The Blackberry

Sun (Auckland), Volume III, Issue 862, 4 January 1930, Page 23

The Blackberry

Checking Its Spread ITE. the comparatively large amount of time and V money which has been expended in attempts to discover a method for economically checking its spread, blackberry continues to give trouble in many farming districts throughout the Dominion. In the rougher hill country its spread is a very serious problem for many New Zealand farmers.

Before investigating methods for Its destruction it is essential that the farmer should know something of the life of the blackberry. In a normal season in suitable country at the end of autumn the plant has perfected its fruits, and the leaves also gorged full all those cells which are appointed to receive their products with food for use in the future, these cells extend from the tips of the brambles above the ground to the uttermost ends of the roots below the ground. At this time the plant can receive no more food supply from the leaves; it is full. The leaves having finished the job, wither, and fall to the ground. The food they have made is thus stored, like honey in the comb of a beehive. At this time it is in a somewhat crude or unfinished state, and it is not suitable to the production of leaves or new growth above the ground. Also, as the temperature of the air is falling the food goes thick and viscous, and the plant appears to sleep. This is certainly not so. The soil Is now warmer than the air, and the amount of water in the roots and branches it at its lowest ebb, because it has been largely used during the previous spring, summer and autumn. The plant then proceeds to make a network of white absorbent roots, which begin to pass up soil water into that system of cells which is appointed to receive it. These cells extend from the root tips lo the uttermost end of every living bramble attached to the plant. The plant is then full of soil water in one set of cells and leaf food in another. All this time the plant food has been slowly digesting, and in September it is in a highly perfected state, liquid and soluble. The absorbent roots having finished their job can do no more; they change into another state, and prepare so to arrange matters as to enable them to form more absorbent roots next winter, or when a lucky, heavy rain falls in summer. But they- are certainly not in any volume at any time except In winter.

At the middle of October the air temperatures begin to rise, and instantly entities in the branch and leaf buds awaken. Surrounded by food and water they compel new bramble to form. New shoots stream up into the air, new twigs form, new leaf appears—a mass of succulence, soft as young asparagus; the leaves, pale green at first, assume a darker hue, the twigs harden, the flowers appear, and pollenate, fruit sets and ripens, and the leaves working overtime, pour their products again down into the integument of the plant. Carbon Is taken from the gases in the air, affixed by the alchemy in leaves to the water from the soil, and transmuted into all the products required.

It is about thi3 time when crushing by heavy stocking is most effective; grubbing can also be carried out to advantage. In the plant world there are no insurance offices to make good losses by destruction, giving the plant a chance to rise again. Consequently as the whole of the new growth is formed from the previously stored up food, if we destroy the new growth just as it is ready to do work and manufacture a fresh supply we have depleted the working capital of the plant. This will not prevent the plant from beginning again, but the next time the effort will be weaker, and if we wait again until the ’weaker shoots are about ready to work and again destroy them, the plant is in a desperate plight. Nearly all its entities and food supply will have disappeared, and as it possesses no insurance office to make good its losses bacteria will take toll of its root system, and it will perish, or at least it will demand less effort to complete the task of extermination. Although experience lias shown that the economical eradication of the blackberry in rough hill country is an extremely difficult, if uot impossible proposition, there is little excuse for its spread on country which will take the plough and can be top dressed. It is a significant fact that the vine is less in evidence in districts where progressive farming methods predominate.