Sycamore? Or sycamore?

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

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.

Classic tree and shrub reference goes online

Bean's Trees and Shrubs Online.The five volume Trees and Shrubs Hardy in the British Isles by W. J. Bean, usually referred to simply as “Bean”, is a monumental work running to over 4,000 pages. It does what it says: it describes in detail the woody plants (including climbers) that can reasonably be expected to grow outside in Britain (mostly zone 8, some zone 9).

The four A-Z volumes were last revised almost forty years ago, then a supplement appeared in 1988 (see below, click to enlarge), so it does not include recent classification and name changes and recent introductions. Otherwise, it's impressively comprehensive with good descriptions and boundless information on origins and differences between similar plants. It’s invaluable.

Now you can read it - free.

In the first part of a two part initiative, the International Dendrology Society has published the whole thing – all 4,027 pages of it – online. And it’s free: no charge for access. The original four A-Z volumes plus the supplement are currently priced on at £325/$504. Did I mention that the online version is free?

The new online version is easy to navigate and attractively presented. The next step is adding pictures.

You can read more about it on the excellent blog post by John Grimshaw, who’s been heavily involved with the project - and I see he’s had the same idea of including an image of his five volume set as I did!

Take a look at Bean's Trees and Shrubs online - it's invaluable, and it's free.

The five volumes of Bean's Trees and Shrubs. Image ©

And what's coming next? Britain's Alpine Garden Society is well into the process of making its invaluable two volume Encyclopaedia Of Alpines available online. It's currently available from for £150/$250.74. You can track the progress of the operation here.

Book Review: Trees and shrubs - a new edition of the essential reference

Hillier ManualOf Trees and Shrubs - new edition now outThe classic British* reference book on trees, shrubs and climbers is The Hillier Manual of Trees and Shrubs. My copy sits with a small and very select group of references just to left of my computer monitor; I probably use it every day.

Now, a new revised edition of this classic has been released by the Royal Horticultural Society, twelve years after the last edition. It has been significantly updated and expanded to include an amazing total of 13,215 individual plants (plus 3,258 cross-references and synonyms) from 706 genera; 1,490 plants have been added to those in the previous edition and this confirms the book’s status as the essential reference on woody plants for British gardeners.

As you can tell, it’s comprehensive. I’ve only failed to find one shrub I’ve looked up over the last few months and believe me I check on some pretty unusual plants. Another thing is that, as with my Encyclopedia of Perennials, the descriptions are written in accessible language – you don’t need to be a professional botanist to understand what’s being said. So no words like “bipinnatifid” and “orbicular” except where absolutely necessary (and of course there’s an easy glossary).

Wherever possible the text notes when species were introduced to western gardens, who discovered them in the wild and who introduced or developed cultivars and other interesting snippets of information. I’m pleased to see that plants which have been awarded the Royal Horticultural Society’s prestigious Award of Garden Merit (AGM) are marked but plants are not given hardiness ratings – not the USDA ratings nor the new RHS ratings. I’m told that the RHS hardiness ratings will added in a future edition.

This medium format book has no colour pictures, and so is priced at under £20 for almost 600 pages of the highest quality information. And it’s worth mentioning that commenters on are comparing the book unfavourably with previous editions because there are no colour pictures. But as far as I’m aware the Hillier Manual never had colour pictures; they’re confusing it with the old, extremely outdated and much less useful Hillier Colour Dictionary of Trees and Shrubs and Hillier Gardener's Guide to Trees and Shrubs which included many colour pictures – but covered far far fewer plants.

And, as Roy Lancaster says in his preface: “Even without illustrations, it offers a window on the wonderful world of woody plants to be seen, admired, cherished and ultimately enjoyed.”

But one thing that disappoints me. Bamboos are included, over thirty pages of Rhododendron hybrids are included, there are seven pages of Clematis hybrids – but only ten pages of roses, and none of the huge number of hybrid roses that are so widely available. Considering that in much of the country it’s impossible even to grow rhododendrons (because they need acid soil), to include so many seems perverse when at the same time excluding roses – which anyone anywhere can grow.

The RHS tell me that this is a matter if history - Hillier Nurseries, who developed the original manual in 1971, were never big on roses - and also that modern rose introductions disappear so quickly it would be impossible to keep the book current. My view is that while roses may not have been important to Hillier Nurseries, they're very important to gardeners and including old roses, or AGM roses, at the very least, would have been very helpful.

Finally, let me mention the book’s stout binding (although it’s a paperback it should last like a hardback), its clear typography and layout, and its valuable updated lists of plants for purposes. Excellent.

In all, this is an essential reference, with far more information for your money than any other guide to trees and shrubs.

* I should make clear that, while the book is intended for British gardeners, serious enthusiasts for shrubs in North America and around the world will find plants and information included that are in no other reasonably priced guides – or, in many cases, in any other guides at all.

The Hillier Manual of Trees and Shrubs is published by the Royal Horticultural Society.


Conifer Society website review

American Conifer Society website home page
Plant society websites are sometimes - well, how shall we put it? – not very tempting, especially those of smaller societies. So, when I heard that the American Conifer Society had totally revamped its site, I gave it a little time to get the bugs out and I then took a look. And what a pleasant surprise.

