Pokeweeds
What are they?
The pokeweeds are members of the family Phytolaccaceae, a family mostly found in the tropics and warm-temperate regions of Asia and the Americas. A number of species have been introduced into the UK, mostly as garden ornamentals, but there has been much confusion over the true identity of many of these. Plant taxonomists continue to research and refine the species limits and identification criteria, particularly of the Asian species, which seem to be particularly difficult to determine satisfactorily. Although there are tree species in the tropics, plants in the UK are all herbaceous perennials that form large root systems and send up succulent, branching shoots from the base each year.
Where are they found?
As escapes from cultivation, these plants might turn up anywhere, but typically appear close to gardens or in urban environments. Small populations have been recorded in most of the larger towns and cities of the region over time, but these seem to disappear after a few years and the fluctuations in popularity of these plants causes regular peaks and troughs in the likelihood of finding them growing in the wider countryside.
Identification
As mentioned above, the identification of pokeweeds in the UK has been beset with problems due to disagreement over the best identification criteria and plants have regularly been reidentified in the past. Current understanding is used here (but may change!) and uses mostly details of the flowers to determine the species. Check the number of stamens in the flowers (tahe a count from a range of flowers to account for any variability) and whether they appear in one or two rows. Also check whether the carpels are free or are fused together. The carpels are the swollen bases of the stigmas and form a rounded, green bump at the centre of the flower (these become purple-black after fertilisation and form the fruits, so can be checked in fruit, too). Finally, check whether the fruiting spikes are upright or hanging.
Indian Pokeweed Phytolacca acinosa
Introduced from eastern Asia and probably the most common species in cultivation. Has been widely recorded in our region as a garden escape. Flowers July to September. Flowers pale green to cream, or pink, often darkening with age. Carpels 6-9, free, forming a ring of segments like a small blackberry as they ripen. Stamens 8-10 in one or two whorls (this variation may suggest that more than one species is included under this name). Fruiting spikes remain upright.
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American Pokeweed Phytolacca americana
Introduced from North America. Has been recorded in our region as a garden escape a handful of times but questions remain as to the correct identity of such plants. Flowers July to September. Flowers usually whitish, becoming pink with age. Carpels 10, fused, forming a single berry as they ripen. Stamens 10 in one whorl. Fruiting spikes become pendulous as the develop.
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