THE GARDEN.

Otago Daily Times, Issue 21940, 29 April 1933, Page 2

THE GARDEN.

WORK FdR THE WEBRjR 3 pSSk

THE GREENHOUSE AND NURSERY Put in cuttings of roses, fruit’ bushes; and all hardwood plants. Box or pot up old plants of geraniums which were lifted from the flower garden, and put them in a frame or the cool greenhouse. Box up cannas and dahlias and store in a frost-proof shed or under the stage in the greenhouse. Lift and pot or box chrysanthemums which are showing colour and are likely to be spoiled by frost or wet weather. Pot up rooted cuttings of geraniums and pelargoniums intended for the greenhouse. Pinch the tops out of schizanthus seedlings to cause them to branch. Give cinerarias and primulas which have now filled their pots with roots a little liquid manure. THE FLOWER GARDEN Plant out alpine plants in the rock garden and continue to clean and overhaul it. Plant and transplant roses, and all kinds of ornamental trees and shrubs. Weed lawns and topdress them with some fine soil. Continue to plant out spring flowering bulbs and tubers of all kinds. Plant wallflowers, primrose polyanthus, and myosotis. Plant out herbaceous plants, clean off annuals and cut over perennials. Keep leaves raked up and store in heap to provide leaf mould or compost heap. Clip hedges and prune evergreen trees and shrubs. THE VEGETABLE AND FRUIT GARDEN Plant out fruit trees and bushes. Prune gooseberries and currants and cut over old raspberry canes. Clear off all spent crops and manure, dig or trench all vacant ground. Cut oyer asparagus and clean and topdress the beds. Mulch rhubarb with farmyard manure. Lift rhubarb roots intended for forcing and leave them exposed to the weather. Make sowings of peas, beans, lettuce and spinach. CRAB APPLES In the spring I drew'attention to the various species and varieties of crab apples which beautify our gardens with their blossom, which is produced in great abundance. Now, in the autumn, their brightly coloured fruits, which vary in size from that of a pea to that ot a lar<ns cherry or small apple! are most attractive. These are produced along, the slender stems on thin wiry stalks, and, in addition to being very ornamental, they make very nice jelly. Pyrus Baccata, the Siberian Crab, has bright red and yellow fruits each the size of a large cherry, borne on thin stalks one inch to an inch and a-quarter long. Pyrus malus floribunda is a Japanese hybrid between P. Toringo and P. Baccata. Its fruits are small, bright yellow, and the size of a graden pea, inclined to be conical, on thread-like stalks, P.M. atrosanguinea has a weeping habit and its fruit, which are like large cherries, is purple. P. malus var Gprgeous is the most ornamental ot all the crabs at present. It is a lowgrowing variety, specially suitable tor a small town garden. Its fruit, which is borne in abundance even on small trees, is the size, and has the appearance, of a large cherry. P. Eleyi is a hybrid crab forming a graceful compact tree of medium size. It has rich red cherry-like fruits which hang in clusters along the branches and are as attractive as the flowers in spring. Eucalyptus ficifolia is a tree which I always admire in the autumn when it produces quantities of its bright crimson flowers. By some it is considered to be a little tender, and probably on the flat in Dunedin or Christchurch it will be killed by the frost, but on the hills or near the* sea it will stand air the frost we get when once established. It is better to shelter it during the winter for the first two years, until it forms a good, woody stem.

BACTERIA IN THE SOIL 'Most‘gardeners are aware that in addition to the insect and fungoid life In the soil which is obvious there is certain microscopic life which though not evident ■to the naked eye still plays a very important part in the health and growth of the plants. It is largely on account of this life , that sterilisation of the soil is so important, and also that the mechanical condition of the soil is much more important than its chemical composition, for it does not matter how rich it may be in plant food, for if the cultivation, aeration and temperature are not correct the plants cannot thrive. There arc two distinct types of soil life, one which Is useful to the plant, and one which is harmful. We will take the useful types first. Certain types of fungi grow on the roots of plants doing any harm and in some cases indeed markedly benefit them, The association of plant roots and fungi was first observed in 1885 by Frank, who described it and named it Mycorrhiza or fungus root. His observations were on trees, but large numbers of plants are similarly associated with fungi, especially on soils

NOTES BY TANNOCK, A.H.R.H.S.

rich in humus or organic matter, with a tendency to be sour. In fact, it may generally be taken that the presence of mycorrhiza is necessary for the growth of pines, rhododendrons, heaths and other members of the erica family, and when conditions are changed so that mycorrhiza cannot live, the plants become yellow in colour and unhealthy. Such conditions are brought about when we apply lime, wood ashes, or any kind of alkaline substance to the soil. In their association there is no evidence of injurious parasiticism but rather a delicately balanced and mutually beneficial relation between the fungus and the plant, depending on the physiological conditions of the mycelium and root, and is very susceptable to the change in environment. In addition to pines, heaths and rhododendrons, orchids and plants without chlorophyll or leaf green will not grow, or will grow only under difficulty unless the fungus is present. At one of its stages this fungus is quite evident, and if the roots of seedling pinus radiata, or rhododendrons and heaths are examined it will be seen that the fine, fibry roots are permeated by strands of white fungus. Some people are liable to confuse this fungus with that which causes dry rot in timber, and they are concerned regarding pine needles, woody twigs and leaves, which are often found in the soil. These do not do any harm to plants with micorrhiza nor, in fact, to any living tissue. It has been noticed that seedlings of pinus radiata do better the second year than the first, and it has been suggested that it would be an advantage to inoculate the seed bed by using some soil from old seed beds or from the bush for covering. Historically bacteria are by .far the most important organisms in the soil. They seem to be the same all over the world, different kinds being associated with different kinds of plants. Though they may appear the same, they are not interchangable, and kinds which inhabit the roots of broom are apparently of no use to lucerne, lupines or crotolarias. It has long been known that members of the pea and bean family are able to grow and thrive in soils where, other plants would starve. The luxuriant growth of lupines on the sand dunes is a very good example of this phenomenon. These bacteria, when they puncture the tissue of the root of the host, cause a malformation which gradually grows into a nodule, and as the number of the bacteria increase these nodules increase in size. The bacteria have the power of obtaining their supplies of nitrogen from the air or from inorganic sources, and part of this they pass on to the living plants. Taking advantage of this process farmers and gardeners grow crops of leguminous plants such as lupines and crotolaria, which if cut and removed leave quantities of these nitrogen-con-taining nodules in the soil, which are available for the succeeding crops, or for the crops with which they were associated. It is really better to return the whole of the plant to the soil and in this way it is convenient to obtain a supply of organic matter which is most important in these days of scarcity of farmyard manure. To get the best of such a catch crop it should be cut and dug in while in flower, before it wastes any of its substances in forming seeds or tough tissue which take a long time to rot.

The bacteria in the pod-bearing plants require exactly the opposite conditions to the mycorrhiza of pines and ericaceae, they like an alkaline soil with a reasonable supply of free lime to keep it in that condition. To get quick results it is usual to sow inoculated seed or to scatter some of the soil from au area which has already produced the same kind of pod crop and rake or harrow it, in. Of course, when soil is sterilised by heat these as well as the harmful bacteria are destroyed, but they are easily put back again in small areas such as we have in our gardens.