Gardeners’ queries

Press, 24 July 1987, Page 14

Gardeners’ queries

Could you tell me what is wrong with the tree from which the enclosed cuttings have been taken? Three years ago this tree was looking very healthy, but since then it has appeared very jaded. C.B. (Greymouth). The corky protuberances prominent on the wood are natural developments which form on the branches of Liquidambar styraciflua as they mature. The similar formation is to be found on the English elm, and is nothing to be concerned about.

In the past few weeks it has been quite noticeable that nearly all the carrots taken from our garden have been pitted, similar to the enclosed. This has not occurred before. The crop has received no different treatment from the usual and has not been sprayed or supplemented at any stage. Could you please comment on the matter? C.P. (Chch).

The tunnelling evident on the enclosed carrot has been caused by the larva of the carrot rust fly. This pest is widespread, certainly in the Christchurch area, and could almost be said to be as prevalent on carrot crops as codling moth grubs are in apples where these crops remain unprotected. Parsnips and celery are also susceptible but to a much lessor degree so far it seeriis. Control consists of applying diazinon to the soil before planting, followed by a side band treatment 10 weeks after

seed sowing. Excessive loosening of the soil should be avoided, arid in the process of any cultivation or weed control, care should be taken to avoid exposing the tops of the roots. Foliage from lifted carrots should not be left around but buried or well covered over if consigned to the compost heap. Garlic and onions are suitable companion plants which may act as deterrents to the fly. Our garden is situated a few hundred yards from the sea, which is perhaps why lichens are quite a problem. I believe that lime sulphur will eradicate it, but wonder whether it could safely be applied to azaleas. M.M. (R.D. Parnassus). Lime sulphur can be Used for the control of moss and lichens, but only on deciduous plants with but one exception, apricots. It is doubtful whether there is a connection between the development of lichens on your plants and the proximity of the property to the sea.

I wonder if you could identify the plant in the enclosed photograph? It just appeared In the garden, grew quickly, and when its buds open the flowers stay for about 10 days; they are like beautiful blue satin butterflies. The foliage is dark and narrow, with thorns about an inch apart. M.L. (Chch). The plant depicted in the photographs is Puya alpestris, a bromeliad and one of the

hardiest of the genus. This spectacular flowering plant, which is of Chilean origin, always draws attention to its beautifully coloured flowers. Although some of the genus die following blooming, this species does not. We have a number of camellias which we have grown from seed and cuttings. Although some of those are now about four years old, they are not yet flowering. Is there any thing we can do to encourage them to do so? We feed them each year with acid fertiliser, and some of the brushes are now a nice size. M.C. (Ashburton). Although the development of flower buds may occur within a year or two of rooting of camellia cuttings, much depends on the species or form as well as the way they are promoted to that stage. For instance, the reticulatas are very much slower to come into bud than are the sasanquas. Seedlings generally take several years to do likewise. Of particular note is to avoid dense shade and over-feeding. Your plants will flower in due

Gardeners’ Queries should be sent directly to Mr Mike Lusty, 56 Wayside Avenue, Christchurch 5. Samples should be separately wrapped in a plastic bag with air holes. Provide representative, good-sized samples, and your name and address. A nom de plume can be used for publication.