today, while I'm in England, a guest post from my wife judywhite back in Pennsylvania. Thanks, judy.

Ipomoea,Heavenly Blue. Image © (all rights reserved)Sometimes serendipity in the garden isn’t really just coincidence. I’ve realized that our garden has become furiously dotted with blue. It was a subconscious thing, this gradual adding of plants with blue flowers and/or blue foliage. Oh, okay, some of it was serendipitous, since a few of the plants were sent to us, dare I say it, out of the blue, for trialing. Blue is supposed to be such a rare horticultural color. Hey. It’s not.

Out there today, shining even in the blue of this rainy, gloomy gray day where we’re stuck halfway between the end of summer and the beginning of fall, are four blue showstoppers. First, of course, is the great mass of annual ‘Heavenly Blue’ morning glories (above, click to enlarge), climbing the picket fence, where I constantly have to unwind the latest tendrils from the gate so that they don’t break off when the UPS guy comes. Then Caryopteris,Sunshine Blue, Image © (all rights reserved) there’s a big shrub of Caryopteris ‘Sunshine Blue’, much happier now that the old cherry trees are gone above it, even if the gold in the leaves isn’t as pronounced as earlier in Ceratostigma,willmottianum, Image © (all rights reserved)the season. In the shade is groundcover Ceratostigma plumbaginoides, a lot of bright bang for the size. And right out the front door is the 2ft/60cm tall mound of tiny blue starry asters that we’ve lost the tag of; that plan of burying all the labels conveniently at the front of the raised beds sometimes doesn’t work as well as you might think.

 Still going, if more sparsely since their early big flushes, are two low-growing spreaders, Lithodora diffusa ‘Grace Ward’ (I like its solid blue much better than the more common blue and white ‘Star’) and Campanula portenschlagiana 'Blue Waterfall', both first-timers this year. Hydrangea Endless Summer has faded to a violet blue from its former intense brightness, but the blue kale is still going strong, plus we pull off leaves and have soup anytime we want. More blue foliage is in the fabulous Hosta ‘Hadspen Blue’, utterly slug-proof and well behaved. There are hints of blue in the Japanese painted ferns and the Meserve hollies ‘Blue Girl’ and ‘Blue Boy’, and in the fading Phlox paniculata ‘David’s Lavender’, whose flowers turn more blue as they get older - makes me think aging might not be all bad after all.
Hosta,Hadspen Blue, Image © (all rights reserved) I think this blue streak started with the forget-me-nots that the previous owner left behind over 10 years ago; I’ve been encouraging them everywhere, and they shatter through in spring. Oh! And then there’s the icy blue of Amsonia tabernaemontana, and the darkness of that Aquilegia that started out as ‘Blue Bunting’ but seems to be something else entirely now, and the blue flowers of Ajuga reptans ‘Burgundy Glow’ against the purple and green and cream leaves, and the baby softness of Iris ‘Color Me Blue’, and the startling spikiness of Clematis ‘Blue Fountain’ and…

I want more.

And I love punctuating the blue with yellow. Hmmm, let’s see, we need more of that too…

Our chestnuts are dying

Aesculus,hippocastanum,horse chestnut,leaf miner,Cameraria ohridella. Image l© (all rights reserved) As the plane from New York approaches Heathrow airport, look out of the window and the horse chestnut trees (Aesculus hippocastanum) are easy to spot. Not, as my mother insists, because they’re the first tree to develop autumn colour – although coming in to land in September that might at first seem to be the reason.

No. Just about every horse chestnut tree in the south of England has turned brown because it’s infested with a pest, the horse chestnut leaf miner (Cameraria ohridella). This little bug tunnels through the leaves causing translucent patches - in the same way as the leaf miners infesting chrysanthemums or aquilegias. But the tunnels soon merge, the leaf turns brown, the edges roll up, then the leaf drops off. By August, some trees have lost all their foliage. After a few years of losing all their leaves, trees die.

First noticed in south London in July 2002, trees across most of south and central England are now infested. It’s spread very rapidly and continues to spread. There is no effective control. Other species of Aesculus, plus Acer platanoides and A. pseudoplatanus, are also damaged.

Aesculus,hippocastanum,flowers,horse chestnut. Image licensed under the Creative Commons Attribution-Share Alike 3.0 Unported license.	
© Andrew Butko In Britain, the horse chestnut is an iconic tree. Its bold foliage opens from fat, sticky winter buds, then the dramatic spring flowers are followed by conkers, large shiny nuts used in kids games. The World Conker Championships are held, this year on 10 October, just a couple of miles away from where I’m writing this. Aesculus,hippocastanum,fruits,conkers. Image licensed under the Creative Commons Attribution-Share Alike 2.0 Generic license. Photograph © Andrew Dunn.

