Gardening Notes

Evening Post, Volume CV, Issue 142, 16 June 1923, Page 19

Gardening Notes

(By "Experience.")

A correspondent has sent specimens of Pittosporum crassifolium infested with a scale insect. Some species of fly is also said to bo present in large numbers. Nothing can be said about the fly further than that, it is not likely to be doinf? any damage to the plants. Sparrows are said to be busy, and as it is not in the least likely they are after the flies, they certainly will not interfere with the scale. The scale is a native insect, Rhirococcus foEsor, which appears to be partial to the Pittosporum. The presence of this scale can ahvaysba detected by the circular pits it makes in the leaves, which are very similar to the natural pits on the leaves of the native ramarama, Myrtus bullata, which are the origin of the specific name. The specimens received were taken from a hedge;_ the hedge has been cut back and the insects are supposed to have appeared since the cutting- back. Thia is, however, a mistake; the scale has been present for some time. The leaves on the lower and sheltered parts of the plant are first infested, and cutting the young growth away lias brought them into view. -Scale insects can only bY tilled with a contact spray. A poison spray is useless. Evergreen trees will not bear a very strong spray, consequently only the young insects can be killed. For this reason several sprayings are necessary, and they must be timed so as to catch newly hatched scales. In the case of this particular insect, >the young appear to hatch out at all times; there are young insects on the specimens. With regard to material to use, this can be ordinary red spraying oil. used in the proportion of one part of oil to forty parts of water, or kerosene emulsion. The Intter is the better of the two, but is likely to injure the foliage if it is not properly made. There is,- however, no reason why it should be badly made. It only requires care and the use of the proper proportions.

KEROSENE EMULSION.

The material required is kerosene, water, and common household soap. The proportions to use are half the amount of water to the kerosene, and half a pound of soap to^ three gallons of the mixture. Any quantity can be. made if the proportions are adjusted. The method is as follows :—Place one gallon of water in a kerosene tin, and place it on a fire to boil. Shred half a pound of sonp into tha water. Shredded soap will be dissolved by the time the water boils. Take th° tin of water from the fire, and stir well tomsko sure of the soap being thoroughly mixed with the water. Remove some distance from the fire, and add two.gallons or kerosene to the soap-watnr mixture. The mixture must be thoroughly churned for two or three minutes. This can be done by using: a bucket tramp, returning- the discharge to the tin, or with a garden syringe. It would be useless to attempt to. fe it by stirrinir, as the mixture would not be sufficiently cut up. This rnnkes a stock mature, which has to be diluted with wnter according to the use it is put to. For evergreen trees one part emulsion to twelve of water: for tender nlants, one in fifteen. One in twelve is a suitable strength' for s-mnt:----'f vineries, ss advisprl in last Saturday s jiotes. The emulsion sets info a lellv when cold, so wami water'tmi'st.bfl used to dissolve it. Tho em"lsion will keep for any lenc-th of time. Brides beine a (rood insecticide, it U excellent for cleaning paint,l either in th P srpe'ihouse or the dw«llmer. To use it for this n"rnose it should not .he dim.cd. rf R Jrq somp emulsion on a piece of rate, rub it on the nnint. and a minute or two after rub it off with a damn rap. or syringe it "fF in n, greenhouse. It will not damage the paint in any way. I TRAINING HEDGES. I Young hedges are usually subjected to far too much clipping-. It is a common idea that a hedge must be frequently topped to keep it thick at the bottom. Anyone who has the opportunity to observe, and the wit to take advantage of it, cannot fail to see what a j mistake it is. Cutting the growths ' increases the number of shoots at the point where the cut is made, and in no other part. At the outset a hedge plant should be well branched. If it is not natural to the plant to make plenty of branches, it must be pruned down to force them out. If severe cutting back is necessary, it should not be done at the time of planting, for hard cutting is a check, and if the buds have to be forced out, it may take a long- time to get strong growth. All that "should be done at planting time is to trim back young ahoots. If more breaks are wanted at the b*>e, the plants may be cut as hard back as desired the following autumn or spring The roots then having a good hold, new growth will come strong. In England there are thousands of miles of hawthorn hedges. These hedges are made cattte-proof by dense growth. The custom is to" let the plants grow their own way without any check for two years. They are then cut down to within a few inches of the ground. Several strong shoots soon appear in place of the original one, and in a short time a good hedge is obtained. If the young plants were cut down when planted, feeble growth would result, and a hedge would be very slowly formed. Having, secured the necessary number of growth at the bottom, the hedge is thickened by cutting those branches; if they are not there, no amount of cutting of the top will put • them there. Custom dies hard, and it is a difficult matter to persuade most people to refrain from topping, though in doing so they are delaying development in the hedge, and doing no gc3>d. The fact is each hedge_ plant should be treated in accordance with its needs, not all alike. The golden ake ake, Olearia Forsteri, for instance, does not require topping until the desired height' is attained. The habit of this shrub is to make an indefinite number of upright shoots or branches, each of which makes a large number of side branches at frequent intervals. All the trimming required is done 19 the side branches. The holly, most Pittosporums, Oupressus Lawsoniana. and a great many others have this habit. If it is taken advantage of, a hedge is made in half the time it takes under the topping system. This is not a new theory, but is quite old practice. Pittosporum erassifoliura does need topping; the internodes are long, so the tiers of branches are rather far apart. The topping should, however, be done only for the definite purpose of getting breaks where they are wanted, and not at all because topping is a custom.

SWEET PEAS. I The disease known as "stripe disea.se," which causes a good many losses is, so far as I can learn, mainly confined to old gardens. It can be avoided by refraining from the use of stable manure. Many people will be preparing- ground for planting, before long. The advice given is to fertilise the soil with liberal amounts of I superphosphate, small amounts of sulphate ! of potash, and still smaller amounts of sulphate of ammonia. Lime also should be freely used. These fertilisers will •supply all the plant food required just as well as stable manure, and is without the possible ill-effects of manure. STORING TUBEROUS BEGONIAS. There are a number of ways of keeping the tubers through winter. The way that will suit most people best is to keep them in tho pots they were frown in. There are two sources of danger in this method. One danger is from wet rot; this 'is avoided by laying tho pots on their ! side, so that the soil can dry out. The other danger is from dry rot, which is caused by the dry soil drawing the moisture from the tubers. To avoid this, take away sufficient soil to expose the grater part of the tuber. This will prevent the dry soil taking toll from them If the pots are placed under the plant benches, often (lie most convenient place, the moist atmosphere will keep,the tubers plump.