Sometimes it’s obvious why people plant invasives in their gardens. This Japanese barberry, Berberis thunbergii, has been providing an unusually brilliant splash of fall color for many weeks now and it's still looking when most of the rest of the fall color is gone..

Genuinely fiery, the plants scattered about the woods seem to vary in precisely the tone of yellow, orange, gold or scarlet they adopt and there are strings of scarlet berries too. The Japanese barberry is delightful, but it’s a menace.

However. I have to say that without the deer eating just about everything else in the woods but ignoring the Japanese barberry it’s as much the fault of the deer as that of the naturally self seeding barberry.

Because the barberry is such an important garden plant, efforts are under way to develop sterile forms which won’t spread from our gardens into the woods. Researchers at the University of Connecticut, in a limited study, found that seed production of f. atropurpurea was 32 times that of ‘Aurea’ and ‘Crimson Pygmy’ – partly, presumably, because the plants grew much larger. And all those tested produced at least some plain green-leaved seedlings. There’s more here.

Interestingly, the gardener looking after the Royal Horticultural Society's current trial of 70 different Berberis thunbergii reports hardly a single self sown seedling has appeared since the trial began in 2005 - and she doesn't use any weedkiller on the trial.

Now, the University of Connecticut’s researchers are working on developing sterile triploid barberries (with three instead of the usual two sets of chromosomes) and also using genetic engineering to add a gene for sterility into barberries. There’s more here.

Of those around at the moment, B. thunbergii ‘Sunsation’ is said to be completely sterile, and B. x mentorensis (a cross between B. thunbergii and B. julianae) is said to be almost completely sterile. The work at the University of Connecticut looks more promising.