Any idea what teratology is? I’ll tell you: “the study of abnormalities of physiological development”. And for almost twenty years Martin Barber, from Wiltshire in the west of England, has been producing a newsletter devoted to abnormalities in plants. It’s called That Plant’s Odd. Says it all, really.

The newsletter deals with unusual forms of mainly wild plants and, as the introduction to the very first edition in 1993 says: “The scope of the newsletter is to include any material concerning native plant aberrations.” That is: odd plants. Variegations of various kinds feature often, as well as yellow- and purple-leaved forms, and there are plants with flowers in unusual forms or in unexpected colours; as well as plants with contorted branches or with strangely formed flower spikes. Anything that is, frankly, just a bit odd. The yellow-leaved form of the British native stinking hellebore, Helleborus foetidus ‘Chedglow’ (above, click to enlarge) is one of Martin’s finds.

That very first issue of That Plant’s Odd includes records of a white annual corn poppy with red blotches at the base of the petals (sounds gorgeous), of wild elders with pink flowers and another with purple stems, while issue two discusses two variegated wild roses, variegated dandelions, and forms of the classic British native bluebell with leafy growth amongst the flowers.

I’ve found a few plants that qualify, over the years, including two or three very attractive lawn daisies with yellow leaf veins one of which was in a lawn at the National Botanic Gardens in Dublin. Last spring, at the Barnack Hills and Holes Nature Reserve, I came across just one plant of the common British woodland flower, Dog’s Mercury’ (Mercuralis perennis) which was almost completely yellow (left, click to enlarge).

It’s also worth remembering that many of today’s most dramatic varieties of Heuchera are derived from unusual forms collected from the wilds of the American forests.

As well as publishing That Plant’s Odd, which I have to say is more appreciated for its content than for its elegant design, Martin also runs a small nursery specialising in these unusual plants called Natural Selection and is the author of Appreciating Lawn Weeds and of Botanical Monstrosities: A First Step in Plant Teratology though both these are hard to find.

A two year subscription to That Plant’s Odd (six issues) by costs just £7.00 for British subscribers. Send a cheque to: That Plant’s Odd, 1 Station Cottages, Hallavington, Chippenham, Wilshire, SN14 6ET. Martin hopes to be able to deal with international subscriptions soon.

Last I week I was enthusing about Simply Perennials bringing lots of great new American perennials to the UK for the first time and I was also reminded of an article in Britain’s Daily Telegraph newspaper a few weeks ago saying, basically, that American plant breeders had taken over the world.

But British plant breeders not only have a great history of new introductions going back hundreds of years but in Britain there’s still a huge number of nurseries and plant specialists developing new plants. Although in North America it’s often not clear that these plants are actually British. So perhaps an American company should specialise in bringing new British plants to North America?

Many of Britain’s best are already have their plants doing well in North America. Raymond Evison’s clematis are much admired. Blooms of Bressingham continue the great tradition begun by Alan Bloom eighty years ago. There are Tumbelina double petunias, and singles too, from David Kerley; begonias from Fred Yates are everywhere; David Austin trials his new roses in the US, as well as the UK, and recommends varieties specifically for North America; many of the plants created by Charles Valins, at Thompson & Morgan from echinaceas to the first blue verbascum (as well as buddleias and hollyhocks), are popular in the US.

There are also companies like Whetman Pinks who develop new varieties of garden pinks of all kinds; Peter Moore works on shrubs, Joe Kennedy works with primroses. David Tristram is a leader in hellebores with his fine hybrid of H. niger and H. x hybridus, and has other valuable introductions. Patrick Fitzgerald in Ireland has some good things on the way.

In vegetables companies like Tozer and Elsoms are world leaders and smaller companies led by people like John Burrows and Simon Crawford are leaders in patio tomatoes. Britain is also a leader in strawberries, raspberries, and other fruits while in Floranova and Vegetalis Britain has one of the most innovative creators of new annuals and patio flowers and vegetables.

I apologise to the many many other accomplished creators of other new varieties for not mentioning them; that’s the thing, there are just so many – delphiniums, sweet peas, peppers, irises, caryopteris, the list goes on. Perhaps an American nursery needs to start a Best of British brand.

In the picture (click to enlarge): Begonia Million Kisses Elegance (‘Yagance’), Clematis ‘Josephine’, Geranium Rozanne (‘Gerwat’), Rosa Molineux (‘Ausmol’) and Verbascum ‘Blue Lagoon’

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.

“New” is the salesman’s favourite word. It’s the word that gets us to look even if it doesn’t always get us to buy. Doesn’t matter if it’s a TV show or a plant, if it’s new we usually pay attention.

