Nature Near London: Snowberry (Symphoricarpos albus)

Snowberry growing in Ham Common Woods Local Nature Reserve, January 2012

Our efforts in 2012 clearly diminished the snowberry, but it's still there.

Snowberry growing alongside Burnt Oak Brook in Watling Park, Northwest London, July 2009

Snowberry (Symphoricarpos albus) is described by E.J. Clement and M.C. Foster as "an established garden escape, naturalised in many places throughout the British Isles", in Alien Plants of the British Isles (Botanical Society of the British Isles 1994). Named after its large white berries, the species is native to the western United States, where rather ironically conservation organisations have programmes of snowberry restoration.

Although probably significantly less invasive in the British Isles than plants such as Himalayan Balsam (Impatiens glandulifera) or Rhododendron (Rhododendron ponticum), snowberry is quite widely found in woodland as it was apparently planted for game cover in the 19th Century. However, it does have the ability to form dense deep-rooted stands that are difficult to remove manually. Given the need to apply the precautionary principle when dealing with invasive species, removal is recommended. To kill the entire plant including the roots, ideally a herbicide such as glyphosate should be applied when the plant is in full leaf, although manual removal can also be effective. Removal of snowberry should allow native plants to recolonise an area. It will be interesting to see whether cutting is sufficient to remove the plant, or whether the rhizomes need to be dug out. There appears to be little research into the impacts of snowberry in the British Isles. (By 2013, it's clear that cutting is not sufficient, roots need to be dug out).

It is hard to know how the snowberry in Ham Common Woods got there, as the common was grazed until the 19th Century, although as the patch is alongside a watercourse, it is possible that seeds were carried downstream from Richmond Park.