I don’t know which day is the most exciting: the day the first spring flower opens after months of snow or the day (not long after, back in Pennsylvania) that the new annual edition of the Royal Horticultural Society’s Plant Finder comes out.

Well the witch hazel, the snowdrops, the first crocuses and the good old skunk cabbage are flowering in Pennsylvania and now we have the new Plant Finder so spring has well and truly arrived.

Just to recap, the new Plant Finder is basically a list of over 71,000 plats available from British nurseries (71,177 to be precise) with sources indicated for each one and with every name checked for accuracy. So outside Britain it’s invaluable as an annually updated record of the correct names for this vast variety of garden plants.

One of the many interesting aspects of the book is to see which of the brand new plants is listed by the most nurseries. It’s a really good guide to the hot new plants.

So, what’s the top new plant this year? (Drum roll….) Gaura lindheimeri 'Rosyjane' with ten nurseries listing it in the new Plant Finder. I featured in last year’s pre-Chelsea Flower Show coverage and in my Hampton Court coverage. It’s gorgeous.

Close behind is Sedum ‘Mr Goodbud’, which won an Award of Garden Merit in the recent RHS trial. This is followed by a perennial becoming familiar to American gardeners, Echinacea ‘Tomato Soup’ raised at Terra Nova Nurseries in Oregon who also raised the next on the list, x Heucherella 'Tapestry' which is equal with Clematis Diana's Delight ('Evipo026'), raised by clematis wizard Raymond Evison, and next, perhaps most surprising of all, a tree Sorbus commixta Olympic Flame ('Dodong'). Quite a mixture of new favourites.

You can find which nurseries stock these plants – and what the correct names are for all 71,000+ of them, by buying a copy of the RHS Plant Finder. Or take a look at the online version – it’s free. Yes, the online version is free - and may it always be so – and it includes, by the way, records of all the plants which have been listed in the past but which are no longer included – nearly 45,000 of them.

Yes, spring has finally arrived. The new RHS Plant Finder is out.

British gardeners can buy the RHS Plant Finder here

But North American gardeners (gulp) will have to wait to get it from amazon.com as they do not yet list it. The shame!! Of course, you can always get it shipped over from across the Atlantic.