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November 2011

Book Bullet: The Cottage Garden

CottageGardenJacketHistoric paintings and a lively text make this little book a really good introduction to the development of cottage gardens in Britain. Paintings by artists like Helen Allingham, which are not over idealised, give us a sense of how nineteenth and early twentieth century cottage gardens really looked.

Twigs Way explains the origins of the cottage garden in its value as source of both food and flowers and considers its place in the moral landscape of Victorian England as well as the everyday lives of the people who made them. She then brings us to date with glimpses of how cottage garden style influences the design of today’s gardens.

  • Historic paintings give a contemporary idea of Victorian cottage garden style
  • Lively overview of cottage garden development

The Cottage Garden by Twigs Way is published by Shire Publications



Invasives in Britain: a balanced view

Himalayan balsam: 'largely only displaces other aliens or thuggish natives,' says David Pearman. Image used under the Creative Commons Attribution-Share Alike 3.0 Unported license.There’s a lot of nonsense talked about invasives so it’s refreshing to see one of Britain’s most respected botanists talking some real sense. David Pearman is a former President of the Botanical Society of the British Isles and a leading light in the development and publication of one of the most vital British plant publications of our times, the New Atlas of the British and Irish Flora.

In a piece entitled The Alien Invasion Myth which appears in the current issue of The Garden, the membership magazine of the Royal Horticultural Society, he writes: “For the last 20 years I have coordinated our Society’s largest network of botanical recorders (from the Botanical Society of the British Isles): together we have accumulated about 18 million records, covering the entire area and 4,000 species. In simple terms, the data shows that most aliens are rare; that they occur overwhelmingly in and around towns and transport networks; and they are generally uncommon in the semi-natural habitats that we most want to preserve. Recording alien plants is, broadly, a recent phenomenon, and all extrapolations are to be taken with a pinch of salt.”

He goes on: “But the real, inescapable line is that our countryside and flora is changing like never before, mainly from abandonment of traditional management practices and pollution. It is largely ‘native’ plants that are to blame – look at the chalk downlands of southern England (choked with gorse on the dip slopes) or our rivers (a vast increase in reeds, due to higher nutrients).” 'Native Bluebells, Hyacinthoides non-scripta, are under only a minute and local threat from garden outcasts,' says David Pearman. Image © (all rights reserved)

Of course the situation is slightly different in North America where there’s more genuinely natural habitat; in Britain almost all habitats are, as he puts it, “semi-natural” – most woodlands, meadows, mountains and aquatic habitats show the hand of man in some form. But in North America there’s also a tendency to rip out any non-native plant that turns up before anyone has had the chance to record its distribution or study its tendency to spread – or, perhaps, its tendency simply to fade away.

Changes in management, and pollution, are the drivers of change in Britain’s natural habitats, says David Pearman. We can hardly blame plants for what happens as a result.


Himalayan balsam image by ArtMechanic used under the Creative Commons Attribution-Share Alike 3.0 Unported license. Thank you.

Book Bullet: Crocuses - A Complete Guide

CrocusesThis imperious volume is an exhaustive and profusely illustrated account of Crocus species in the wild and in gardens. Based on the author’s own studies of crocuses in the wild, and his experiences growing them in his Latvian garden, it’s the wild species – about a hundred of them - which take precedence.

The detail given over both to the place of these species in their natural habitat and to how to grow them well is rich and fascinating and the three hundred pictures are invaluable. But, like the recent book on Phlox from the same publisher, with the focus on wild species many popular cultivars receive minimal treatment.

Nevertheless, this is an extraordinary book and testament to the enthusiasm and insight of a great plantsman.

  • Comprehensive overview of Crocus species and how to grow them
  • Three hundred excellent colour pictures

Crocuses: A Complete Guide to The Genus by Janis Ruksans is published by Timber Press.


Wipe Out! Getting tough with invasive rhododendrons

Rhododendron ponticum - invasive in Scotland
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.

Debris from the Lever and Mulch technique for removing Rhododendron ponticum.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

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.

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.


Organic broccoli: is it really better for you?

Broccoli Marathon - more antioxidants when organically grown? Image ©Marshalls SeedsMany of us feel that organically grown food is better for us then food grown by what have become conventional methods but rarely is it actually proved that organically grown food is more nutritious. Perhaps, says he, because it isn’t more nutritious – it's just that it doesn’t have the chemicals.

But the other day I noticed a small piece in the ResearchMatters column of the British trade magazine Horticulture Week (login required) which summarizes research published in the latest issue of The Journal of Horticultural Science & Biotechnology. And this research finds that organically grown broccoli has higher levels of antioxidants than conventionally grown broccoli.

