Transatlantic Gardener is back!



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It’s been quiet around here recently, hasn’t it. Sorry about that: lyme disease, new grandchild, selling an apartment, buying a house, renovating a house… Lots of stuff going on. Not enough hours (or energy) in the day.

But here we are again, and we’re appreciating the perennial advice that when we move into a new home we should take a year assessing the garden before we make any changes. One of the few old garden maxims that actually makes sense.

We looked over our new English cottage (above), just round the corner from the previous one, two or three times in the spring and summer before buying it and noticed the mature specimen of the yellow-leaved form of the pheasant berry, Leycesteria formosa Golden Lanterns (‘Notbrue’) (below), with its supposedly golden leaves and purple late summer and autumn flowers. Have to MalusGoldenHornet_GJR0025-700say… the leaves look a little more bleached than gold. But I don't think it will be for the chop, I know its color will be better in spring: unlike the hideous pink and white variegated willow (Salix integra ‘Hakuro Nishiki’) which I just can't bear to illustrate – where's the saw?

Back in the summer, we had no idea that we had pink and white hardy cyclamen because they were dormant. Now, they’re  lovely. Nor that the huge upright holly in the neighboring garden would prove to be a ‘Camelliifolia’, now heavily laden with scarlet berries. Or that there was a ‘Golden Hornet’ crab apple (above) on the other side also dripping in fruit: there should be plenty of birds enjoying the bounty.

And it turns out that we also have two large and mature (so far unidentified) viburnums, also developing berries. And I know there are snowdrops because some irritating creature had dug them up and scattered them about. The feeders are up, and the birds quickly found them. And the red kites continue to keep an eye on it all from overhead.

Anyway, I'm very pleased to say that postings from the Transatlantic Gardener have resumed. Thank you for your patience – and for checking in today. There'll be a little flurry of catch-ups before things settle down again.

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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.


Roadside surprises

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Driving around Pennsylvania or Northamptonshire, while keeping my eyes on the road, my peripheral vision always takes in what’s growing by the roadside. And there’s plenty to see.

One of the very first posts on this blog, way back in 2007, was about unexpected roadside plants and here we are almost ten years later and over the last few days I’ve spotted some more.

First, let’s revisit the Heathrow euphorbias (above). Having driven round the exit from London’s orbital motorway, the M25, for Heathrow every few months for more than fifteen years – about four years ago I spotted Mediterranean euphorbias bursting through the barrier. Driving my wife judy to the airport last week she snapped this picture on her phone through the car window as we whizzed by. Those euphorbias are still going strong.
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Later, on the way home to Northamptonshire, I spotted something interesting as I turned off the northbound M1 motorway to head home. And it turned out to be a strange mixture of plants: stinking hellebore (Helleborus foetidus) (below) scattered by the side of the road along with Euphorbia amygdaloides var. robbiae, grape hyacinths (Muscari), jonquil daffodils, flowering currant (Ribes sanguineum) and more: a strange mix of garden plants at an exit that’s a long way from a garden.

And then just yesterday, on the way back from the recycling centre, doing very nicely by the roadside – two or three patches of another Mediterranean plant: Alexanders (Smyrnium olustratum) (above right). The Flora of Northamptonshire tells me that it: “originates from it formerly being grown as a medicinal herb”.

Now that our roadsides are not treated like lawns and mown every two or three weeks, there’s more and more interesting plants to see.

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Graham’s Transatlantic Guide to Weeding

CalystegiaSepium700I’ve been doing some weeding. This is in our British garden where the weeds are always jumping at this time of year, especially when it’s been so wet and it’s been unwise to get on the soil.

I’ve also been having a clear out, bringing files and folders out from the back of the file cabinets and what did I find? My weed collection, three fat folders of pressed plants, that I made when I was a student at the Royal Botanic Gardens at Kew in London almost forty years ago (below right, click to enlarge).

