Gardeners’ queries

Press, 13 June 1986, Page 15

Gardeners’ queries

along the stalk of the berry; this spot increases in size and finally girdles the stalk, cutting the nutrient supply to the berry, which fails to ripen. Black varieties fail to ripen and remain red and sour, as Indicated in this example. Shanking is associated with conditions of malnutrition which prevent the roots from functioning normally. Sour or waterlogged soils are conducive to the onset of shanking, which can also be brought on by deep root penetration into cold subsoil. Over cropping in any one season or neglect of summer pruning can lead to this trouble due to insufficient soil nutrients. It requires a little investigation into prevailing conditions to remedy this problem.

Could you tell me the name of the tree from which I have enclosed sample? The fruit looks something like a lychee. G.A.(Chch). The fruit and leaves belong to the tree Dendrobenthamia capitata, formerly known as Cornus capitata, and not uncommonly referred to as Himalayan strawberry tree. This is a very hardy and attractive tree with its quite large . sulphurous white flowers amid greyish-green leaves followed by equally conspicuous, edible, dull red

strawberry-like fruit. It is occasionally confused with Dendrobenthamia kousa (Cornus kousa), another of the dogwoods to have been placed into a separate genus.

For the last two years I have had problems with the quality of my grapes. It appears to be some sort of fungus which affects the leaves and grapes, despite treating it with sulphate of lime. One thing which does come to mind: I never had this problem until I installed a Kent log fire and wonder if the smoke from this fire could in some way be causing my problem. Samples ol leaf and grape enclosed are typical. J.W.(N. Canterbury)

Various factors affect the onset of disease in plants, just as they do in all living things. In this case, powdery mildew, a common complaint of grapes, has been severe enough to split the fruit as well as affect the leaves. This can become a persistent problem unless controlled. A clean-up spray of lime sulphur should be followed by a similar one prior to bud

movement. During the year four to six dustings with sulphur are recommended: at bud break; when the shoots are 100-150 mm long, and twice this length; at blossoming; and about three to four weeks after fruit set. Wettable sulphur can be used instead but thorough coverage is essential. The fumes from the log burner would not be contributory to the incidence of powdery mildew.

We have enjoyed your answers to garden queries for some years now. However, we have had difficulty with getting some of the chemicals referred to, in particular the ones recently listed to kill hydrocotyle. As I have tried several places and not yet found them I would be pleased if you could advise the supplier of the following: 1. Bromacil, 2. Bromoxynil / loxynil / Meco crop, 3. Picloram/2,4-D, J.M.(Chch). The inability to obtain some of the chemicals referred to is regretted. The names given are those of the active ingredient(s) and not

trade names by which herbicides, insecticides, and fungicides are sold and most generally known by. The reason for doing so is that this is the most direct way, thus obviating the problems associated with checking out a variety of proprietary products containing the same or varying active ingredients, etc. Similarly, the percentage active ingredient may vary between different brands hence application rates are usually not given. The three herbicidal preparations mentioned were stated as being only available in comparatively large quantities — 51 litres is the smallest container size, as far as is known — and as such can be obtained from stock and station agencies, producer co-operatives, and the like. Perhaps readers could share a container with friends or relatives having the same garden problems.

Gardeners’ Queries should be sent directly to Mr Mike 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-plume can be used for publication.