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July 2009

Wild lobelia

Lobelia cardinalis, cardinal flower, growing wild Off out the other day to look for what turned out to be a non-existent nursery, prior to looking in on what turned out to be the worst country auction in the history of antiques and collectibles, we turned a corner and I was startled by a dramatic scarlet flash.

We parked, got out and gawped at a drift of wild cardinal flower, Lobelia cardinalis, flowering along a small damp ditch. It was spectacular.

We have cardinal flower growing along the tiny stream that flows through one side of our property but the deer usually bite off the flower buds – they have this year. We also have Lobelia spicata, with pale blue flowers so small you can hardly see them. But that scarlet roadside forest that simply demands you stop the car made me again realise that however much I admire the creative imaginations and technical skills of the plant breeders, sometimes a simple wild flower just takes your breath away.Lobelia cardinalis, cardinal flower

And a couple of years ago I wrote up a lovely pink-flowered form, found in the wild – quite different in its appeal but equally lovely. And not yet even in bud in the garden here.

Graham Stuart Thomas in his invaluable book Perennial Garden Plants says that the cardinal flower, L. cardinalis, was introduced to Britain from the US – in 1626! That’s almost a hundred years before the east coast Aster species were taken over. Well, you can understand that returning settlers would have wanted to take such a magnificent wild flower with them.

Long life cut foliage

Heuchera 'Citronellle' and Heuchera 'Frosted Violet' Before I went over to England for the Hampton Court Palace Flower Show – on 21 June to be precise – we had some friends over for supper and I picked a bouquet from the garden which consisted entirely of foliage. Different shapes, different textures, different colors: there were all sorts of things including ferns, iris leaves, physocarpus, hostas, hellebores, vincas and lots more – including the leaves of two heucheras.

And here we are on the 27 July and those two heucheras still look great. The two varieties are ‘Citronelle’, about which I’ve bashed on here more than once before, and ‘Frosted Violet’. (The other plant peeping into the picture is Vinca minor 'Illumination' which has also lasted well.)

‘Citronelle’ is one of the new series of heucheras derived from H. villosa ‘Autumn Bride’ by the French plant breeder Thierry Delabroye. They come in all sorts of new colours but ‘Citronelle’ is the best of those I’ve grown. ‘Frosted Violet’ comes from the pioneer heuchera breeder Charles Oliver and I especially like it for its jaggedly edged foliage (so many heucheras in this colour range have rounded lobes to their leaves) and the especially smoky haze to its colouring.

Garden to Vase by Linda Beutler I took a look in last year’s splendid book on cutting flowers and foliage from the garden, Garden to Vase by Linda Beutler, to see what she had to say about heucheras. “Leaves in vase arrangements can last more then ten days,” she says. Yes, three and a half weeks longer than ten days! Actually, this is a really useful book with bucket loads of good advice and none of it too technical for those of us – almost all of us at this blog (with two very honorable exceptions I know of)  – who are not professional florists although professionals will find it valuable too.

I especially liked her recipe for home made flower preservative. I’ll give it here as an example of the good practical advice you’ll find throughout the book. It’s so simple. Use it instead of plain water.

One 12oz can of non-diet lemon-lime clear soda
Three 12oz cans of water (use the soda can as a measure)
One tablespoon of chlorine bleach

In Britain, where everything is metric, I’m sure you can work it out – just don’t use a larger proportion of bleach. You’ll need to get the book to learn about which flowers are especially sensitive to bleach.

And that’s one of my two criticisms of the book: for a book that’s sold in Britain as well as the USA, it’s simply perverse that no metric equivalents to the old Imperial measurements are given. The other problem is the fact that the author seems to have no knowledge of the research on hellebores as cut flowers published in a book from the same publisher the previous year. But if you cut flowers from your own garden, set that aside and buy the book anyway.