And the first pressed plant I found in the first folder I opened was the same plant I’d just been pulling out of the garden: hairy bitter cress (Cardamine hirsuta). We have a close relative, Pennsylvania bitter cress (Cardamine pennsylvanica) in our American garden.

And this brings me to my first rule of weeding: our top weeding priority should always be to pull out are the weeds that are in flower or developing seeds. Hairy bitter cress rarely grows more then 10in/25cm high but can still can produce 700 seeds and fling them 31in/80cm, but it can also produce seeds when just two inches (5cm) high. So pull it out. Now.

Many of the traditional rules of gardening have little value but “One year’s seeding makes ten years weeding” really is true. Dandelions (below), which as annoying in Pennsylvania as they are in Northamptonshire, can produce over two hundred seeds in one seed head. So - obviously - don’t let them seed.

My second rule of weeding is always to shake the soil off the roots after you pull out the weeds and before they go on the CardaminePressedcompost heap or (in those cities with green waste recycling) in the green waste bin. You can ship out a huge amount of good soil if you’re not careful.

And my third rule of weeding is this: get them when they’re young. When nasty perennial weeds like bindweed come through at this time of year, a one inch shoot is often an indicator of yards of root underneath. Later, when their twirling stems become entwined with our garden plants, it’s all but impossible to remove them. It’s so much easier when they’re just an inch high and, at this time of year, if you disturb the plants you’re trying to protect when extracting bindweed roots they’ll soon settle down again. By the time the bindweed is strangling your cistus (top) it’s far far FAR too late.

My final rule is this: Don't spend half a day weeding and then the rest of the week nursing your aching back. I did half an hour this morning and half an hour this afternoon and I’ll try to keep that up. But if I’d spent two hours forking out weeds at a single stretch this morning (as I was tempted to do) I’d not be able to get out there again tomorrow or the next day or the rest of the week. Little and often…

OK, it's time to get back to the bindweed and dandelions and the dreaded hairy bitter cress.

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A shortage of flowers and gardens at the San Francisco Flower & Garden Show

Guest post by lawyer (and nephew)  Jonathan Weisbrod

The water gardens caught the eyeI distinctly remember the first Flower & Garden Expo I attended. In the mid-90s, my family went to the Philadelphia Flower & Garden Show. It was a rather grand experience, between floral displays and booths upon booths of plants I had never heard of or seen before. Admittedly grandeur to someone under the age of ten is easy to come by.

Over the years since I’ve attended a lot of festivals and conventions celebrating everything from hot air ballooning to chili peppers, but beyond “craft & garden” fairs – nothing with horticulture at the forefront. As a recent transplant from New Jersey to San Francisco, it seemed appropriate to try and take in my new coast. Why not spend a day at the San Francisco Flower & Garden Show? #throwbackthursday or in this case Saturday.

To be fair, I knew my past expectations needed to be tempered, still I was surprised by the amount of craft fair wares available relative to the garden vendors (how many people do you need selling aged balsamic vinegar?). The event felt more like a crafts fair with gardens added on than a garden expo colored by craft vendors. The proliferation of gutter cleaning devices, new windows, and college-student MLM king Cutco takes a bit away from the whimsy.

Oh right, the garden displays. There were some very pleasant, zen displays. However, More gardens and flowers would have complimented the non-horticultural displaysthey weren’t just an afterthought in this reflection on the show, they felt like one at the show itself. The actual garden displays numbered just over half a dozen but with rather narrow scope. As such a novice, perhaps it's not surprising the water displays jumped out at me most – but they certainly felt more the focus of each set up rather than anything floral (though a raining bridge is cool concept for a few minutes).

All-in-all mixed feelings, not an overwhelming disappointment, but far from a success in my book. I was able to learn a bit about products to implement in my own garden which certainly a big plus, if only I gleaned more about plants to put in it…


Sycamore? Or sycamore?