Perennials have become amazingly popular in recent decades and new perennials are now being developed all over the world. Laboratory techniques enable them to propagated in large numbers very quickly. Terra Nova Nurseries in Portland, Oregon (who are not retailers) produce over six million young plants a year and have become famous for the huge number of new varieties of perennials they’ve created in the last twenty two years. And from their early days they sent plants to nurseries in Britain.

Heucheras have always been a focus and their varieties have been carried in particular by two British specialist nurseries with the splendid names of Plantago and Heucheraholics. Other species have been carried by a range of mail order nurseries but now a new venture, Simply Perennials, is developing a mail order range focusing on varieties from Terra Nova.

Simply Perennials is a part of Simply Seeds and Plants which began with sweet peas, added fuchsias, chrysanthemums, patio plants, bulbs, and vegetable plants and has now added perennials. At the last count about half the perennials in their range are varieties not available from anywhere else in Britain. I was especially pleased to see new kniphofias, an amazing new corydalis, a lovely new rudbeckia for cutting and borders, and what looks to be a dramatic red-stemmed variegated hosta. Simply Perennials will be adding new varieties from other sources as they enhance their range.

But here's the thing: while it’s great to see new American perennials available for the first time in Britain – what about the other way round? There’s a huge wealth of new perennials, and shrubs and climbers, being developed in Britain – perhaps an American specialist should make them the focus of a new mail order business.

In the picture (click to enlarge): Kniphofia 'Papaya Popsicle', Hosta 'Raspberry Sundae', Corydalis 'Blue Heron', Rudbeckia 'Little Henry'.

Producing a guide to America’s (and Canada’s) gardens comes with both the advantages and disadvantages of a broad North American sweep. It ensures that wherever you travel the book has an interesting visit to suggest, but some states have so few entries that they may all be hundreds of miles from where you happen to be.

Entries are crisp and to the point, with symbols to highlight many features, and there’s enough to tempt you to look for more information on those that are especially appealing. But: “Smart-phone scannable QR codes that link to every garden’s website,” says the back cover and the publisher’s website. No. Of nine entries for South Carolina, a state picked at random, only three gardens have QR codes.

I can’t help but feel that the information should come not only as this useful book but as an app and a website where you can just put in a zip code (postcode) and see what’s nearby.

• A useful throw-in the-suitcase book for American and overseas travellers.
• Needs an app and website which includes far more gardens

The Visitor’s Guide to American Gardens by Jo Ellen Meyers Sharp is published by Cool Springs Press.

The great British plantsman E A Bowles once posed this question: “Suppose a wicked uncle,” he wondered, “who wished to check your gardening zeal left you pots of money on condition that you grew only one species of plant: what would you choose?”

Then the great man answered his own question: “I should settle on Iris unguicularis,” he answers. And, considering the extraordinary range of plants he grew at his garden at Myddelton House in north London, we should respect his choice.

It’s a zone 7 plant so not hardy here in Pennsylvania - well, it grows wild in North Africa - so one of the treats of going back to zone 8 England in winter is the chance to see them, and smell them too for their fragrance is wonderful. Bowles chose this plant, long ago known as Iris stylosa, as the first flower of spring and from October onwards in Britain in zone 8 the flowers appear: purplish or true blue, lavender or white, building up to a crescendo in February or March when you can gather enough flowers from a single clump to enjoy indoors and the leave the plant in the garden apparently unplundered.

There is an art to cutting these flowers for what appears to be the stem of the flower is actually an unexpectedly elongated part of the flower stem itself and only at ground level is there 3/4in/2m of true stem. Each stem usually carries not one, but three flowers. So, if you simply slice off the flower as low down as you can possibly go – and that is certainly the temptation – you will cut off those extra flower buds. But if you slide your fingers down the stem you’ll feel those other buds; cut just above them.

‘Mary Barnard’ is dark blue, ‘Walter Butt’ is a soothing, cool, pale pearly lavender while ‘Alba’, the white form can be shy. They’re all lovely.

If you’re fortunate enough to have a suitably warm border, perhaps just a narrow 2ft/60cm strip in front of a sunny wall, then Iris unguicularis will repay your planting it there with plenty of flowers. Add pink Nerine bowdenii and the white crocus-like Zephyranthes candida and the bold trumpets of Amaryllis belladonna (not those indoor monsters, the hardier one) and Agapanthus for the summer and you’ve created a border for almost al the year. Scatter a few seeds of the dainty little creamy California poppy, Platystemon californicus, and you’ll have to open the garden specially for visitors to come and admire just this one border.

But Iris unguicularis, the first choice of a long gone master plantsman, E. A. Bowles, is worth growing even without them.

In Britain, Avon Bulbs list six varieties. In North America, Plant Delights list two tempting varieties (scroll down), while Mount Pleasnt Iris also list two (scroll down).