Buy Garden to Vase by Linda Beutler in North America from

Buy Garden to Vase by Linda Beutler in Britain from

Good and bad pruning

Trachelospermum jasminoides, star jasmine The superbly scented Trachelospermum jasminoides is sometimes known in the USA as Star Jasmine or, because it's widely planted in the South, Confederate Jasmine. It's also known as Traders Compass - oddly, since iot has five petals. Anyway... A few years ago this was a vine you rarely saw in Britain, and when you did it was usually planted on a south facing wall where it benefited from the choice position or grown in a conservatory.

But with the increase in patio gardening providing more situations which are warm and sheltered, and with the climate changing, it seems to be turning up all over the place. But this self-clinging evergreen vine needs the right pruning to ensure it doesn’t get out of hand, yet flowers prolifically.

Just opposite my daughter’s house in a south London suburb, is a lovely specimen. It’s trained on a pillar at the front gate and so that everyone who walks down the street or calls at the house can appreciate the colour and the fragrance. So they must be pruning it right.

Actually, I saw the owner pruning it once. It was a couple of years ago, in spring, and they were simply going over it briskly with the hedging shears. In much warmer climates, like Florida where it’s even used as ground cover, it’s pruned after flowering in May or June.

Lavender hedge - never pruned As it happens, a couple of houses along the street is an example of really bad pruning – or rather the bad result of a complete lack of pruning. This lavender hasn’t been pruned for years so it looks terrible. And now it’s too late. The thing is: lavender usually refuses to grow if you get out the saw or the long-handled pruners and cut into old thick wood. Do that with this hedge and it will probably die.

Better to tear it all out, improve the soil and put in some new plants – which should be pruned after every flush of flowers, snipping back to just above the old wood.

Japanese knotweed madness

Japanese knotweed, Fallopia japonica Over on Jane Perrone’s gardening blog for Britain’s Guardian newspaper, there’s news of a new initiative to control Japanese knotweed, Fallopia japonica. British government ministers are seeking people’s views on a proposal to release the non-native insect, Aphalara itadori, to help control it. The insect is a  psyllid (jumping plant louse) that feeds on the sap of Japanese knotweed, weakening the plant and making it easier to kill.

OK… Where shall we start?

1. This follows the highly suspect rationale of introducing one non-native species to control another – not an idea crowned with undaunted success.
2. It doesn’t control Japanese knotweed anyway, the British government says the insect will only “attack the plant to reduce its vigor, thus reducing the use of chemicals and the costs of control including weedkillers and physical removal”.
3. Jane quotes scientists as saying: “it's unlikely to start attacking other plants that we'd rather not see decimated, or to affect native fauna.”. Hello! An attractive garden perennial from Japan is unlikely to start emerging through the middle of concrete paths.
4. The government also says: “The findings suggest that only a few closely-related non-native knotweeds are potential hosts in Britain.’ Garden plants, perhaps? At least it will attack those ghastly variegated Japanese knotweeds some nurseries sell!

You have three months to object to this, start here.

In the meantime, enjoy this great video that Jane found on YouTube.

New plants at the largest flower show in the world

Allium 'Dready'. Image: © My list of all the new plants I spotted earlier this month at Briatin's Hampton Court Palace Flower Show, the largest flower show in the world, is now online on my Royal Horticultural Society New Plants blog. Almost a hundred new introductions are listed - including this weird new allium for cut flower use, 'Dready' -  with links to the individual blog posts in which I wrote them up. Almost all are available from British nurseries, many are available from North American nurseries

Back from New Plants Nirvana

Absolutely Fabulous ('Wekvossutono') - 2010 Rose of the Year launched at the 2009 Hampton Court Palace Flower Show. Image: ©RHS Forgive me, readers, for I have sinned. It’s been nineteen days since my last post.

How time flies when you’re blogging furiously elsewhere. I’m just back from England where I was writing up all the new plants at the largest flower show in the world – the Hampton Court Palace Flower Show - for my Royal Horticultural Society New Plants blog. I haven't yet counted up all the new plants I discovered - it must be nearly a hundred and there were some stunners - but I ran fifty posts in three weeks. Begin here and work back to the starting point on 1 July. I’ll be posting a full list of all the plants I discovered here at Transatlantic Plantsman as soon as I can get it together and add in all the links.