American sycamore, Platanus occidentalis, growing on the New York side of the Delaware River. ©GardenPhotos.com

Gardeners and botanists both use common names as well as scientific names when referring to plants. Using common names for plants is more widespread in North America than it is in Britain, even among botanists, and even though common names are often simply made up if there doesn’t seem to be one already in use. But common names are confusing. After all, there are more than twenty different plants, from around the world, that are called “bluebells”.

Native Americans must have had local names for many native plants when settlers first arrived in North America but the settlers didn’t bother to learn them and simply made up new ones - or, as with birds like the robin, transferred a familiar common name to a plant that looked vaguely similar to one from back home.

So when I saw a large mature sycamore (above) way across the Delaware River the other day, its white branches ghosting against the oaks and maples behind, I was reminded of this: in Europe, sycamore is used for Acer pseudoplatanus; here in North America sycamore is Platanus occidentalis. The leaves are very similar, so I presume settlers simply transferred the name. But surely, native Americans must have had a common name for P. occidentalis. After all, I’m told they used to tap it for sap in the same way as sugar maples.

In Europe, P. occidentalis is the plane tree and its hybrid with P. orientalis is a familiar city street tree. In Paris, large plane trees in the streets are pruned – literally – into a plane with all the branches parallel to the street and none overhanging.

The sycamore of Europe, Acer pseudoplatanus (below) - whose botanical name, by the way, literally translates as “the maple that looks like a plane tree”! - is a menace. There’s a huge one in our neighbor’s garden in England and its seedlings spring up all over the place. What’s worse is that they get their new roots down deep quickly so that even when they’re less than a foot high they can be tough to extract, especially between the cracks in paving.

I’d much rather have the American version.

European sysamore, Acer pseudoplatanus, growing at Parc de Mariemont in Belgium © Jean-Pol Grandmont. Licensed under the Creative Commons Attribution-Share Alike 3.0 Unported license.
Acer speudoplatanus image (above)  © Jean-Pol Grandmont. Licensed under the Creative Commons Attribution-Share Alike 3.0 Unported license.


Australian pelargonium found wild in Britain

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One of the most interesting features in the BSBI News, the magazine for members of the Botanical Society of Britain and Ireland, is the section headed Adventives & Alien News. This is where news of the more interesting non-native arrivals is posted.

In the current issue there’s news of two related plants very rarely seen in Britain, one so unexpected that it gets a short article all to itself.

The most surprising news is that Pelargonium inodorum (above), a native of Australia and New Zealand, and not grown in British gardens, has been found growing on the Isle of Wight - off the south coast of England. Spotted last September, it was happily flowering away on a sandy bank near a boating lake in the town of Ryde, across the road from the beach. It seems to have been there for a few years as there are large and small plants.

Interestingly, it is also said to have become established in California, but the California Native Plant Society has no records. So often, when a non-native plant turns up in the wild in America, the reaction is to discuss how to eliminate it. The Botanical Society of Britain and Ireland publishes records and monitors the continuing status of new arrivals so that any such decisions can have a scientific basis.

ErodiumTrifolium700As it happens, there’s news of a related plant that has also started turning up on the Isle of Wight. A heron’s bill that’s native to North Africa, Erodium trifolium (left), was first spotted near Dartford in Kent in 1999, but has now been found in two different places on the Isle of Wight. A large plant was found on an industrial estate and half a dozen plants on a mown roadside verge. That original find in Kent was described as “an extensive weed on walls and roadsides”.

This is a very attractive species which is grown in gardens and listed in the latest RHS Plant Finder as stocked by five nurseries, none of which are on the Isle of Wight.

Other interesting sightings mentioned in this latest BSBI News include:
* Portulaca oleracea, the kitchen garden purslane, native to India, established in two sites in different parts of Sussex;
* the drought tolerant Gaillardia x grandiflora naturalised on sand dunes in Kent and increasingly popular in gardens;
* purple-flowered Verbascum phoenicium, found in Staffordshire in the English midlands.