The home page is appealing, colorful and contemporary, clean and uncluttered, with a navigation bar across the top and panels listing Events (Society events), What’s New (revealing how active the Society and its members are on the site, with regular additions, blog posts and discussions), and Videos (interesting, but could do with a technical upgrade).

The nuts and bolts of the Society’s organization and its activities are presented with the same attractive look, easy-to-read text and with clear and helpful secondary navigation. So often this part of a society’s site looks dull and far from enticing but the simple and elegant design works well.

The Discussion button brings us to a wide range of topics from the all-too-familiar deer problem, to plant identification, propagation and pests and to current queries such as whether it’s wise to knock accumulated snow off conifer branches. Sensible questions with thoughtful answers. All the discussions are available for anyone to read, but only Society members can ask questions or post replies. There are blogs too; posts are not frequent but they’re well written and genuinely interesting.

There’s a button for Regions, with material from the four regional chapters, and then the tantalizing button American Conifer Society website Conifer Database entrythat says simply: Conifers – where it all unfolds. Here you’ll find lucid background on size, shapes, uses and naming of conifers – plus the Conifer Database. This is a searchable database of information about conifers, and pictures, provided by the Society and augmented by its members – especially in terms of pictures.

You can search by conifer size, habit etc. or you can pick out a particular genus, species or cultivar to find out about. This is building into an invaluable resource - especially with the benefit of images uploaded by Conifer Society members which can give a far more comprehensive understanding of how a plant looks at different ages and different seasons than any book. But at present it’s a work in progress. The hardiness zone maps need to be clearer and many individual cultivars still have neither words nor text. So if you grow conifers, join the American Conifer Society and add to this expanding resource.

Like most plant society websites, the American Conifer Society site is built and supported by the society’s volunteer members. But, unlike some, this society has built a site that is appealing to potential members in its look and its content and also provides a valuable platform for its members to advance their enthusiasm for conifers, and exchange ideas and solutions to problems. And so much information is also available to the rest of us that it helps us all grow better conifers and tempts us to join.

You can join the Conifer Society here.

Spectacular new conifer encyclopedia


I’m awestruck. This is a most extraordinary book. And having myself edited an encyclopedia that ran to half a million words and 1500 pictures – I can tell you that just putting this book together so beautifully and getting it out at all is an amazing achievement. Then, as soon as you open it, you see how valuable this book is.

Seventy three genera, 615 species and around 8000 cultivars are presented in two volumes totaling 1508 pages in a format that’s noticeably larger than all the other familiar plant encyclopedias. Oh, and did I mention there are over 5000 color photographs? Five thousand! And if you thought you weren’t really very interested in conifers, those pictures will convert you in moments. The full page image of the big blue cone of Abies koreana (above, click to enlarge) is stunning. I want one. And it’s so unusual to be able to see so many examples of the same cultivar illustrated at different times of year.

ConiferEncyclopediaBooks600As a guide to how comprehensive this book is, it includes (by my count) one hundred and ninety three cultivars of the US native Eastern White Pine (Pinus strobus) (P. strobus 'Louie' below, click to enlarge) and two hundred and three cultivars of the British native Scots’ Pine (P. sylvestris). I don’t dare count the entries under Lawson’s Cypress (Chamaecyparis lawsoniana) but they cover almost thirty eight pages. So yes, it’s comprehensive. And all the classification and naming is all bang up to date.

Clearly and attractively laid out, the pictures are superb, with those used at full page providing a fine appreciation of the detail of cones or foliage or the habit of the plant. A very useful feature is that a height and width after ten years is given wherever possible. The extensive cross referencing of synonyms and even mis-spelled names is extremely valuable, they even note where every single picture was taken – at one hundred and twenty one different gardens around the world. Talk about thorough…

Put together by the Latvian conifer specialist Aris G. Auders and Derek P. Spicer, Chair of the PinusstrobusLouie900 British Conifer Society, over just seven years, they travelled the world examining and photographing plants and checked every scrap of serious conifer literature. The book is published in co-operation with the Royal Horticultural Society with expert editing especially from from Victoria Matthews, as well Mike Grant and Lawrence Springate, formerly RHS International Conifer Registrar. Quite a team...

Of course, this is not a book for everyone (the publishers' price is £149, after all), it’s far more than most gardeners need. But this is going to be powerfully influential book. Every college horticulture department across the world, every university botany department, every horticultural and botanical institution across the world, every conifer nursery, every major horticultural society – they should all have it. Every garden writer who writes about conifers should have it too. And many garden designers will find the vast variety of shapes and textures and colors on show inspiring. My copy is not leaving this room!

If you really want to know everything there is to know about conifers, start with this book.

The Royal Horticultural Socity Enclyclopedia of Conifers by Aris G. Auders and Derek P. Spicer is published by RHS/Kingsblue Publishing.

This book was published in Europe some time ago, but only now is there a guaranteed supply in North America. I waited to review it until it was generally available.


Although these are very heavy books, as I write still only charges $3.99 for shipping and in Britain delivery from is free! This, of course, may change.