Lots of new perennials including eleven heucheras and related plants from the USA and some intriguing new roses. The Julia Child ('Wekvossutono') rose (above) was launched in Britain for the first time under the name Absolutely Fabulous ('Wekvossutono'). And it’s because roses (more than most plants) have their marketing names changed for the different countries in which they’re sold – no one in Britain has even heard of Julia Child – that we need that cultivar name in brackets carried with the marketing name so we all know they’re the same rose.

Gladiolus tristis hybrid - New at the 2009 Hampton Court Palace Flower Show. Image: © Amongst the other plants I especially liked were a new, as yet unnamed three way hybrid Gladiolus; some extraordinary “hairy” alliums for cut flower; a lovely dwarf fragrant Phalaenopsis hybrid; and a new pink trailing Campanula.

Normal service is now resuming here – and I’ll be posting that full list soon. In the meantime, check out the full list of new plants I found at the Chelsea Flower Show.

Britain's Favourite Perennial varieties

A few days ago I discussed Britain’s Favourite Perennials, the best selling individual genera as evidenced by sales at the Royal Horticultural Society’s Plant Centre at Wisley in Surrey. And I compared the current list with the Top Ten from three years ago. Today, let’s do the same for individual varieties.

So this is the current Top Ten of individual perennials sold at the Wisley Plant Centre. There are far more comings and goings in the last three years than there were with individual genera:

10 Lithodora diffusa ‘Heavenly Blue' – Up quite a few places from three years ago, it’s been around for ever.
9 Geranium Rozanne (‘Gerwat’) – Number six three years ago, this superb plant for ground cover or containers has been overtaken by both new and old favourites.
Primula vialii. Image: © KENPEUI used here under the GNU Free Documentation License 8 Primula vialii – The triumph of hope over experience! So enticing in flower in the plant centre but difficult to keep going from year to year so people just go back and buy it again.
7 Heuchera ‘Peach Flambé’ - A new colour in heucheras, these vibrant colours are supplanting those in darker shades.
6 Scabiosa ‘Pink Mist’ – Increased interest in attracting butterflies has surely helped this pretty plant enter the Top Ten.
5 Verbena bonariensis – Amazingly topped the chart three years ago, now slipped but still essential to so many gardeners. A white form would take the country by storm. Anyone ever seen one?
4 Erysimum ‘Bowles Mauve’ – Slipped from number three, but its very long flower season and good foliage still create demand. Technically a shrub but so often, strangely, classified as a perennial.
3 Gaura lindheimeri Cherry Brandy (‘Gauchebra’) – Like a much improved version of the old favourite ‘Siskiyou Pink’. Three years ago there were three gauras in the top twenty, now there’s just this one in the top twenty five.Heuchera 'Georgia Peach'. Image: ©
2 Heuchera ‘Georgia Peach’ – Unique colouring, looks great in a pot on the sales bench and in a pot on the patio.
Scabiosa columbaria 'Butterfly Blue'. Image: ©Walters Gardens, Inc 1 Scabiosa ‘Butterfly Blue’ – introduced as long ago as 1985, missing from the Top Ten (and the Top Twenty) three years ago – and now back on top. In 2000, 'Butterfly Blue' was also voted Perennial Plant of the Year in the United States.

On the other hand, dropped out of the Top Ten over the last three years are:
Imperata cylindrica ‘Rubra’, formerly Number Two, which has now vanished from the top twenty five;
Primula vulgaris, the British native primrose, formerly number four but still in the top twenty;
Erigeron karvinskianus, number five three years ago and not now even in the top twenty five;
Helleborus Ashwood Garden Hybrids has also vanished from the top twenty five;
Delphinium ‘Blue Butterfly’, also gone from the top twenty five;
Heuchera ‘Plum Puddin’’, also gone from the top twenty five;
Gaura lindheimeri has also gone from the top twenty five, but been replaced by a cultivar.

Thank you again to Malcolm Berry, Head of Buying at the RHS Plant Centres at Wisley in Surrey, Rosemoor in Devon, Harlow Carr in Yorkshire and Hyde Hall in Essex, for getting these fascinating figures together for me.