Gardeners’ Queries

Press, Volume CVII, Issue 31409, 30 June 1967, Page 6

Gardeners’ Queries

(1) Could you please identify the enclosed leaves from a climbing plant bought as a Hoya. Purchased four yean ago, it has attained a length of about 10ft with two leaders and must be completely pot bound as it is in the original container. As yet is has not flowered. Apart from regular watering and a weekly supply of a liquid plant food it has had no attention. Perhaps its position near an electric stove is too warm? Do you consider that such a plant could be successfully grown outside on a north wall where soils tend to dry out frequently. The leaves of the plant are opposite and the plant climbs by twining around a support.

(2) Although most jarden books etc, mention the effect of leaching of lime in areas of heavy rainfall, none I have read give any guidance on the effect of liberal hosing on soluble nutrients. Your comments please. I have

an idea that measurement of overhead irrigation of a home vegetable garden would shew that the rainfall in Christchurch measures nearer 50 inches than 25 inches. If such is the case then heavy applications of lime and fertilisers are indicated.— M.M. (Chch )

The plant in question is a Hoya which will make considerable growth in a few years and does take some time before it flowers. The general method of growing Hoyas is to keep them pot bound as this seems to induce better flowering. Watering, especially of a young plant, in winter should be done thoroughly, but just before the soil has dried out completely. At other times it is essential but drainage must be good. Although an occasional liquid feed is beneficial the weekly treatment you are giving it is excessive and the leaves suggest overfeeding. Hoyas prefer warmth, a temperature between 60deg. and 70deg. being most suitable. I have heard of a plant being grown outdoors here but do not know whether it has flowered. Anyone who applies water to a garden would naturally increase the annual soil Intake of water above that of the annual rainfall figures. The exact amount could be recorded by buying a guage to measure the flow of water from tap to garden, or by rough calculations applied to a formula. Numerous factors are involved in supplying tho optimum type(s) and quantity of fertiliser for a soil or a particular crop as needs and requirements differ so much. The best thing to do when not sure of what to apply, or how much of any particular thing, is to get representative soil examples from say half a dozen places in the garden and have a full soil analysis made. This may indicate additions. It is as well to remember that excess of say lime can cause poor availability of trace elements: but although very acid conditions cause a low availability of calcium, a real deficiency of this element is rare in plants. One can worry unduly about the health, etc., of plants.

I have Golden Delicious, Ballarat and Cox’s Orange which appear to be riddled with • mealy bug-like insect which turns red when pressed and gives a woolly appearance otherwise on the branches—it actually looks like cotton wool. In winter when the “cotton wool” appearance has subsided the affected parts look swollen like the joints of an arthritic patient What is it—-what spray should I use against it?— C.L. (Christchurch).

The insects are woolly aphids for which the control now is winter oil in combination with lindane. The woolly appearance is typical and I must say your description is very fitting. I have a peach tree growing in about eight inches of soil with sand beneath at a holiday cottage on a North Canterbury beach. The peach is very early, ripening by New Year’s Day, always crops well, but about 80 per cent of the fruit splits when on the tree and becomes a home for earwigs. It is most annoying to bring in peaches and then to find earwigs dropping out on to one’s plate. Can you please give reason and remedy for splitting. A.A. (Christchurch). Some varieties of peach are more susceptible to stone splitting than others. Although defective pollination is suggested to be the cause it is more widely considered, to be the result of a calcium l deficiency. I