GARDENERS’ QUERIES

Press, Volume CXI, Issue 32774, 26 November 1971, Page 11

GARDENERS’ QUERIES

Could you please name the enclosed flower? It is deep blue with bright red stamens when first out. I would also like to know something about it— M. D. (Greymouth).

The plant is a species of echium, some of which can grow at least ten feet tall and are quite spectacular. Others are regarded as a weed.

“PEACHES” (North Canterbury).—Samples were too dried up to be of use in diagnosing trouble. Perhaps you would care to send some more together with a twig or two.

I wonder if you can help me over the enclosed leaves of a standard bay tree? It has a scale for which I have been spraying but I have not killed it yet I have a pair (which took me years to find) in concrete tubs—ll inches square by 9 inches deep. I have potted it into compost and potting mixture but no improvement— A. W. (Christchurch).

Queries are answered only through “The Press.” The tubs would appear to be too small for these plants making them root bound. Another likelihood is that the soil also becomes exhausted. Scale are still evident. Bay Laurels certainly are not generally available, if at all. Enclosed are the top leaves of my six-year-old rhododendron. The tree is planted in good welldrained soil enriched annually with leaf and animal compost. I have a drum placed around it for shade until neighbouring trees grow up and the plant is watered two or three times a week in summer with fortnightly dressings of liquid manure during the growing season. It was transplanted

from a soil of too high an acid content yet it appears to suffer from stunted growth, little or none in the last 3 years, and leaves tend to be. yellow and in tight clusters. “CURIOUS” (Hawarden).

Insufficient leaves were sent for examination. However, the details which you have given suggest that conditions are not suitable for rhododendron growth. They resent deep planting and do best in a cool, moist root run, of acid soil, with protection against strong wind and direct sun, at least until they are fully established. It is most important to ensure that the root ball is thoroughly moist and not hard when planting. There should be no need to apply all the different liquid feeds which you are giving. An annual side dressing of blood and bone or complete fertiliser (1:2:1) should generally be enough. The drum may be excluding too much light. Could you please tell me if there is any weedkiller that will deal with the enclosed piece of a plant called something like acerlaria? I have tried paraquat and other hormone weedkillers without success as it does not seem to get down to the horrible bulbs the plant grows from. Also is there any cure for dandelions and could you tell me the quantities of sulphate of iron required to turn fresh sawdust a dark brown before using it as a mulch on my rose beds?—“FENDALTON” (Christchurch).

Dandelions can be killed by applying mecocrop, MCPA, 2, 4-D or a combination of the first two. Blood and bone or sulphate of ammonia are the most usual fertilisers applied to break down fresh sawdust but this is not a rapid process. Half

a pound of sulphate of ammonia per square yard may be sufficient and it should be applied to thoroughly wet sawdust. Identification or recognition of the name of the weed was not possible. Repeated applications of oil esters of 2, 4-D will kill many bulbous plants.

I would like the enclosed specimen identified, if possible; also can you give me any idea just how long grass is removed after being sprayed with weedkiller? Mimosa (Rolleston). I am unable to identify the plant from the specimen sent. Samples for identification must be fully representative, preferably several in number and properly wrapped particularly during warm weather. It is not clear what is meant by the second part of your query. Removal is dependent on the type of weedkiller used. Grass killed by a desiccant such as paraquat can be cleared off within several days after spraying. The use of such as amitrole T or dalapon requires several weeks before becoming fully effective. My Japanese maple, a very young one, is just inside a low fence. It was a picture until it suddenly became very patchy looking. Could you advise what I should do?—“Disappointed” (Christchurch). This variety of Acer palmatum atropurpureum will not tolerate exposure and is best planted in a sheltered spot. When in an open position subjected to winds the leaves are liable to get torn and frayed and withering of the edges is also likely, particularly in young plants.