The variety ‘Marathon’ (above, click to enlarge), popular with both home gardeners and commercial growers, was grown on the same site by both conventional and organic methods. Florets were tested for a range of factors, and organically grown and conventionally grown broccoli showed no difference – except in antioxidant content.

I don’t subscribe to The Journal of Horticultural Science & Biotechnology, perhaps I should, so I’m not able to study the research paper in full but the publically available abstract looks promising. And study reported in Britain’s Guardian newspaper four years ago also shows the promise of organic culture as does a paper on blueberries in The Journal of Agricultural and Food Chemistry.

Of course, I'm not an organic chemist, So I popped downstairs and asked judy, who holds double-major B.S. degree from Rutgers University's College of Agriculture and Environmental Science. She told me: “There is a lot of controversy in the scientific world about how bad most of the studies have been. The broccoli one is not statistically significant. Also, the word “antioxidant” is not even used the same way by different studies; various compounds are given a number of different names and it's not regularized.”

Hmmm… So we have to be a little careful and not get carried away. But whatever proves to be true about the nutritional content, at least we know organically grown food has not been sprayed with chemicals.

Just one other thing… Many years ago, the British organic gardening charity Garden Organic (known back Potato 'Desiree' - more Vitamin C than other varieties. Image ©Marshalls Seedsthen as the Henry Doubleday Research Association) did some studies on the nutritional content of different varieties of potatoes, I think it was, and carrots. They found that varieties varied enormously in their vitamin content.

And I just come across a study from Slovakia which showed that the popular potato variety ‘Desiree’ (right, click to enlarge) can have more than twice the Vitamin C content of other potato varieties.

So the variety you choose to grow may well turn out to be more important, from a nutritional point of view, than anything else.

BTW British gardeners can buy both the varieties mentioned from Marshalls Seeds. In North America Broccoli 'Marathon' is available from Harris Seeds, and potato 'Desiree' is available from Seed Savers Exchange.

Rock in your (expensive) bird seed?

Sunflowers grown for their seed. Image © (all rights reserved)
Last winter I posted about the cost of sunflower seed, the black oil sunflower seed that is such a favorite with so many of our garden birds. In our friendly local Farm Plus farm supply store a 40lb bag cost $18.96 (47 cents per pound). Later, in the summer, they gave up selling it – they were so outraged by a huge price hike that they refused to stock it. So we bought the less oil-rich striped seed instead.

Yesterday, in a bird seed supply emergency (OK, bad planning), I ran out to our nearby small independent pet store for seed – their black oil sunflower seed cost $58.29 for a 50lb bag ($1.17 per pound). More than twice the price of less than a year ago!

But there’s another interesting point. Some time during the summer I picked up a bag of black oil sunflower seed somewhere else. I can’t remember what it cost, in this case that’s not the point – it was the ingredients. You’d think a bag of black oil sunflower seed would contain, well, black oil sunflower seed. Not so fast: Pennington Classic Black Oil Sunflower Seed contains: Sunflower Seed, Vitamin A supplement, Vitamin D-3 Supplement, Potassium iodide and Vegetable Oil.

Battling for bird seed. Image © (all rights reserved)Here’s my question: What’s the point of adding vitamins? These added vitamins only be on the outside of the seed coat, the part most birds drop on the ground! What’s more, the Pennington website says their black oil sunflower seed is “fruit flavored?! This is not bird care, it’s marketing.

But then I find, over on the Cole's Wild Bird Products webpage headed Bird Seed Myths, they make it very clear that wild birds don’t need supplements. They also reveal how, exactly, these supplements are added:
“…the most common way for companies to add “vitamins” to their products is to simply coat it with mineral oil and add crushed rock. (They add rock!!!) Current regulations allow a manufacturer to list the nutritional components of mineral oil (iron, zinc) and crushed rock (Vitamin A, calcium carbonate) separately, which can make the birdseed ingredients look more impressive than they really are… and of course the crushed rock adds weight to the final product.”

Amazing isn’t it. Crushed rock…

Now I’ve no idea if the good people at Pennington add rock to their sunflower seed or not but I suppose the answer to all these issues is to grow your own. Perhaps we would if we had a big sunny patch in which to grow it. But it’s pointless growing sunflowers under our trees; they’re called sunflowers for a reason, after all.

Lesson in witch hazels

HamamelisMollisPlusRootstockI’m sure that at about this time of year, you’ve come to expect an enthusiastic post about American native witch hazel. There was one back in 2007, and also one in 2009. There’ve been more. Well this year – not quite. American native witch hazel – yes. But with a twist.

