Gardeners’ queries

Press, 18 June 1976, Page 15

Gardeners’ queries

It has been said that Epsom Salts are beneficial in treating leaf curl on peach trees. Could vou confirm this, and if so, details as to quantity and time? Also my lawn is being covered with depressions under the qrass. Is there any remedy for this?—W.B. (Christchurch). The remedial properties of Epsom salts enjoy a wide reputation with many gardeners. Unfortunately almost all these concepts. including the control of leaf curl, are incorrect or based on misconceptions. A major use of magnesium sulphate which is the chemical name for this substance is to correct magnesium deficiencies. Depressions in lawns are generally the result of ground subsidence caused by the settling of till in areas which may not have consolidated as well as surrounding ground, especially along pipe lines and such like, or the decaying of large tree roots or stumps. Ground which has been subjected to very heavy traffic or extremes of weather may also subside in places, depending on circumstances. Depressions of this nature can often be repaired bx gradually filling them in with fine soil. Alternatively the turf can be carefully lifted. soil added to the underlying area and the turf then relaid. During the past two years my Burbank plum has fruited well but a lot went rotten on the tree before they ripened. When the fruit formed it was not all true small fruit but sort of hollow like. I took these off and sprayed with summer/winter oil and later on with carbryl. Can paraquat be sprayed on chick

weed without injuring raspberry canes? Could you tell me what could be used to control suckers in lilac and japonica trees? Also what could be used to destroy the root of an unwanted japonica? My lemon has fruited quite well until last November when it was found that although the ’* lemons were lovely to look at l * they were dry. The tree has v been well fed and watered.— E.J. (Christchurch). d Initial reaction to this query on e rotting plums was “brown rot.” s a disease which was very pre- >- valent on home garden stone nj fruit trees duiing the last iruits ing season. However, a little ; sketch which accompanied the e iquery helped to clarify at least hi the initial symptom. The early • s disease on this plum tree was iJ bladder plum, a fairly common d fungus disease wherever plums ’flare grown. Control consists of a < bud movement spray with i )- Bordeaux mixture followed by -r another one 10 days later: and o the cutting out of infected n shoots in the summer time. Para>f quat can be used with care d around the base of raspberry h cones to control chick weed, but f avoid as much as possible conil tact with the canes. The onlyci way of controlling suckers of most trees and shrubs is to grub them out at source. Apart from idigging out the offending root the application of dicamba plus 2,4-D may give the desired result. Dryness of lemons at the time of the year mentioned is a common and often puzzling occurrence. particularly when apparently -all care has been lavished on the tree. Generally it can be traced to cold weather: - during the initial stages of development. There is really only one remedy, and that is either 1 to relocate the tree- in a warmer ■ position or to provide more ' adequate protection during the j; period of colder weather. Enclosed- cuffings from our chrysanthemums, and could | | you please say if there is any cure for the disease? The plants are only two years old and were quite healthy looking until they came into bloom. The tops have been cut and burnt, but will the new growth be affected? — E.J. (ChristI church).

It would appear that the incidence of chrysanthemum gall nidge is rather more prevalent his year. The raised pimplelike formations on the leaves ate caused by the larvae and give the outward impression of lisease. Burning of the infested growth at this time of the year can be recommended. During the vear the plants should be regularly sprayed with diazinon. My asparagus bed was badly overgrown with clover so paraquat was used on recommendation. This caused the leaves to turn colour but did not stop the growth. Would you please recommend a spray to rid the asparagus bed of clover? At the same time would you tell me of a spray effective against horse radish? — J.W. (Christchurch). Paraquat is a dessicant type herbicide generally effective against weed seedling and most kinds of annuals. It has only a temporary effect on perennials and is therefore usually wasteful on such, certainly on clover control. The combination of ami-trole-T and simazine is suggested for clover control while there are not any spears above ground. In other words this combination is for winter application only and applies similarly to the alternative of dicamba. Horse radish has proved to be a difficult plant to control by any means when well established and the only suggestion in this instance is to apply amitrole-T when the plants are in active growth and to respray the regrowth when about 120 mm high.

I am having difficulty in making permanent labels for our shrubs. I have found that Tin x Tin x Tin wooden pegs with a piece of Venetian blind glued to a slit in the wood are best, but I have not found a permanent marking material. A Chambers marking pencil has lasted the longest but is not permanent. Can you suggest a marking system that is easily read from a distance? — H.S. (Ashburton). The type and form of labelling of plants is really dependent on the purpose. The use of clear \arnish will help to retain lettering which can also be applied with paint to treated wooden or galvanised plate pegs. The use of metallic or plastic tape in conjunction with a lettering applicator is another way of preserving labels indefinitely, but of course such would not be legible from a distance. When seed is sown from annuals such as crackerjack marigolds, dwarf marigolds, asters, etc., do the plants grow true to type or are they changed by the bees? Could you also tell me if there are any books available on this subject? — "Interested Gardener" (Hari Hari).

Hybrid or some specially raised strains of plants do not come true to type. They may revert to the original crosses or show considerable variability depending on circmstances. In some cases where plants are receptive to cross-pollination variation can occur even between different varieties of the same kind. No single book title comes to mind which deals specifically with the information you seek, but the more advanced text books on botany and some of the better gardening publications usually have a chapter devoted to the subject. Ask at your library or bookseller.