Gardeners’ queries

Press, 13 April 1984, Page 18

Gardeners’ queries

Berzelia lanuginosa is an interesting South African shrub which can be mistaken for a conifer. It produces creamy to yellowish white ball-like flowers in late spring; these are long lasting. Growth habit is somewhat lax and narrow, to about two metres in height. It needs good drainage, average soil, shelter from other than light frost, and preferably a position in full sun. The shrub responds to pruning immediately after flowering.

The accompanying weed has gained an extensive penetration into my lawns and, more latterly, is getting into both flower and vegetable gardens. I had minor success in treating it with a strong solution of urea, but this burnt off only the surface and the pest grew*

stronger than ever. Can yon name it please? And can yon suggest a cure? I cannot use proprietary lines like Lawnmaster as I have two massive outdoor grapevines which would surely succumb to the treatment. C.C. (Christchurch.)

GARDENING

by

M.Lusty

A similar query was received and answered recently. The plant in question is hydrocotyle a weed which has become very wide spread and prevalent While there is no real problem in controlling it in areas other than lawns superficial results are general with most forms of treatment available for home garden use. Application of hormones through a lawn boy is of low volume large droplet and its personal careful use in the vicinity of susceptible crops has so far not had any adverse affects on them. The suggestion was made to try the combination of mecorcop and MCPA at one and a half times the recommended strength. Warning: Use of chemical for control of hydrocotol should be used on the lawn with caution because it can damage brown top grasses. My query is what trees would you recommend planting on the West Coast that have the following features: evergreen, at least 2m in height and fast-growing? Would you also include any fruit that grow well in coastal areas? BA. (West Coast).

are all sorts of possibilities apart from choosing plants particularly suited to high rainfall. This consideration apfilies equally to fruit trees, and ocal experience should provide the best guide as to what will do well in your situation. Enclosed please find samples from a Gingko biloba tree with lichen infested branches. This Infestation seems to have affected the vigour of the tree, the leaves are small and sparse, and the growth rate is stunted. How may I eradicate the lichen—do I scrape it off the branches or would a chemical spray be sufficient? E.L. (Rangiora).

Personal experience has suggested that the gingko does not thrive in heavy soils which are inclined to suffer from both drying out and sogginess. The development of moss and lichens is often a very good indication of ill thrift, which is clearly obvious on the samples in this case. Another aspect to look into is to check whether the tree is root-bound a not uncommon occurrence with large specimens when planted without prior examination to see if the roots need to be teased out a bit first. Lime sulphur applied in the winter should control the extraneous growth. However, the best move may be to either find another location for the tree and/or to improve the soil conditions. Please find enclosed a type of worm with which we are having problems in our garden. We would like to know how to eradicate it. I.L. (Christchurch).

This query is so broad that considerable space could be taken to answer it fully, which regrettably is not possible. Consideration could be given to species and especially forms of lophomyrtus; Pittosporums; Aucubas; loquat; Coprosmas; Carpodetus serratus; Pseudowintera; Myrsine; Myoporum laetum; and M. serratum. If the drainage is good then there

The worm to which you relate is a millipede which can be a real old pest and difficult

to eradicate into the bargain. The old method of burying a tin full of potato peelings is still as good a trap as any. Lindane sprinkled over the soil is another method and the application of lime is yet another deterrent. Millipedes favour dampness and soils which contain rotting vegetation; they dislike surface soil which is cultivated frequently.

I have heard that certain foliage is unsuitable for composting. Can you please comment on this? Grape leaves, walnut, and horse chestnut leaves have all been mentioned as having some toxic residue which can be harmful to any plants growing beneath such trees. Does this toxicity adversely affect any compost they may become part of, even if only a small part of the total composition? N.W. (Chch).

potatoes nave enormous noies eaten in them. AM (Rangiora).

Wood lice can be trapped by leaving upturned pots partly filled with wood shavings or some other loose matter about the ground. They can be killed by pouring boiling water over them, and another method involves the spreading of poison bait about the place. This can be made up from 115 g Paris green, 150 ml molasses and 1.51 water. Mix the Paris green and bran dry, dissolve the molasses in the water, and add the dry mixture. Mix thoroughly and apply to areas of infestation.

Enclosed are some samples from a young walnut tree. Could you give me a treatment for the two different sorts of problem. I noticed that some nut clusters had little whitish webs in between the green nuts. The tree generally looks healthy although two branches died daring the summer. I am concerned because a neighbour’s very large walnut tree has looked very sick all summer with most of the top-most branches quite bare and dead looking. D.R. (Chch).

Walnut leaves tend to exude a slime which inhibits the passage of air through the compost heap and for this reason recommendations are to compost them separately. It has been found that where the leaves are not consigned to the compost heap in thick layers but lightly mixed with other material no problems have been encountered; this finding related only to personal experience. There is no problem associated with either grapes or chestnut leaves as far as I am aware.

Could you please advise how to rid the vegetable garden of wood lice without destroying the worms? The wood lice seem to have invaded only since digging straw into the soil. When we turn over a spade full of soil, it just moves on its own so great are the number. Consequently, our

The small protuberances on the leaves of the walnut have , been caused by the walnut erineum mite, an insect pest usually considered to be sufficiently insignificant to warrant control. The other damage to the husk suggests that codling moth is responsible and spray- ' ing with acephate will give > control if it is possible to get adequate spray coverage over the tree. There is a disease which has attacked local walnut trees in the past few years but inspection is the only way that any diagnosis can be ■> made of the trouble.