The point of all this is that recording these plants, and following their status over time, is the basic science from which conclusions can be drawn about their spread – or their disappearance. Indigofera hirsuta is considered invasive in parts of North America, but a plant of the closely related Indigofera heterantha found in Sussex in 2012 has since gone. We need to know when species do not spread as well as when they do. Ripping them out as soon as we see them tells us nothing.

Thank you to Peter Heenan of Landcare Research for permission to use his image of Pelargonium inodorum. The image of Erodium trifolium is licensed under the Creative Commons Attribution-Share Alike 3.0 Unported license. Details here.


The day our echinaceas died

Echinacea 'Flame Thrower' © Terra Nova Nurseries
The day the echinaceas died... It was yesterday. And this is how it happened.

Echinaceas, coneflowers, and especially all the fancy hybrids that have come on the market recently, like ‘Flame Thrower’ (above) and all the doubles (below), hate bad drainage in winter. That’s what kills them. But yesterday that’s exactly what they got.

On Sunday night the temperature in our garden here in Pennsylvania went down to -10F (-23C). So, after a temperature almost as low the night before, and low temperatures for a few days before that, the ground was frozen solid to a depth it was hard to assess.

And then it snowed. Not a lot, just a couple of inches and the whole garden looked lovely. But then, yesterday, Monday, it got warmer. A whole lot warmer, and quickly. By early afternoon the temperature had risen to 48F (9C), and the snow had melted and the top inch or two of soil had thawed out as well.

But because the soil was frozen down deep, all the melted snow just sat there on the surface, in puddles – it could not drain away because the soil underneath it was frozen. Our borders were covered in pools of water, yesterday, and they’re still there this morning.

And in those puddles of thawed snow are the crowns of our last remaining echinaceas (this has happened before...) – and echinaceas hate bad drainage. So those last few may well die.

Of course, this is not a phenomenon that comes into play in Britain all that much, or in parts of the USA where the winters bring less ferocious frosts. Because if the soil is not so solidly frozen, melted snow drains away and impacts much less on our, rather sensitive, echinaceas.

But here's what's important: it reminds us that, wherever we garden, it’s bad drainage in winter that prevents us enjoying the vast range of exciting new echinaceas for years and years after we first planted them. Which is a shame, because they really are gorgeous. As you can see.

Double echinaceas from Marco van Noort. ©Luc Klinkhamer


Sparkling new dwarf spring irises

Iris 'Eye Catcher'. Image © Alan Mcmurtrie
Reticulata irises are one of the joys of spring, but we seem to have been growing the same varieties for decades. In fact, the ones I used to look after when I worked in the Alpine House at Kew Gardens over thirty years ago are, basically, the ones we still grow. Well, until now.

There’s a fascinating piece in the Royal Horticultural Society’s monthly membership The Garden this month, by Assistant Editor Phil Clayton, about Canadian iris breeder Alan McMurtrie and the amazing varieties he’s developed.

Iris 'Storm'. Image © Alan McmurtrieIt’s been a long haul. Alan began his work many years ago, soon after I was working with the irises at Kew, in fact, but it takes five years for the seed produced by crossing one variety with another to build a big enough bulb to flower. And that’s only the start, because after two or three generations of crosses and selections and a new seedling is finally seen to be good enough to be named – then a large number of bulbs have to propagated so that they can be sold and that takes a long time. Alan has been developing these lovely little plants for thirty years and only now are his new varieties becoming available to gardeners.

He’s been continually expanding the range of colors and color combinations. The white ‘White Caucasus’ and the blue-and-white ‘Eye Catcher’ (top) were amongst the first to be named but Alan also has improved varieties in the familiar blue and purple shades, 'Splish Splash' (below), along with new varieties in vivid yellow, and orange, yellow with navy blue marks and with smokey tints ('Storm', left) or brown speckles…  They’re just amazing.

