GARDENERS’ QUERIES

Press, Volume CXI, Issue 32541, 26 February 1971, Page 11

GARDENERS’ QUERIES

Please could you tell me the name of this shrub which has pink flowers?— K. (Linwood). The plant is Spiraea japonica.

I have a climber, Caroline jasmine, which I planted in the spring. It has reached a height of about 30in from the ground and until very recently it grew unmolested, but now something is nipping all the top shoots off. Slug bait and derris dust have been used to no avail. Could you recommend a control? —M. B. (Christchurch).

The correct name for Caroline jessamine is Gelsemium sempervirens (also note the correct spelling of “jasmine” in this case). Most probably caterpillars are responsible for the damage and careful examination of the plant should reveal their presence. Carbaryl or D.D.T. applied as a spray will give control. Slugs are not likely to make their way up the plant and slug bait is only of use against them and snails.

Every year the wasps time their arrival to consume my grapes just when the fruit is at its best. I have tried the suggestion of placing sugary jam at the foot of the vine but they ignore this completely. I would be grateful to know of a remedy.—M.G. (Rangiora). I must acknowledge that apart from finding the wasps’ nest and destroying it I do not know of a really effective means of preventing attacks

by these insects. The sugar bait can be mixed with a suitable poison which would certainly eliminate all those wasps which sampled it Apart from this care should be taken to remove any attractants such as damaged or rotten fruit There may be sane readers who have reliable methods of wasp deterrence or extermination. The area in which we live used to be part of the old Waimak, therefore our garden becomes dry very quickly. Our vegetable garden is not a problem because each year we either plant lupins or dig in manure in the area which is -not carrying a winter crop; but the flower garden is another matter. It is mostly trees and shrubs now and there is little implanted soil where the manure may be dug in. Three years ago I put sheep manure and wool clippings over the ground. The soil has since become very caked and will not break up, even after watering, wittout hard work. I thought of putting sawdust on but remembered reading that one has to be careful with it for some reason. I would appreciate advice on how to improve the quality of the soil, etc., J.T. (Christchurch). Lupins, vetches peas and clover are excellent crops to grow as green manure. Fresh sawdust should be used with care—it is best to stack it and allow it to decompose. If fresh sawdust is to be used, it should be applied only to thoroughly watered

ground with the addition of sulphate of ammonia or blood and bone, rate 4oz per square yard. The reason for caution ih applying fresh sawdust is because it can cause nitrogen starvation amongst plants; which is the reason for adding a nitrogenous fertiliser.

Double digging with the incorporation of rotted compost or other organic matter, such as old pea straw free from chemical weed killers, above the forked over second spit will help to enrich the soil and also make it more moisture retentive.

It is not easy to prescribe quantitive requirements but it is necessary to apply ample such materials in the trench—a few wisps of straw are useless. Surface mulching also is of considerable value but should be done before the onset of dry weather.

It is not possible to transform ground from one state to another overnight; usually it requires following up to maintain it at this new level and sometimes only little change is possible.

Would you please identify this (enclosed) plant for me. Last summer it hdd only the big leaves and did not flower. This year it has flowered and the seed tends to stick (to clothes). It is the only one growing here in the garden and nobody around here seems to have seen it before.—lLJ. (Hinds).

The plant is known at burdock, Arctium lappa and is a biennial which is why it did not flower in its first year. The plant may look attractive with its purplish flower heads set atop 3ft or 4ft stems but the burrs which transplace the flowers attach themselves to anything which brushes past the plant. Personally, recommendations are -o destroy it particularly as this is not a desirable pasture plant. Could you state the reasons why the (enclosed) leaves from an ash, a hazel nut and a cherry tree are the way they are and what can be done to restore them to their former healthy state? “Early Fall” (Ashburton). All are suffering from scorch which could be attributed to wind bum and/or sun burn, most probably accentuated by dryness at the roots. Watering may help a little but at this time of the season leaves of most deciduous plants are already past their best and little if any further growth is likely from now until next spring. Would you please advise on a point in growing pansies. In past years I have bought a number of choice large varieties just flowering but, after planting and in spite of ample watering, the succeeding flowers become smaller and smaller. About once a week I have given them some weak liquid feed but all to no purpose. Before planting I included a little lime in the soil so ' I am stumped as to what I can do next.—H.P. (Christchurch). The first flush of flowers are often the best and this gpes for many other flowering plants, apart from pansies. Many plants are also brought to a particular stage with the special attention which is given to them. Pansies thrive best in a soil wellendowed with humus, moisture and some shade from the mid-day sun. Liquid feeding on a weekly basis is considered helpful to aid growth and promote better flowering but this, I think, can "be overdone. There is no need to add lime for pansies’'unless the soil is particularly acid.