This is my third monthly piece about Powerhouse Plants, Plants For All Seasons which don’t flare and fade with two weeks of flowers and fifty weeks of boring leaves. These are plants which provide color and interest for at least two seasons of the year and not just a quick flush of flowers. So when you look at a plant in flower at the nursery or in a catalog, always ask: What else does it do?

My new book, Powerhouse Plants, includes details of over five hundred plants that do something else at another season. And every month in Gardener’s 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 which bring color to the garden at different times of the year. And every month here on my Transatlantic Gardener blog I bring you details of yet another – this time, Kolkwitzia amabilis Dreamcatcher (‘Maradco’).

Basically, this is a much improved version of a familiar beauty bush, Kolkwitzia amabilis, which flowers for just a few short weeks in late spring and early summer. Dreamcatcher adds months of fascinating changing foliage color.

In spring, the new shoots are coppery red, then the foliage turns yellow as it matures. Later, it becomes chartreuse with gold hints through summer and in the autumn, and it changes again becoming orange and gold in a final fall flourish.

In my experience Dreamcatcher also makes a lower, more spreading plant than ‘Pink Cloud’, the usual form seen, and the larger of our two seven year old specimens is about 3ft/90cm high and noticeably wider. More widely grown in North America than in Britain, British gardeners should hunt it out.

You can read more about Kolkwitzia amabilis Dreamcatcher (‘Maradco’) in a blog post here back in 2010.

Please take a look at Plants For All Seasons in Gardeners World magazine each month. And check back here for occasional posts about other Powerhouse Plants – the Plants For All Seasons.

You can order my book, Powerhouse Plants in Britain from amazon.co.uk

You can order my book, Powerhouse Plants in North America and the rest of the world from amazon.com

 Or you can find out more about the book at the Powerhouse Plants webpage.

 Subscribe to Gardeners' World magazine

The winner of the Chelsea Flower Show 2013 Plant Of The Year was announced late on Monday. The award goes to Mahonia eurybracteata subsp. ganpinensis 'Soft Caress'. A selection of a Chinese species, made in Georgia, I feature it on my Royal Horticultural Society New Plants blog in September last year. This is what I said:

Mahonias are amongst the most impressive and dependable of flowering shrubs – but they have a problem. They’re spiny, sometimes viciously spiny. Not any more.

Mahonia eurybracteata is a modestly sized evergreen shrub that grows wild in five provinces of south west China. Reaching 3-4ft/90-120cm in height, and about as wide creating a more or less rounded plant, the long slender divided foliage is slightly greyish green, soft to the touch and not at all spiny or holly-like as so many varieties are.

From August until October the flowers appear, upright clusters of spikes at the tips of the shoots are lined with slightly fragrant, bright yellow flowers that last for many weeks and are followed by blue berries.

‘Soft Caress’ is a new form selected for its extra hardiness and for foliage which has a more noticeably silvery sheen. The leaves may also take on reddish tints as the days shorten and the nights become cooler. ‘Soft Caress’ is neat enough to be grown in a container, or is happy in a sunny or partially shaded border where it appreciates fertile, but well-drained soil.

‘Soft Caress’ was selected by Ozzie Johnson and Karen Stever from a group of seedlings of Mahonia eurybracteata grown at ItSaul Plants in Chamblee, Georgia.

In Britain you can order Mahonia eurybracteata ‘Soft Caress’ from Crocus and from Gardening Express.

In North America you can order Mahonia eurybracteata ‘Soft Caress’ from Wayside Gardens and from Springhill Nursery.

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)

Lupinus Russell hybrids (1933-1942)





Rhododendron yakushimanum (1943-1952)





Rosa Iceberg (‘Korbin’) (1953-1962)





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











Erysimum ‘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?

 

 

 

 

 

 

I mentioned a couple of weeks ago how I’d been reading this book, by flashlight and candlelight, when the power was out during the storm. But I’d also been using it as regular reference for some time before that. And a big fat reference book needs time to prove its value.

This is a huge, large format book, generally with three or more pictures on each page – often with more pictures than text. Set out as an A-Z by genus, the entries are written in accessible language with the minimum of botanical terminology with thoughts on culture and use integrated with the descriptions.

As ever with Mr Dirr, the text is very readable partly because through his decades of research he has never taken anything for granted, but always looked and thought and then decided - and all that is in evidence here. There is also a welcome emphasis on newer introductions. Thank goodness for his prodigious note-taking and/or his prodigious memory.

But the problem with covering trees and shrubs for all climates in one book is that, well, it’s impossible to do so comprehensively. For example, choosing two genera which are very important to British gardeners – the book is of course published in Britain as well as the North America - Erica gets just two pictures and one column of text, while Hebe gets two pictures and half a column of text. American readers will appreciate twenty pages of hollies (but only a page and a half is devoted to those mainly grown in Britain) and Lagerstroemia, important in the US, gets seven pages (they're hardly grown in Britain at all). Strangely, Salvia is excluded altogether.

