Gardeners’ queries

Press, 22 January 1982, Page 11

Gardeners’ queries

Enclosed are leaves from two of my apple trees which seem to by dying. The leaves have been gradually turning brown and many have fallen. I have sprayed with captan, and also carbaryl, and wonder whether this could have caused the trouble with ail the hot weater we’ve been having recentlv. R.W. (Chch) Prevailing dry conditions have favoured the heavy infestation of apple trees by mites where no spraying has been done; some cultivars are more susceptible to those sap-sucking insects than others. The discolouration of the leaves is typical of the effects of these pests. Tetradifon and/or all-seasons oil should be applied as soon as possible. Captan is a fungicide for control of some fungus diseases, and carbaryl is an insecticide which will only control chewing insects.

I have a hoya plant which I think is the one called “Bella.” It is growing like mad, making a lot of good leaves, but although I have now had it for five years it has never flowered. It gets plenty of water, is in a sunny position, has good soil and is given the occasional liquid feed. How do I get it to flower? “Disappointed” (Kaikoura). The plant to which you are referring is most likely Hoya Bella. It has been quite noticeable that those hoyas which flower well tend to be the less robust, almost sickly looking plants, rather pale in leaf colour. They seem to do best if confined to a smaller pot than would appear necessary and should not be fed too much. Although these plants should be given ample light they should not be in full sun. Water periodically but do not keep moist.

Enclosed is a bunch of grapes for your inspection and advice. The brown rotting appearance of about one quarter of my crop has me wondering whether it is sunburn or some kind of disease. I haven't sprayed them at all. H.W. (Chch).

The symptoms displayed by these grapes suggest scalding rather than disease. This could have been brought about by excessive defoliation which has exposed the fruit to the sun. Such damage is worsened if there is moisture on the surface of the berries. There is no remedy at this stage but further losses could be avoided by providing some light shading on very hot sunny days. As an added safeguard spraying with acephate is worth while.

Please could you identify this peculiar plant which is growing in a friend’s garden, and at the same time could you identify this other one which I have had growing for several years in my own place. There are others which have different coloured flowers. How are these plants grown — from cuttings or would vou have to wait for the seed? D.P. (Chch). The peculiar plant to which this query refers is Bupleurum rotundifolium. Hare’s ear. It attracts attention because of its perfoliate leaves and to i a much lesser extent the umbels of tiny yellow flowers. It is an annual, regarded as a weed, and could be grown from seed. The other plant is a perennial. Mirabilis jalapa. Marvel of Peru, also known as Four-o’clock plant because of the tendency of the flowers to open in the afternoon. This ornamental has five lobed tubular flowers, red, yellow, white, even striped and mottled; it. too. can be raised from seed.