GARDENING HINTS
Let’s talk about the problems with box….
It is now extremely likely that you have seen box that’s looking far from well,
either because of box blight, now widespread, or because of the box
caterpillar (Cydalima perspectalis). I was feeling very pleased because we
seemed to have escaped both, but sadly not. Last summer was the first time
that I could see signs of the caterpillar on our hedge, and two variegated box
balls. Time to take action.
I’ve looked up the life cycle of the moth and during the winter the
caterpillars hibernate deep within the recesses of the bushes (they are very
difficult to spot at the best of times). Depending on the temperature they will
start to pupate in March/April and hatch out into moths, which are nocturnal.
The moths mate and lay eggs which hatch out into voraciously hungry
caterpillars, and so the cycle starts again for at least two, maybe three
generations in a year.
I’m loth to use a chemical spray so I’m trying the pheromone route which
is a three pronged attack. Pheromones in the spring to attract the male moths
so that they don’t mate. Stage 2 is to get a parasitic wasp which will find any
eggs that are laid. Once located, the Box Tree Moth eggs are parasitised
and killed. The eggs then, instead of producing Box Tree Caterpillars, release
new Trichogramma wasps to locate and kill more Box Tree Moth eggs! It is
possible to move to Stage 3 if actual caterpillars are seen- there is a
nematode for them too. Anyway that’s the plan.
Because of this problem with box all the advice is NOT to plant in the
first place, and Garden Centres are usually very helpful about suitable
substitutes. The criteria to think about are that a substitute has to be green,
evergreen and suitable for clipping.
Here are some suggestions from a good article in a March FT by Jane
Owen called ‘Think Outside Box’, rather witty:
Number one:- Japanese Holly (ilex crenata). It looks very like box from a
distance, but can get another disease called black root rot. A better one may
be ilex Maximowicziana Kanehirae! Ilex Max for short (Phew)
Numbers two etc:- euonymous microphyllus, some pittosporum, lonicera
nitida (a shrubby honeysuckle), osmanthus burkwoodii (good for topiary),
phillyrea latifolia (green olive,’tough as old boots’)…. To name but a few.
And, of course, my favourite, yew. Why not forget all these troubles and visit
other gardens such as Rodmarton Manor, or Hidcote to see specimens of
topiary and see how they are coping with the problem. Good luck.
Barbara McNaught