SUMMER PRUNING OF FRUIT TREES.

Otago Witness, Issue 2914, 19 January 1910, Page 6

SUMMER PRUNING OF FRUIT TREES.

A considerable amount of attention is now being paid to fruit culture in Otago, and some very tine orchards are to bo seen an various parts of this province. There seems to be no good reason why the fruit industry should not be much more fully developed than it is at present. In connection with the summer cultivation of fruit trees, and summer pruning in particular, some very useful information is supplied by the Victorian Journal of Agriculture from the pen of the principal of the School of Horticulture, Barn,ley. The writer, while dealing fully with soil treatment, spraying, and the general management of the orchard, states that the time for summer pruning of fruit trees is a •consideration that can not be settled by any general rule, as so much depends on the state of the tree, the condition of the soil, the dryness or otherwise of the weather, as well as the situation of the orchard, and these and other considerations must always be taken into account by the operators. From December to February is given as the time that apples and pears may be treated according to the climate and weather conditions, while apricots and peaches need summer pruning much earlier, some operators having laid it down as a rule that nav true requiring

summer pruning may be pruned just before the crop begins to ripen. This may suit some seasons, but not others, and in referring to this question the principal of Barn ley School, Victoria, says that disbudding and pinching back shoots, so as to further strengthen and shape the trees and vines should now be completed, and the work of the summer pruning commenced. “Summer” or “green” pruning is an operation which is not practised in Victoria, and, generally, the existing opinions on this subject are so vague that, even where it is performed, a small amount of an element of uncertainty is always existent in the mind of the opera- | tor. The principle of summer pruning is, ; states the same authority, that the wood j growth is reduced, so as to induce in- ( creases! fruit production for the next sea- | son. The unnecessary wood is removed, and the sap is directed into other chan- - nets, strengthening and building up weak or immature fruit buds. Summer pruning is exceptionally advantageous to young or t to strong growing trees. Whenever a tree has been heavily pruned during the dormant season, a very fair growth of wood will ensue, and this wood is generally | strong. To “stop” or summer-prune this i wood will have a very beneficial effect on the productiveness of the tree. Of course, if the growth is excessive and rank, a judicious selection will need to be re- 1 tained, and the balance disbudded. The result of summer pruning will be that, j wherever the growing shoot or. lateral has been severed, the buds below the cut will receive the full benefit of the sap which previously went to nourish the wood which has been removed. If this operation were performed too early, the bud at the point of severance will merely j push its way out and continue the j growth. Tliis result is undesirable, as the ' very object to bo attained is defeated, the . sap being utilised in the production of new wood, and not in the strengthening and enlarging of the fruit buds. Some- | times even this end is desirable, but it i is only when the lateral has been of an ; excessively strong nature, and an exten- ; sion is desired, though only as a weak growth. Two points to he noted are: 1 First, the terminal ends of main, second- 1 ary, and extension limbs should never be cut at summer pruning: secondly, the cut must always be made where 'a leaf , is existent, so that the sap may be fur- | nished and perfected for the whole of the lateral. If the cut he not made at a ; leaf, the probability is that the tip of the ; lateral will lose its vitality and ultimately ' die, owing to the fact that no foliage exists to draw and perfect sap for its nourishment. A number of problems in fruit production and tree culture are still awaiting solution, and among these is the question as to the value of summer pruning on those trees- which are supposed to be biennial croppers, such as the Rymer apple; or on such trees whose unproductiveness have been charges to the debit account of the stock they are worked upon. It is an accepted fact that unsuitability of stock will result in unproductiveness, but we might pause before we would say that non-production can always be attributed to unsuitable stock. Coe’s golden drop plum, for example, is a tree that will not bear on unsuitable stock; but sometimes trees of this variety have only been a partial success as fruit producers, even when on their supposedly correct stock. In a case like this summer pruning has been known to produce a marked increase of crop. In January of last year they were summer-pruned, with the result that on every tree a very large number of new fruit bnda were formed' on almost every lateral, and the trees set a heavy crop of fruit. At present, the heaviest crop ever known is on the trees. Of course the wear is a good one for plums; but even when this has occurred previously, the trees only had medium crops. It should he definitely understood that summer pruning is not suitable for each tree _ every season. Growers must know'' their trees individually, and also their individual requirements. A tree should be strong in constitution, and growing stronsdv as well; and, as a general rule, a weak f ree should not, be sum-mer-pruned. Weak trees may be success- | fully treated by hard pruning in winter. ■ A tree that is thriving prosperously and bearing systematically needs very little or no summer pruning: while a tree that is growing strongly, is in a good healthv situation, and is yet unfruitful, needs all the attention and consideration that summer pruning can give to it. The subject is one of interest, and worthy of the careful consideration of the many fruit- 1 growers in the Dominion.