On both sides of the Atlantic, independent trials of perennials are organized by a number of different organizations. But I’ve sometimes seen the Royal Horticultural Society’s Award of Garden Merit (AGM), often given after trial (phlox and sweet pea trial, above), used in American catalogs and wondered how much relevance this British award has in North America. And does the Plant Evaluation Program run by the Chicago Botanic Garden and, in Delaware, the trials run by the Mount Cuba Center (baptisia trial, below) have any relevance in Britain?

Well, this year I’m chairing a group of experts working to update the list of AGM heucheras for the Royal Horticultural Society (RHS) and I’ve sent all the participants copies of the reports of the heuchera trials at both Mt. Cuba and the Chicago BG.

Of course, the climate in Delaware and in Illinois is, well, rather different from the climate in Britain but, for hardy perennials, if they grow in Delaware or Illinois, they’ll generally grow in Britain. And while modern American heuchera breeding is often focused on suitability for specific climates, the way the plants look when they’re growing well is relatively constant; a harmonious combination of flowers and foliage works well in any climate. So these reports will provide valuable background to our deliberations.

At first I was skeptical, but now I can understand why the AGM appears in American catalogs – it’s one of a number of useful factors that inform choice. The problem is that some gardeners in Texas or Maine, while they may see that the plants look wonderful, may not appreciate that the plants are given their award in a climate that’s closer to that of Oregon or Washington state may not do well for them. In fact they may die their first year.

But it’s not just climate, there’s another thing going on. I suspect that most British gardeners, seeing trial results from Delaware or Illinois, will just assume that they’re of no relevance, or even interest, and ignore them. True, disease resistance in American trials is unlikely to be of value elsewhere as different forms of the same disease are found in different places. But if the flowers are a dingy color in Chicago they’ll be dingy in Britain, too

American gardeners, on the other hand, seem to have a more open attitude and although they may not want to read the detailed reports of the RHS trials in which plants were given the AGM, they’re happy to accept that this is useful information and allow the awards to inform their plant choices as they decide what’s right for their own gardens.

And perhaps, as the dissemination of information about plants becomes more global, these reports help writers and advisors and consultants develop a deeper understanding of the plants so that the guidance we pass on is more informed. And they help nurseries decide what to grow. These trials and their reports are certainly invaluable to me. Even something as simple as paying attention to the factors these reports consider important is useful.

* The Mount Cuba Center is based near Wilmington, Delaware, just over an hour north of Washington DC, and its primary aim is to foster enthusiasm for native plants and their conservation. You can download their trials reports here.

* The Chicago Botanic Garden has been organizing trials of hardy perennials, and other plants, since 1985 under the expert guiding hand of Richard G. Hawke. You can download their trials reports here.

* The Royal Horticultural Society has been running trials of everything from hamamelis to cabbages to marigolds since, it seems, time began. You can search their database of trials here.

Yes, really!! The whistling snowdrop! Let me explain.

Every year since 1929 the Royal Horticultural Society has published the Daffodil, Snowdrop and Tulip Year Book. It began as the Daffodil Yearbook, became the Daffodil and Tulip Yearbook in 1946 and more recently has added snowdrops.

I’ll tell you more about it in a moment but what about this whistling? Well, in the latest issue, there’s a short review of a German book called Schneeglockchen-ABC (The ABC of Snowdrops) by snowdrop wizard Matt Bishop. Here’s what he says:
“There is really only one way to describe Schneeglockchen-ABC: as very curious indeed... The text seems to be formed from a conscious and strange juxtaposition of fact and the wildly fictitious, with no attempt to differentiate them.… This is highlighted very early on, under the entry for a supposed cultivar ‘Alert’ which, translated, claims to be “described by Matt Bishop as the first snowdrop to produce loud whistling tones.”

He goes on to say, with remarkable restraint, it seems to me: “Much of the information… would have benefited from checking at source. The resulting text is marred by so many errors of information and spelling that it cannot be relied upon for accuracy.”

But let’s set that aside and point out the international value of this splendid annual. There’s a really useful summary of the rules governing taking plants to and from the UK, USA, EU and elsewhere; a fascinating piece on the wild daffodils of Morocco together with an overview of fifty years of daffodil breeding by Brian Duncan. Alan Street outlines how to start a snowdrop collection, there are reports from two tulip festivals in Yorkshire as well as from shows in Australia, New Zealand, various parts of Britain as well as the World Daffodil Convention held in St. Louis, Missouri.

There’s science, taxonomy, practicalities, conservation, awards and other info for both the serious expert and the enthusiastic newcomer. And the photography is excellent. And then there’s the whistling snowdrop. A splendid winter read.

* Unfortunately I’m able to provide you with a photograph of the legendary whistling snowdrop. So please enjoy Alan Street’s startling image of the variety ‘South Hayes’.

In the UK you can order the 2016 RHS Daffodil, Snowdrop and Tulip Year Book from the Royal Horticultural Society book store. They will also send copies anywhere in the world.

In North America you order the 2016 RHS Daffodil, Snowdrop and Tulip Year Book from the American Daffodil Society.

And if you should want to order a copy of Schneeglockchen-ABC by Maria Mail-Brandt it's available from amazon.co.uk and also available from amazon.com. And don't forget it's in German.