You can read the article about Alan’s irises from The Garden online, and in next month’s issue of another Royal Horticultural Society magazine, The Plantsman, you can read a more detailed account. Alan McMurtie is refreshingly open about his work and Alan's website includes many pages of details and a huge number of pictures.

Alan is lecturing in Britain this month, so this is a great opportunity to hear about his irises from the man himself. He’ll be speaking at the RHS London Flower Show on 16 February, at a meeting of the Scottish Rock Garden Club in Dunblane on 20 February, and at the Alpine Garden Society’s show at Harlow in Essex, just north of London, on 27 February. At present, he has no North American lectures scheduled.

Iris 'Splish Splash'. Image © Alan McmurtrieLike to buy some bulbs? In Britain take a look at the offerings from Jacques Amand, at Broadleigh Gardens, at Pottertons, and at Rare Plants. In North America you can buy some of Alan’s varieties at McClure & Zimmerman, at White Flower Farm and at Botanus.com. Of course the plants are flowering now, you ill be able to order bulbs later in the year.

Jacques Amand featured Alan’s irises at the Philadelphia Flower Show last year, and will do so again next year, but this year the theme is tulips. This week’s RHS London Flower Show will feature an extensive range, shown by Jacques Amand

Oh, yes… You want to know how to grow them. Here’s what Alan recommends:

“They should be planted 3in (8 cm) deep in well drained soil (a touch deeper is fine). They don't mind snow melt in the spring, but don't like to be near a downpipe in summer. Plant about the same distance apart. Resist the urge to plant too close together. If you've given them the right conditions they will form clumps.

“Remember new bulbs are forming at the base of each leaf. They represent next year's bloom. So don't go ripping them out and wonder why you don't have flowers next year. The longer they stay green, the bigger the bulbs will be.”

Images  © Alan McMurtie Thank you for making details of your work so freely available.


Most Christmas roses used to be pink!

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“The Christmas Roses with which one meets in the majority of gardens are not white, but pink, or more or less suffused with pink or dirty purple.”

Really? Well, perhaps it was true in 1878 when a certain Mr. D. T. Fish wrote those words in William Robinson’s epic journal, The Garden, although it seems unlikely. He then goes on to explain in detail how to make Christmas roses (Helleborus niger) white.

Even allowing for the artist’s overenthusiasm, this Giant Christmas Rose, illustrated in The Garden in 1878 (above), is impressive and well illustrates how the coloring works: individual flowers open white and develop pink tones and become richer in color as HelleborusLouisCobbett700they mature. Sunset Group, collected in Slovenia by veteran British hellebore expert Will McLewin was similar (but a whole lot less dramatic). Dark stemmed ‘Louise Cobbett’ opens with pink backs to its flowers and later develops additional pink tints but it’s not the color of the Giant Christmas Rose.

Neither is Blackthorn Group (below), developed by acclaimed hellebore and daphne breeder Robin White from ‘Louise Cobbett’ (right) and ‘White Magic’ although it’s a lovely thing.

Strangely, Josef Heuger, in Germany, who has introduced so many fine forms of the Christmas rose recently - ‘Jacob’ flowers dependably in November here in Pennsylvania - has created no pinks. Most of the pink ones such as ‘Pink Frost’ which listed as H. niger by mail order nurseries are actually hybrids. If Ernie and Marietta O’Byrne of Northwest Garden Nursery in Oregon, who’ve created so many spectacular double and single forms of H. x hybridus, turned their attention to Christmas roses we’d be in for a treat.

Anyway, it’s interesting (if difficult to believe) that pink was once normal in Christmas roses and that detailed suggestions were given in The Garden for turning them white.  And what, in short, were the recommendations: “light soil”, “a warm, sheltered, partly-shaded situation” and “cover them with glass”. Somehow that doesn’t really seem a very convincing way to change their color…

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