Japanese Knotweed Solutions Ltd. Blog "Growing Concerns"

Hybrids aren’t just funny looking cars...

April 24th 2015

Have you seen the film ‘Blade’ with Wesley Snipes?

Wesley has all the strengths of a vampire whilst keeping the ability to be a ‘day-walker’ and isn’t killed by sunlight. So he has all the positive vampire traits and doesn’t have any of the weaknesses (apart from a hunger for human blood which he counteracts with a specially devised serum that he injects) ...so he is a hybrid...that thrives to the determent of all of his enemies.

Hybridization is the fundamental mechanism by which rapid evolution can occur in invasive species. If a hybrid shows increased vigour this would significantly contribute to invasion success.

CABI (www.cabi.org) have carried out a comparison of Fallopia japonica and Fallopia sachalinensis and the hybrid Fallopia x bohemica in competing against experimental communities of native plants. It was found that the knotweed hybrids performed significantly better in competition with a native community and that they strongly reduced the growth of native plants.

Of the parental species F. sachalinensis regenerated significantly from rhizomes suggesting allelopathic* inhibition by native plants.

The study found great variation between the various taxa but the hybrid proved to have the greatest success – thus proving that invasive knotweed hybrids are indeed more competitive than their parents.

We already know that Japanese knotweed has no natural enemies in the UK – (apart of course from the Psyllid aphid released by CABI as part of the Government bio-control strategy) – so with a mutational hybrid being even more efficient at spreading than the all-ready prolific plants that we struggle to manage – we could be in an even worse position...


Mike C

With thanks to CABI


NB: *allelopathy is the secretion of chemicals by plants to inhibit growth of other species