GARDENERS’ QUERIES

Press, Issue 32333, 26 June 1970, Page 7

GARDENERS’ QUERIES

I have a purple lilac about 7ft high which is at present covered in buds. I wish to prune it back a bit , and wonder how and when. ’ ' Also I have enclosed a > piece of a plant which came up in the garden [ about two years ago which [ doesn’t appear to be a weed. Home Gardener (Ashburton). As a general rule lilacs do I not need pruning and if the; purpose is to reduce growth; or create a smaller subject the object defeats itself. Light pruning if desirable, such as removing thin spindly twigs or intercrossing branches, should be done immediately after flowering and spent flower heads can be removed at the same time. These should be cut back to immedi tely above a pair of buds. Large overgrown specimens may be rejuvenated by really hard cutting back in the winter months. It normally takes three to four years before flowers can be expected after such treatment. Cut surfaces should be sealed without fail. I cannot identify the plant.

“Raspberry” (North Canterbury).—l do not feel inclined to venture an opinion on the possible cause of the fieath of your raspberries without seeing affected plants, preferably complete with roots.

Could you please inform me of the best way to kill eltn trees and suckers.'Also what type of spray should be used to kill weeds on a driveway.—R.P. (Rakaia). The tree can be cut down and the stump swabbed on the bark can be frilled right round with an axe and the exposed wood immediately beneath it sprayed or painted with chemical. In both methods 2,4 D with or without 2,4,5-T, preferably using diesel oil as a dilutent can be used. Suckers can be sprayed with this mixture. There are several chemicals which can ; be used for total weed control of driveways. One with a very wide spectrum is a combination of grass killer (dalapon), general and broadleaf killer (amitrole) and preemergence agent (simazine) which has quite a long term effect. It is however prefer'able to use a special mixture

of amitrole and dalapon first [if perennial grasses such as twitch are greatly in evidence. Spray according to ' manufacturer’s instructions. I Enclosed leaves from a ; Chinese hollygrape Mahonia ; lomarii folia which I have | growing in a scree garden. [ Small light brown spots appear on several leaflets ( and within a time it is all light brown colour and soon falls off. It is a young plant and appears to be making no headway at all.—R.S. [ (Christchurch). It has not been possible to ; positively identify the trouble [which appears to be a leaf spot fungus, to which they

are susceptible. Pick off any diseased leaves and try Captan for future control. Could you tell me how to eradicate the enclosed weed from my lawn? It spreads into the flower garden but can be kept under . control there. L.B. (Akaroa). The weed is hydrocotyle commonly called pennywort and one which is more common in lawns than is generally thought. It is not readily controlled and repeat applications of 2,4, 5-T or a mixture of MCPA and MCPP in autumn or spring are usually necessary.

Enclosed please find a twig off an orange tree. It is only a young one bearing fruit "for the second

year. What is the blackness ort the leaves?—K.U. (Amberley).

Your orange tree is heavily infested with scales. The black discolouration on the leaves is a fungus growth which has developed on the so-called honey dew secreted by the scales. Trees of any age are susceptible to attack by these insects. Spray with white oil and repeat at least once. Do not spray in very cold conditions and ensure complete coverage of stems and leaves both upper and lower sides.

Is it correct that the Chinese gooseberry or Kiwi berry is a native of New Zealand? L.S. (Culverden).

The name Kiwi berry is a misleading commercial aphorism given to the fruit in an effort to increase sales overseas. It is not a native plant at all but originates from the Yangtse Valley in China. It was introduced into New Zealand about 1906.

I have a healthy Ficus decora which has three stems. Someone has suggested that I cut off the two smaller growths, leaving one main stem. I am quite happy with my plant as it is, but if the correct way for it to be grown is on one stem please advise. —B.D. (Amberley).

Strictly speaking there is no right and wrong way to shape anything. The point is that we make plants conform to a particular form of growth perhaps to achieve a more aesthetic plant or to train it in a particular direction, may be to get more flowers and fruit from it. Whatever the objective there are frequently several ways to achieve the same or similar objective. Rubber trees are almost without exception grown on a single stem and I think a multiple stemmed plant could be both unique and attractive. Thank you for your comments concerning various aspects of this page, particularly concerning this section, where it [is attempted to provide ansIwers which can be of general [interest and help to others [apart from the sender of the iquery.