Gardeners’ queries

Press, 12 July 1985, Page 9

Gardeners’ queries

GARDENING

by

M. Lusty

1 have grown a rose from root stock, and a rose from an ordinary cutting. Both flourished. Last year I tried several more cuttings, one of which grew. I’m sure that it had one coloured flower and the remainder are the same as the specimen enclosed. The cutting may have been dipped in a hormone rooting powder. Would you comment, please? H.M. (Darfield).

The flowers present on the rose stem could best be described as freaks caused by some unknown factor in their development. They resemble somewhat a fairly well know form of this type known as Rosa chinensis viridiflora, a “green” rose. It would be interesting to know both the origin of the cutting and

whether the plant persists in producing variations. There is no need to use a rooting hormone to induce rooting, as given a friable medium and suitable cutting material a high percentage strike should be obtainable. Callousing can be achieved by placing the cuttings in moist sawdust.

We have a plum tree, Sage’s Acverna, which has been here for nine years. Bought as an “all-purpose plum, bearing enormous crops of blood red plums of large size and excellent quality, ripening in February.” It has grown into a large tree in spite of heavy annual pruning and although it has blossomed profusely for the last five years it has never produced more than about a dozen plums each season. Could you advise how to get it into full bearing? B.P. (Chch).

The plum referred to is most likely Mac Verna, thought to be a New Zealand seedling of a Japanese plum. This is regarded as being self fertile, but there appears to be a problem in setting in this case. The plums Santa Rosa and Wilson’s Early are more universal donors than most others, and it is suggested that one or other, or even both, could be grafted on to the existing tree. They are both very desirable fruits. Most plum trees on currently available stock tend to make quite sizeable trees, and this growth habit is generally stimulated unless pruning is carefully regulated.

My large walnut tree was laden with nuts this year, but a large proportion of them were badly affected with some sort of blight. The nuts just went black on the tree and withered away, mostly just staying on the branches. Recently too, a couple of large branches were cut and the cuts have not stopped losing sap since. Could you give some advice on both matters? J.F. (Chch).

It is suspected that the problem involved is walnut blight, a fairly common bacterial

The planting of cherry trees has always been fraught with problems, which has made them one of the less easy fruits to grow. However, the demand for them is always very keen if nol competitive, for birds have shown as much, if not more, desire for the ripening fruit. This has meant that trees have to be given secure protection to keep the birds away. A major undertaking for the commercial grower, this is just as meaningful to the grower of but one or two trees. The need for selective cross pollinators for some of the most sought after varieties has been a stumbling block to cropping

disease which may attack flowers and fruit at any time after they first appear. Leaves and young shoots are also susceptible to this disease. Control is difficult in large trees, but should consist of a copper-based spray application just before the flowers appear and thereafter following rainy periods. There is only a short period during which walnuts can be cut back without “bleeding.” This usually occurs approximately between March and early June. I do not know of an effective remedy to stop walnut trees from bleeding.

We want to remove a healthy growth of ivy on our painted summerhill stone house. Could you please advise us of ‘She best way to do it? Ivyfield's (Chch).

of many garden plantings. Lack of suitable dwarfing stock has also meant that, trees eventually reached considerable height. Susceptibility to splitting of ripening cherries following rain has resulted in considerable loss to many commercial growers over the years. On the bright side, there is now available a dwarfing root stock, and at least two, selffertile varieties in Stella and Tangshe. Florence, White Heart, Black Tartarian and Purple Guigne are now regarded as virtually universal pollinators. It is possible to buy multiple grafted trees, or to carry out this task oneself.

At present the only fully effective way of removing ivy is by hand. It can be severed at ground level and allowed to wither, although this may take time. Alternatively it is a matter of pulling it off the wall without waiting — sometimes it can be peeled off in quite large amounts if a good hold can be obtained on a strong growth. Gardeners' Queries, which can only be answered in this column, should be sent directly to Mr M. 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.