Notes From a Sceptical Gardener by Ken Thompson

Author:Ken Thompson
Language: eng
Format: epub
Publisher: Icon Books
Published: 2020-01-15T00:00:00+00:00

Gooseberries; aliens in our midst

A book I really enjoyed reading last year was one of the latest in Collins’ New Naturalist series: Alien Plants by Clive Stace and Mick Crawley. Every chapter told me something I didn’t know, but perhaps my favourite was ‘Our top fifty-two neophytes’. Neophytes are what botanists call alien plants that only escaped into the wild after 1500 (introductions that escaped into the wild before that date are called archaeophytes).

First of all, why 52? Well, almost the only really objective measure of commonness is to count how many hectads a plant is found in. A hectad is a 10 × 10 km Ordnance Survey grid square, and there are about 3,859 hectads in the British Isles. So a reasonable definition of a common neophyte is one found in at least one-third of them (1,286), of which there are 52, or just 2.87% of the total. The great majority of neophytes are much less common; in fact only just over a third are found in more than 1% of hectads.

Most neophytes started out as garden plants, and many would be a lot commoner if you included planted specimens in gardens, but we’re talking here about abundance in the wild. Nevertheless, the authors of Alien Plants are sorry to have to report that top of the list is not an escaped garden plant, but the very unprepossessing pineapple weed (Matricaria discoidea). First reported in 1869, pineapple weed is now a universal inhabitant of trampled bare ground; indeed it’s the only neophyte that’s found in over 90% of hectads.

Number 2 on the list, just short of 90%, is sycamore, and number 3 is snowberry, Symphoricarpos albus. Already you can see that our commonest neophytes have very little in common, and are a complete mixture of weeds, herbaceous perennials, shrubs and trees. You may have been slightly surprised to find snowberry so near the top, but neither the second commonest alien shrub (Rhododendron ponticum) nor the fourth (buddleja) will surprise you much. But the third might: Ribes uva-crispa, gooseberry.

Gooseberry is so common in hedgerows and scrub that you might have assumed, if you ever thought about it at all, that it was native. In fact gooseberry has often been claimed as a native; Richard Mabey, in Flora Britannica, states categorically (and wrongly) that it is native. Gooseberry was certainly in cultivation by 1275, but it took a long time to escape. Gerard, in his famous 1597 Herball, describes it as well-established in gardens, but said it had no name amongst old writers who either ‘knew it not or esteemed it not’. It was not recorded in the wild until 1763.

Like many plants that have been cultivated for a very long time, the original native range of gooseberry is uncertain, although it’s certainly European. But in a more recent twist to the gooseberry story, our plants probably now contain a few genes from significantly further afield. The reason is that in 1905 the European gooseberry faced a new and serious problem, when American gooseberry mildew (AGM) was accidentally introduced.

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