Distinctive trees of our local forests

Sassafras albidum (left) and Liriodendron tulipifera: two fine trees of the eastern American forests. Image ©
Two native trees of the eastern American forests have leaves which you just can’t confuse with anything else. Both feature fine fall color (although they're now past their peak) and both make fine specimen trees for gardens, on both sides of the Atlantic.

On the left in the picture (click to enlarge) the quirkily lobed leaf of Sassafras albidum. Kids call it the mitten tree, especially as seedlings may only have two lobes. We have a dying tree – one huge woodpecker hole is causing it to rot from the inside – but it’s inside the deer fence so its seedlings are popping up all over. Outside the fence – none.

Ours all seem to color yellow or orange, some with a few purple veins, but fall color on other trees can be a vivid red. And although we have plenty of seedlings they’re almost impossible to transplant. Suckers seem to work better. And it insists on acid soil.

The tulip tree, Liriodendron tulipifera (above right), seems more widespread across the river from here in New Jersey although there are a couple of young trees by the side of the road a few miles away and farther afield in Pennsylvania it’s moved in to take the place of all the chestnuts that died of blight. Again, its leaves are very distinctive – but very different – and its fall color is yellow to old gold.

Tulip tree develops into impressive straight-trunked specimens, the tallest in our state is 133ft/40m. Sassafras develops into bushier specimens, half the size.

Both these trees have many other valuable features, but as fall fades these are two of the most distinctive trees of our local forests and impressive in gardens too – if you have the space.

British gardeners can order Sassafras albidum from these RHS Plant Finder nurseries.

British gardeners can order Liriodendron tulipifera from these RHS Plant Finder nurseries.

North American gardeners can order both these trees from Forest Farm, and they're also sometimes available from local conservation groups.

Doll’s eyes and tulip trees

Actaea pachypoda, Doll's Eyes; the fruits weigh down the stem. Image ©
Just a quick post to show you these amazing fruits that we spotted on a woodland walk at the weekend. The plant is Actaea pachypoda, also known as Doll’s Eyes or, more prosaically, as White Baneberry, and we came across just one plant, its two shoots weighed down by these spectacular berries.

This is one of those plants that used to be seen far more often until the deer population grew so dramatically that in much of our area the ground flora has been decimated. The whole plant is poisonous, but that doesn’t seem to deter the deer. There’s an interesting discussion of this and the other North American Actaea in the exceptional Spring Wildflowers Of The Northeast by Carol Gracie.

In the garden this is a fine shade plant, especially when it's matured into a fat clump  - although here in Pennsylvania the fruits - which follow white fluffy flwoers - tend to rot before they reach their full glory; I think our plant is too crowded and overhung by shrubs.

The other fine sight at Tillman Ravine in New Jersey was a huge tulip tree, Liriodendron tulipifera, its fall foliage bright yellow high against the blue sky, way above the trickling creek. I remember the one at Kew, planted in 1770! Great to see such a fine specimen in the wild (but impossible to photograph).

In North America you can buy plants of Actaea pachypoda from The Tree Nursery

In Britian you can buy plants of Actaea pachypoda from these RHS PlantFinder nurseries

Book Bullet: Dirr’s Encyclopedia of Trees and Shrubs by Michael A. Dirr

DirrTreesShrubs9780881929010lI 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

Beautifying Britain's roads

Flowering cherry planted by the Roads Beautifying Association fifty years ago. Image ©GardenPhotos.comAlong a busy road near Hampton Court Palace, King Henry the Eighth’s sixteenth century residence on the southern edge of London, there are some cherry trees. All the way along a wide straight stretch of suburban road, on both sides. But these are not any old cherry trees.

They represent one of the successes of the Roads Beautifying Association which was set up in 1928 to improve the look of the many new roads being built as cars became more popular. Its dedication to roadside planting was the contemporary equivalent of the current enthusiasm for planting wildflowers along new roads. Interestingly, part of their rationale for tree planting along roads was to stop drivers being distracted by looking at the landscape.

It’s years since I’ve been in England at the right time to see them in flower, but it’s obvious that those cherries are now well past their best. I’d say that they were planted in the 1950s so many have already died; cherries are relatively short-lived trees. But trees that have died have been replaced, and it’s clear that the remaining trees are being looked after. I suspect that without the historical connection they would all have been replaced but instead some careful tree surgery has been undertaken and even those with only a few branches remaining have been retained.

Planting blowsy Japanese cherries along new roads would be frowned upon now. But the Roads Beautifying Association began convinced people that roads needed beautifying, did the job and even produced a book called Roadside Planting.

One final interesting point. The Roads Beautifying Association, which finally ceased to exist in 1963, was founded by a dermatologist called Wilfrid Fox. He also founded and planted one of the finest arboretums in Britain, at Winkworth in Sussex. And my dad and I used to fish for trout in the lake at the arboretum before I was ever interested in plants.

Flowering cherry planted by the Roads Beautifying Association fifty years ago. Image ©



Book Bullet: The Art of Creative Pruning by Jake Hobson

Review: The Art of Creative Pruning by Jake Hobson ISBN:9781604691146lEven 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.