Plant Doctor Archive

 I HAVE a white clematis climber that is being killed. The main stems are dying — they are getting covered with long lines of brown, small, saw teeth like disease. This same problem also killed my kaka beak.

 IS the damage on your clematis in a herringbone pattern? This is caused by female cicadas laying eggs in stems and branches. The eggs hatch into nymphs and drop to the ground where they live in the soil until conditions are favourable to hatch into adults. Damage can become so severe that shoots become weakened and break off or die back.

It is hard to control cicadas chemically, but you can encourage birds to your garden as they feed on adult cicadas and some soil-living beetles feed on the nymph.

Some plants are more attractive to female cicadas — your kaka beak is one. Avoid replanting these plants; look at alternatives.

Cut back the dead growth and your clematis will come away in spring.

Clematis enjoy a cool, moist root run and their heads in the sun. There are several things that can be done to optimise growing conditions. Mulch around your clematis in spring and autumn, or place a large rock or rocks around the base of the plant to help retain soil moisture and insulate the roots from summer heat.

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• Content or advice may be out-of-date.