Diseases & pests

Diseases and pests

Although we may generally say that Hydrangeas are not susceptible to diseases, we can of course not totally exclude an affect. Amply manured Hydrangeas, that grow luxuriantly and have soft flowers and leaves, are a more inviting target for diseases and pests than plants that are kept poor.

Insects like aphids disturb the growing of the plant and therefore the development of leaves and flowers. Combating these in a way that is friendly for the environment is possible, with a mixture of water, soap and spirits. There are also biodegradable remedies available on the market. Ask your expert dealer for these.

Little light green or yellow spots on the leaves and fine cobweb on the underside of the leaf point to the presence of spider mite. Avoid an extensive affect by regularly studying of the underside of the leaves (perhaps with a magnifying-glass) and treating in a timely manner.

A very annoying insect has turned up more often the last few years in Europe; the so called ’Hydrangea scale’ (Pulvinaria hydrangeae). This is a scale insect that makes a kind of a cocoon around itself (in fact they are egg masses) that looks like a wooly spinning from about one centimeter long (½"), half a centimeter broad and a few millimeters high. It is spread by birds. It can also infest Ilex, Acer, Prunus and Viburnum species. A good remedy is not available.

The only remedy is to remove all plants that are affected. So watch carefully, especially in early summer when stems and foliage become covered in those white, oval, waxy egg masses. Action has to be taken as soon as the first affect has been noticed.

Mildew (white spots of mould on the leaves and the flowers) is sometimes seen in Hydrangeas until the autumn. Should this happen, then the best thing you can do is to ask your expert dealer who can inform you about (environment friendly) remedies. If mildew appears in September or later, this will not harm the plant. In autumn no remedy has to be applied, because mildew will mostly not appear again in spring.

By not wetting leaves and flowers at every watering, mildew has less chance to affect your Hydrangeas.

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