It’s a bold enterprise, publishing a 950 page full colour book on trees and shrubs. But it makes up for its gaps with its intelligent opinions, excellent illustrations and Michael Dirr’s breadth of experience and insight.

Dirr’s Encyclopedia of Trees and Shrubs by Michael A. Dirr is published by Timber Press at $79.95/£50.00

• An easy read, pleasingly opinionated and packed with information
• Very well illustrated
• Welcome focus on recent varieties
• Plants for American gardeners are dominant

OK, two new reblooming lacecap hydrangeas. Reblooming lacecaps? Great. One is pink, the other is blue. Ideal. They’re called Hydrangea macrophylla (Flair&Flavours) Cotton Candy ('MAK20'), that’s the pink one, and Hydrangea macrophylla (Flair&Flavours) Blueberry Cheesecake ('MAK20'), that’s the blue one. (Left, click to enlarge.) OK, their names are a little heavy going but it sounds as if they’d make a very pretty pairing in the garden, they tend to be semi-double, too. Both are offered by the top-rated UK mail order nursery Crocus.

The problem is: THEY'RE THE SAME PLANT! One has been treated in its pot to make the flowers blue, and the other has not so its flowers are pink. Once they settle down in your garden they’ll both end up the same colour – which will depend on the acidity or alkalinity of your own soil. Not surprising since they’re the same variety. That’s a bit of a con, don’t you think?

The clue is in the way the names are presented. (Flair&Flavours) Cotton Candy and (Flair&Flavours) Blueberry Cheesecake are selling names, Trade Designations as the botanists have it (which have to be presented in a different typeface). BUT both have ‘MAK20’ in brackets and this is the plant breeder’s cultivar name. I only found out about this because I contacted Crocus to say that I thought they’d got their text wrong, giving the name ‘MAK20’ to both plants. But, as they told me, they’re selling the one plant under two completely different names!

In North America the same plant is offered by Proven Winners, they call it Tuff Stuff because by American standards it’s unusually hardy. Fair enough. And they only offer it once.

But I really think Crocus need to think again. They have some excellent new plants available this autumn, and I’ll be featuring some of them over on my RHS New Plants blog; I’ve written up their new spine-free mahonia already. But not these hydrangeas – sorry, THIS hydrangea. [The fact that they're almost certainly forms of Hydrangea serrata, and not Hydrangea macrophylla, hardly comes into it...]

British gardeners can order Hydrangea macrophylla (Flair&Flavours) Cotton Candy ('MAK20') from Crocus. They can also order the same plant as  Hydrangea macrophylla (Flair&Flavours) Blueberry Cheesecake ('MAK20') from Crocus. North American gardeners can order what they call Hydrangea serrata Tuff Stuff ('MAK20') from a number of North American suppliers.

The sleepy teenager on the checkout at my local supermarket looked at the bags I’d brought with me for my groceries (above, click to enlarge). She picked up one of them and said: “What’s this made of?” “It’s burlap” says I. “What’s burlap?” she asked. Hmmm… Good question. And is it the same as hessian – which is the word we use for this rough sacking material in Britain?

This is one of those things that I must have known in my student days – well, I presume I did - but now I can’t even remember whether I never knew it all or have just forgotten. Surely it’s not made of hemp, that seems vaguely familiar…

Anyway, I had a rummage through my thousands of plant books… then I looked a bit harder and I finally came up with the answer.

First off, hessian and burlap are the same thing. Secondly, it’s made from the fibers in the skin of the jute plant (we’ll get to that) although it was once also made from hemp or sisal fibers. Hemp is cannabis sativa, while sisal is Agave sisalana – another species of which brings us tequila! So it has good connections.

Jute is derived from two species of Corchorus (right, click to enlarge), which are loosely related to mallows and hollyhocks. And it turns out that the areas of the world in which it can be grown are limited by the fact that it needs both a tropical climate and standing water. But the amount grown in India and Bangladesh is so huge that it’s second only to cotton as the world most grown fiber plant.

Combining strength with being permeable to air and moisture – says he in text book mode – hessian/burlap sacks have long been used for packing and carrying potatoes, coffee beans and other bulk agricultural crops. In North America, but rarely now in Britain, burlap is also used to wrap the rootballs of field grown trees and shrubs – hence the term B&B – balled and burlapped. In Britain container growing has largely taken over. But burlap/hessian has found a new use in re-useable shopping bags.

And the two bags in the picture? One from Terrain, the stylish American garden store, and one from Marshalls, the British vegetable seed company.  Both bags are in use every week at our local supermarket.