The picture shows our rapidly growing Hamamelis x intermedia ‘Pallida’; its has large, bright yellow spidery spring flowers. Here, on its spreading branches, you see its fall color on the wane and turning biscuit brown before it finally drops off. But, in the middle, on a very vigorous and absolutely vertical shoot which is only a couple of years old, are some bright yellow leaves.

That bright yellow foliage does not belong to H. x intermedia ‘Pallida’. It’s foliage on growth which has shot up from the rootstock on to which is ‘Pallida’ is grafted. A scattering of small flowers opened not so long ago to confirm that the vertical growth is a shoot of H. virginiana - the American native witch hazel, H. virginiana - on to which varieties of the spring flowering Asian witch hazels are grafted.

So not only is this ‘Pallida’ an impostor without its trade mark strong scent, as I remarked last year, but its rootstock is threatening a takeover.

Where are those pruners?

Ivy reveals how nature is nuanced

Ivy growing on a stone wall. Image © (all rights reserved)In North America, in spite of uncertainty about exactly which species is involved, ivy is widely condemned as an invasive plant that smothers natural vegetation. And it’s true, whether it’s Hedera helix or H. hibernica that’s causing the problem, ivy can be a menace in some areas although in much of the country it doesn’t grow at all and in other areas it remains well behaved.

But seeing this ivy on the wall of an English stone cottage (left, click to enlarge) reminded me that ivy can cause other problems even in Britain where it’s a valuable native plant popular with insects and birds and a widely popular ornamental climber for walls.

It has clearly once covered this limestone wall but has been cut off at the root and most of the growth removed. But it’s still growing, rooting into the mortar and renewing its hold. Looks like a job for Round Up, now, because the mortar traditionally used between the stones is relatively soft; when it’s pulled off, the mortar tends to come away too. Click he picture to enlarge it and you can see.

On modern walls built of hard bricks and hard mortar, a completely opposite problem can arise. In the picture below (click to enlarge), the bricks and mortar are so hard that the short aerial roots with which ivy stems grip their support have failed to take hold well. The weight of a rainstorm has pulled the ivy right off the wall.

These situations serve to remind us, on both sides of the Atlantic, that enthusiasm for a plant, and condemnation of it, are not simple black-and-white issues. Nature is nuanced, rarely is a simplistic view justified.
Ivy falling off a brick wall. Image © (all rights reserved)

American chrysanths in England

Taking a look at the Royal Horticultural Society’s trial of hardy chrysanthemums a week or two back, I was pleased to see some recently developed American varieties included. And they’re very different from the old Korean chrysanths, also American, but developed almost eighty years ago.

Korean chrysanths, including ‘Sheffield’, ‘Venus’ and ‘Mary Stoker’, and others like them, tend to be medium height upright plants with all the flowers towards the top. Sort of traditional looking. They were originally developed in Connecticut from the 1930s, where it’s colder than in Britain, so in Britain and much of the US they’ll survive the winter.

Varieties in the Mammoth Series, developed by the University of Minnesota, are entirely different. They develop into low rounded domes and at their peak (top, click to enlarge) are covered with flowers. “Plants are hemispherical in shape with flowers almost completely covering the outside surfaces of each plant, like a pincushion. Previous mums, like most other flowers, bloomed only at the top of long stems. Shortly thereafter (after their first introduction), all U.S. breeding programs were producing garden chrysanthemums with this plant habit. The cushion is now the primary plant phenotype in the market.” So says a scientific paper on the plants in HortScience.

Plants in the Mammoth Series are hardy too, hardier than Koreans; they’ll take -35F (that’s -37C)! That’s a lot of frost.

‘Mammoth Coral Daisy’ (top, click to enlarge) makes a plant about 3ft/90cm wide and 20in/50cm high – andChrysanthemumMammothLavenderDaisy covered in coral red flowers with yellow eyes. But, while this is an impressive looking plant, nearby is ‘Mammoth Lavender Daisy’ (right, enlargement not necessary) which is long gone.

OK, that may not be entirely fair; ‘Mammoth Lavender Daisy’ may have looked terrific a few weeks earlier although two plants in the same series really should flower more or less together.

The bigger question is how, exactly, do we use these footstool chrysanthemums in the garden? Their tight hemispherical shape makes them almost impossible to group with other plants. I once saw them planted on a slope, tight against some steps, and they softened the jagged line of the steps beautifully. But you couldn’t use them in an autumn border with other perennials.

Personally, I prefer the older American chrysanths.