But – the horse chestnut is not a British native tree. It grows wild in Greece and Albania and was first brought to Britain in the early 1600s. It’s so common that some American observers would probably classify it as an alien invasive and would be delighted that the leaf miner is killing trees. By contrast, in Britain research is continuing to find a predator that will kill the leaf miner.

First it was the English elm, now the horse chestnut. But things change. Last year, in Northamptonshire a few miles from here, there were elm trees growing in the hedgerow that reached about 4.5m/15ft high. And on the south coast, there were many trees that were never infected. But things change again, and now those trees are again under threat.

Aesthetically and culturally the loss of so many of these trees is a disaster. But the horse chestnut has only been in this country for 400 years, the elm for 2000 years - not long, in the evolutionary life of a tree species. And things will continue changing.

Chipmunks: pests and pleasures

Chipmunk,eastern, Tamias striatus. Image ©Gilles Gonthier. License: Creative Commons Attribution 2.0 Generic Generally speaking, chipmunks are delightful. It’s a treat to see them around the garden even though, sometimes, it’s necessary to rescue them from the jaws one of our cats (scroll right down – to see the cats, not the chipmunks in jaws…). In fact, our cats don’t catch very many as they’re just so quick, and of course they can climb. Seemingly indigestible mice are favored.

But a few years ago, after a winter under the snow, I noticed that one of our newly planted choice hellebores (a double black, I vaguely seem to recall) had died after its roots were tunneled through and eaten. [Can’t have been much fun for the chipmunk, hellebores are poisonous.]

ChipmunkHole17523 And this summer I was wondering why the Rudbeckia laciniata I’d moved along the back of the border into more light was doing so badly. When the foliage in front fell to one side it became clear: there’s obviously a burrow under there (left, click to enlarge). And it’s probably stuffed with all the sunflower seeds they’ve stolen from the bird feeder.

No chipmunks in Britain, of course, though a few people keep them as pets, I’m told. But they’re such a treat, I think we can live with an occasional plant casualty.

New variegated sage update

Salvia,sage,variegated,La Crema,Berggbright. Image: © All rights reserved. Back in the spring, I mentioned what looked to be one of the highlight new plants of the season, the variegated culinary sage Salvia officinalis La Crema™ (‘Berggbright’). At the time, all we had were three young plants, from the US Culinary Couture™ brand from Hort Couture™, just being planted out.

Well, it’s now September – how are they doing?

Two of the plants have done well, one in a container with some calibrachoas, which are doing rather less well, and the other in the border – both in the sun for most of the day. They’ve made plants as wide, perhaps a little wider, than they are tall and their coloring is delightful and consistent.

And the foliage is not too variegated, enough to create an attractive color pattern, but not so heavy as to overdominate the plant and weaken its growth. And no reversion so far. The third plant faded away through no fault of its own, I think it just became overshadowed by its all-too-luxuriant neighbors.

Just to remind you, this is a new variegated form of the well known, broad-leaved sage ‘Berggarten’. It turned up in a garden in Virginia in 2007 and has been in US retail stores this year sold under the trademarked name La Crema™. Its cultivar name in ‘Berggbright’. Unusually, the plant is not protected so anyone can sell it as ‘Berggbright’. As far as I know no one in Britain or the rest of Europe has it yet – a great opportunity for someone.

Now, let's see how it survives the winter...

I won an award!

Graham Rice,award,PPA,Perennial Plant Association,International Contributor Award. Image © (all rights reserved) Yes, I’m delighted to report that I’ve won an award from the Perennial Plant Association (PPA). This is the society of mainly professional growers and plantspeople based in the USA and devoted specifically to perennial plants. And they’ve just honored me with their International Contributor Award for 2010. Thank you.

(How else do I illustrate my award, except with a picture of the plaque?! Click to enlarge.)

This award honors an individual who has made significant contributions to the herbaceous perennial industry through writing, breeding, growing, retailing, or designing with perennials.

Other winners in the past have included such notables as Piet Oudolf, Adrian Bloom and Beth Chatto.

Thank you, PPA. I’m honored.

Here’s a complete list of winners from previous years:
David Tristram - Plant breeder (UK)
Georg Uebelhart - Jelitto Seeds (Germany)
Poul Peterson - Overdam Nursery (Denmark)
Nico Rijnbeek - Rijnbeek & Sons Nursery (Netherlands)
Beth Chatto - Plantswoman, writer, nursery owner (UK)
Gert Fortgens - Arboretum Trompenburg (The Netherlands)
Ernst Pagels - Pagels Nursery, Leer (Germany)
Jac DeVroomen - DeVroomen Nurseries (The Netherlands)
Adrian Bloom - Plantsman, garden designer, writer, nurseryman (UK)
Piet Oudolf - Plantsman, garden designer, nursery owner (The Netherlands)
Luc Klinkhamer - CNB (The Netherlands)