For bright yellow summer colour we tend think about, well… daylilies, dahlias, perennial sunflowers and rudbeckias, verbascums, echinaceas…perhaps even marigolds. But this shrub, shorter growing than many of those perennials, has brought the garden this wonderful rich yellow foliage since the spring. And come fall, it re-invents itself in rich new tones.

Hydrangea quercifolia ‘Little Honey’ (left, click to enlarge) has been growing in a well prepared, slightly acid, partially shaded bed for about six or seven years now – I said back in 2007 that I was going to move it, but somehow this failed to happen. It grew slowly at first, more quickly recently, and has reached about 4ft/1.2m across one way, 21/2ft/75cm across the other way and it’s a little over 2ft/60cm high. Very manageable.

With its slightly pink-tinged new shoot tips, it looks good in spring with blue or purple flowered woodland phlox which peep through the spring leaves. In the autumn, the plant is transformed as the foliage turns rich wine red (below, click top enlarge) before leaving us with red winter stems.

But there’s something else unusual about this plant. It was found, in 1999, as just one yellow-leaved branch on a plant of H. quercifolia ‘Pee Wee’ growing on a nursery in Washington State. But it was also found the following year, as just one yellow-leaved branch on a plant of H. quercifolia ‘Pee Wee’ growing on a British nursery.

The two plants were compared, found to be identical, and as it happens both parent plants had been propagated by tissue culture in the same American laboratory. So it was agreed that the two-yellow leaved plants could have the same name. Otherwise we would have been in a real muddle.

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.

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.

Then 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...

Even coming from England, where topiary of one sort or another is everywhere - ranging from wobbly yew pillars and neat box balls to leaping racehorses and steam trains (yes, really) – this book is an eye opener. The range of pruning artistry developed around the world is amazing.

But this is not just a book about topiary – which I suppose is usually thought of as clipping trees and shrubs into shapes. It’s also about thoughtful pruning to enhance the grace of plants without pushing them into forms which some say are simply unnatural. The elegance of conifers or wall trained fruit, for example, can be enriched by the styles of thoughtful pruning this book explains.

I have to say, I hate clipping hedges. It’s my least favorite job in the garden. But I love pruning, in fact my very first book was on pruning. And this intriguing and book is full of great ideas for both approaches.

The Art of Creative Pruning by Jake Hobson is published by Timber Press.

• The creative side of pruning and training thoughtfully explained and beautifully illustrated.
• A refreshingly international view.

            

Brits usually have a more relaxed attitude to invasive plants than Americans, partly because they’ve been studied and mapped in Britain since the 1800s and relatively few have turned out to be really nasty. Now, in three different publications, the Royal Horticultural Society (RHS) has news of one, Rhododendron ponticum, that has definitely become a problem.

In Scotland, the Forestry Commission is planning to spend £15million (almost $24 million) eradicating every single plant of R. ponticum in its forests. Now that’s what I call taking an invasive species seriously.

The RHS membership magazine The Garden recently reported that the Forestry Commission believes that about 1,630,895 acres (that’s 660,000 hectares or 2,500 square miles) are infested. The dense evergreen growth smothers less pugnacious native plants. So this is a great scheme that will not only rid the forest of what the Forestry Commission describes as “one of Scotland’s most unwelcome invasive species” but provide valuable employment in these tough times.

But how do you eradicate so very many plants, many of them large and long established shrubs, without chemicals, chainsaws or huge and heavy machinery? Well, another RHS magazine, The Plantsman, reported in June on a new technique called Lever and Mulch.

Developed by Gordon French and Donald Kennedy of Morvern Community Woodlands in Argyll in Scotland, their technique utilizes no chemicals but instead requires a pruning saw, a root saw, a hammer – and brute force – to detach the top growth from the roots. “This method is as eco-friendly as it gets, and can be done by a single fit person using gloved hands, booted feet, body weight, hammer, saw, L&M specific skills and a hearty lunch,” says the Lever and Mulch website. The stems and foliage are then left at the site as a mulch to help prevent seed germination. You can find out more on this technique at LeverandMulch.co.uk.

Finally – it turns out it’s not R. ponticum anyway! A piece in Hanburyana, the occasional journal on taxonomy and nomenclature from the RHS, reveals that the plants in Britain usually referred to as Rhododendron ponticum are, in fact, not! Recent studies have shown that in fact they belong to a rather variable and unusually vigorous group of hybrids between R. ponticum, from eastern and southern Europe, and three American species - R. catawbiense, R. macrophyllum and R. maximum. And they’ve been given a name: Rhododendron x superponticum. For more information download Naturalised Rhododendrons by James Cullen.

But whatever it’s called, it’s days in the Scottish forests are numbered.

The image of Rhododendron ponticum is used under the Creative Commons Attribution-Share Alike 3.0 Unported license. More here. The image of Lever and Mulch in use in Scotland is by Donald Kennedy. Thank you.