Gardeners’ queries

Press, 17 January 1986, Page 13

Gardeners’ queries

Enclosed please find samples of black mulberry bought about 12 years ago. The last few years it just comes to this stage, and then the fruit drops off. It gets plenty of water, yet this sample is all it has done in its life. I’m beginning to think that we have been sold a dud. “Mulberry,” (Winchester).

Examination of the leaf samples suggests that the tree in question is not the black mulberry, but the white one, Morus alba. Apart from the probable mistaken identity of the tree, there is usually a natural shedding of imperfect fruit towards the end of December. Morus alba does not generally fruit as heavily as the Black Mulberry, and although its fruit is not as large or as juicy it is still edible; it forms a nice, medium-sized tree.

The small tree from which the samples come may need treatment — is there anything I can do about it? Also, what is the best thing for a persistent “mildew look” on ajuga? J.L., (Chch).

Because of the decomposed state of the leaf samples it has been impossible to identify the problem. Some of the ajugas do develop a “bloom” on the leaves but this has never been considered to be harmful. Without seeing the condition referred to it is not possible to comment further.

The enclosed specimen of kumquat, is growing very well, but the leaves look rather yellow and speckled. It is well watered, and growing in a tub. The new growth looks healthy, but becomes yellow as it gets older. A.N. (Chch). The yellowing of the foliage, accompanied by the speckled appearance, is due to a very heavy infestation of mites which have been quite prevalent on various plants during the recent dry spell. These pests will not remain localised but will spread to the new growth where their sap sucking mode of feeding will induce the same effect on the young leaves as on the older ones. Control is best by applying a miticide such as dicfol or tetradifon to which a few drops of summer or white oil should be added. This treatment should be repeated in about three weeks time. Could you tell me if this is a new kind of aphid, as I have never seen a plant afflicted like this rose bush? The whole of the bush is covered with a sooty black extrusion which has attracted blowflies. As the new growth began to come away healthily I cut the whole bush back as the old foliage remained black. What should be done to treat reinfestation? R.B. (Cheviot). Various insect pests were noted on the rose samples, twoof which could be contributing to W sooty black deposit evident. This so-called honey

dew is released by some scales, and aphids which attract a mould fungus, and also some other insects such as the blowflies. The best remedy in this case is a thorough application of summer, white, or all season’s oil, to which should be added acephate. Do not apply on hot sunny days. It will take a little time before all the mould disappers.

I have a standard rose which is cerise. I took a cutting at pruning time which struck, and in the months after covered a fence. However, the flowers really surprised me by being cream not pink. There is no chance of error for I have no cream roses. What did I do wrong as I thought that cuttings above the graft came true? B.K. (Chch) The vigorous growth mentioned suggests that the cutting was made from the root stock rather than the cultivar, and not the result of mutation or sport. Rootstocks not infrequently develop shoots even on standard forms. It may be worth noting too that roses are budded and not grafted, as a rule.

Gardeners’ queries should be sent directly to Mr N. Lusty, 56 Wayside Avenue, Christchurch 5. Samples should be separately wrapped in a plastic bag with air holes. Provide representative, good-sized samples, and your name and address. A nom-de-pluise can be used for publication.