GARDENERS’ QUERIES

Press, Volume CXIV, Issue 33650, 27 September 1974, Page 15

GARDENERS’ QUERIES

This veronica, is it hulkiana?, is spoilt nearly every spring by this blackening of the tips, flower buds and leaves, also the oleander’s flower buds do not develop likewise. They have been been sprayed with bordeaux and menazon to no effect. What would you suggest? -. Both are growing in Akaroa. Woolly aphis: our apple trees we spray regularly, but cannot buy lindane anywhere, what else can we use effectively? We have also brushed the insects and knobbly : branches with methylated spirits. I Could you, too, give the recipe; for a "complete fertiliser,” for the orchard and flower garden, and ounces or pounds for 20-year-old fruit trees, or square yards in the garden? We have just been putting on yearly spring applications of fowl manure, covered with fine seaweed or peastraw, citrus trees as well. The passion fruit vine leaves are yellow green, instead of dark green.—iAkaroa). Maldison, menazon and white oil are effective in-season alternative controls for wool aphids. Distorted shoots which display such protrusions as pink swelling can only be eliminated by cutting off the affected portion. The hebe, which is indeed H. hulkeana, is suffering from a complaint to which it is unfortunately rather susceptible to. Timely applications of captan give some control. It is difficult, if not Impractical, to be specific in recommendations for general fertiliser applications for the garden as there are so many factors involved. Soil fertility is most certainly desirable and this can be done predominantly by adding organic matter, preferably decomposed, on an annual basis. Although animat manures are beneficial to soil and plant alike their nutrient release is slow and their use can be overdone. Generally, plants grown for their productive capacity benefit from supplementation of fertilisers which are more readily available to them. A rule of thumb regarding feeding of fruit trees is to apply 0.45 kg (lib) of balanced fertiliser for every year of a tree's age to a maximum of 4.5 kg (101 b Reading your comments to readers’ queries makes me feel a little like Jerome K. Jerome’s leading character in "Three men in a boat.” I think my plants show all the symptoms of disease and pest attack as your readers’ plants. Some specific problems are, firstly; something has attacked our lemon tree and grapefruit. We have sprayed with bordeaux. The manderine tree doesn’t seem to have got this disease but tends to suddenly drop a lot of its leaves. It is only one year old and grows in a pot. The passion vine grows quite vigorously- but its leaves were turning yellow, dying and falling off. There has not been so much of this during the winter but it has several affected leaves still. — M.A. (Chch).

The leaves of your citrus trees give every Indication of suffering from a need of nutrients. It is suggested that they be given an immediate application of complete fertiliser, comprising ammonium sulphate, superphosphate and potassium sulphate (or muriate) in the proportions of 5:4:1 by weight which should be given at the rate of 0.45 kg (lib) for every year of the trees' ages to a maximum of 4.54 kg (101 b The application should be split up, two-thirds of the quantity given in late August and the balance in late November/ early December. Evidence of leaf roller caterpillar, noticed on the leaves, should also be attended to by spraying with D.D.D. or carbaryl. The failure to hold leaves by the mandarine could be due to over or under watering. The passion vine does not appear to be healthy either, but apart from the probability of need for feeding, the exact cause of leaf drop Is not apparent from the leaf sample examined. These plants are shallow rooted and liable to damage from too deep or close cultivation; they are also likely to suffer if the soil becomes very dry and a good mulch Is always beneficial where these plants are growing In an exposed position or very light soil.

Not being able to procure D.D.T. or lindane for protection of my miniature narcissi from narcissi fly, could you please advise me what would be a suitable substitute to dust around the clumps please.—B.W. (Diamond Harbour). Treatment for "dormant" bulbs is hot water Immersion, 43.3degC for one hour. Paradi crystal fumigation is an alter-

native. After flowering, Agrocide should be dusted between the plants and worked into the soil.

Could you please give me some information about Poinsettias? I have one I pruned late summer, and put in the dark for a week or so, but it is still green. How do you keep them red, please? Also, when is the correct time to cut them back? —“Pot Plant” (Chch).

1 Poinsettias are not easy to ' maintain under average houseI hold conditions once they have finished flowering. The flowers are the almost overlooked berry-like developments on the tips of the shoots; the vivid colouration is displayed by the bracts which occur simultaneously. These plants should be given warmth, light, moisture and reasonable humidity whilst in flower. Once the bracts fade water should be gradually cut back before pruning. Commercial growers can adequately time the period of flowering by inducing flower bud initiation from a predetermined date and then controlling the amount of light and particularly total darkness (minimum 12 hours absolute). This is coupled with temperature control, moisture and humidity regulation; all of which are really beyond the possible provisions that can be implemented in most homes. Will you kindly advise me the best way to kill the moss in my

lawns? Last week-end was the first opportunity I had to cut them for some time and I was amazed at the amount of moss present. Would you also tell me whether I should wait until we get some fine weather and the lawns dry out before I start treatment?—M.O. (Papanui).

Moss control of lawns can be carried out when the grass is wet if using the chemical moss killer, sodium pentachlorophenol. Alternatively, lawn sand comprising one part sulphate of iron to 20 narts sand, or 28.35 g sulphate of iron in 90.92 litres water (loz ; 20gals) can be applied under dry conditions.

Enclosed is a leaf off my broadbeans. Could you advise me what is wrong and can they be saved? I have been spraying with Pyrox for the last month. The leaves are only affected on the bottom so far: they are flowering and 12in high. — A.B. iChch).

The disease attacking your beans is known as chocolate spot. This can cause death of plants and favours rain, warmth and humidity for development and spread, but is checked by dry weather. It can be carried over from season to season on infected plant residues which should therefore be gathered up and burnt. Spray with thiram every two to three weeks. Pyrox is an insecticide.