Gardeners’ queries

Press, 11 February 1983, Page 12

Gardeners’ queries

GARDENING

by

M.Lusty

Enclosed are some leaves from Euro x and Super x. growing in a home glasshouse. The disfiguration first appeared around the second truss stage. The plants are now about 2m high, some have grown out of it, and in spite of all, continue to crop well. Conversely a few have died which could possibly be for other reasons. Any thoughts you have on the causes would be appreciated. “X” (Chch). This query cannot be answered with any great assurance because other factors must be examined and considered before a meaningful diagnosis can be made. Leaf yellowing such as displayed on the samples may be due to a magnesium deficiency which is not at all uncommon to tomatoes grown consistently in the same soil under glass. The problem could also have arisen through stress caused by dryness, cold, etc; through the action of a root disease or vascular pathogen. These options would have to be considered in association with further plant examination before a diagnosis can be made.

I should be grateful for advice on an espalier apple tree which began producing fruit three years ago. The first season there were three apples, the following one about 20, but this year there were only a couple of flower clusters in the spring. During the winter I noticed that the incipient buds had been eaten away. I remember that this sort of thing can happen with raspberry canes, but I wasn’t aware that it could occur with apples. Could you please inform me what spray to use and when to apply it? "Apple lover” (Chch).

The raspberry bud moth larvae restrict their activities to the brambles. There is no awareness of any similar bud-devour-ing creature on apple trees, although the presence of woolly aphids and scale insects in large numbers will cause the death of both fruit and wood buds. Without seeing the affected shoots it

is only possible to guess what the trouble may be. Powdery mildew. a fungus disease which has been quite prevalent on other than well sprayed apple trees, is suspected. During the season, regular spraying with triforine is recommended while lime sulphur could be applied as a preleaf fall spray and again at bud movement. Badly diseased shoots should be cut back to healthy growth.

I should be grateful if you could supply me with the names of palms which will grow outside in Christchurch. S.D. (Chch). There is not a great demand for palms for the garden, and so there is really little available. Amongst the hardier ones which are fairly readily obtainable locally are Phoenix canariensis (Canary palm). Washingtonia species’ (Cotton palm). Chamaero humulis (European fan palm). Rhapalostylis sapida (Nikau palm), and Trachycarpus fortune! (Fan palm).

I have a large-flowered clematis, growing on a wire archway, which in its second year has been most disappointing again. I cut it down to about twelve inches last season and it sent out a number of lovely green shoots but these started to turn brown as soon as it reached the top, although they are flowering. The roots are covered with stones and rocks to provide coolness. Is there anything that I can do to make the plant more attractive? L.M. (Chch). Again we have a query which is not easy to answer without a sample and so it is only possible to provide some suggestions of causes and control. There are various rust fungi which will cause distinct browning of stems and foliage. These are not uncommon and can be controlled by spraying with zineb or triforine; the application needs to be repeated at least once oh twice. Many clematis are averse to exposed situations, particularly when conditions remain very warm and dry. wood drainage and a cool moist root run also is preferred by these plants.

I should be very grateful if you could advise me as to the problem with my fuchsias. Some of the leaves from affected plants are enclosed, many of them getting this discolouration

and some have even withered at the tips. S.P. (Chch). This blotching of the foliage of fuchsias is considered to be of physiological origin and currently attributable to faulty cultural'conditions. The withering of the leaf tips is likely to be similarly associated, quite possible sun . scalding due to the presence of moisture on the leaf. The plants may be growing in rather poor soil in too warm a situation.

We have a thirty-year-old lawn in a pretty dry situation. The lawn is mostly tough, droughtresistant grasses, sub clover and brown top. It was sacrificed and top dressed last year with reasonable growth in the spring. The problem is a fairy ring which appears every year. We have tried fungicides, lime, just about everything including close mowing but it still persists. 8.8. (Amberley).

Fairy rings are the consequence of fungal development and spread, and as such require considerable thoroughness to remove. The area to be treated should exceed the visibly infected zone by at least 0.25 m. The turf should be skimmed off and disposed of. A formalin drench should then be applied, the ground lightly watered and then sealed with a polythene sheet. This should be left in place for at least two weeks following which it is vital to thoroughly aerate the soil prior to resowing it. An alternate method is to break the soil up to a fine tilth, spread the recommended dosage of dazomet granules, rake it over lightly, moisten lightly and again seal and leave. Thorough aeration prior to resowing is also again essential.

Could you please identify this bug for me? It was on my runner beans. A.K. (Chch).

The insect in question is a lady bird, a most useful predator to have in the garden. This particular species feeds on European mites.

Gardeners' queries should be addressed to Mr M. Lusty, 32 Brockworth Place. Questions can only be answered in this column. Samples should be carefully wrapped.