KILLING BLACKBERRIES.

New Zealand Herald, Volume LX, Issue 18455, 19 July 1923, Page 12

KILLING BLACKBERRIES.

CUTTING AND SPRAYING.

Though the spread of the blackberry bramble to clean areas is mostly due to its seed being carried there, in established clumps its increase is usually due to the long arching or trailing brambles becoming rooted at the tips, and by these means commencing the formation of a fresh clump, which, unless checked, will ultimately become merged .■> into one tangled mass. Blackberies have a perennial rootstock without underground creeping, and their propagation is usually by the means above " mentioned. I One of the first steps towards blackberry control should be to prevent this plant from' fruiting wherever possible. This could be accomplished by either outting down the brambles, burning them, or by spraying the bushes with chemicals. On cultivable land there need not .be such very great difficulty in blackberry eradication. If the clumps or masses are old established, these should be cut round by. means of a horse-drawn mowing machine, or else cut with a slasher. The cut material should then Be thrown back on to the mass of uncut brambles and left until fairly dry. Some • free-burning material, such as bushes or straw should be added so as to ensure a good burn. If the burn is not a good one by reason of insufficient material, the brambles are merely scorched and toughened, and are then more difficult to cut than they wore previous to being fired. If there has been a good clean burn the roots can be completely dug out and burnt, or the land can be ploughed during the warm weather, ana often enough to .prevent any new shoots a.'ising and thus feeding any root stocks remaining in tho ground. Eepeated cutting of new shoots will starve the root stocks, ultimately killing them; but cutting, to be effective, must frequent and thorough, the chief aim being to prevent leaf formation and thus starving the roots. The great difficulty with blackberry control is, when this plant is growing on land of a' rocky or stony nature or on creek or river frontages, or in situations that make cultivation either impracticable or undesirable on account of the danger of soil erosion during floods. In such places, cutting to prevent fruiting will control the 'plant without eradicating it, usually two cuttings a year being sufficient to stop its further spread. This 13 unsatisfactory, because the work has to be repeated year after year. It is cheaper to kill the roots and have done with -them, and for this purpose chemicals could be employed. If an arsenical preparation is used the branches should first be cut and burnt as already described; otherwise, if the bushes are sprayed with arsenic without previous cutting and burning, the leaves drop off, leaving a jungle of loose canes that make their removal difficult afterwards, either by fire or by cutting. clean burn has been obtained, the shoots that will afterwards spring up can be easily destroyed by the arsenical spray *vwy time they make their appearance. Sr£t a L'L at the „ P resent time on the I^lAiKi-feirr^r 1 S'J 1 . Allowing mixture can be recommended as havinc giVen *»< «"& against blackberries L 8" good reßults Boil together lib. white arsenic 21b washing soda, and two gallons 'water" When dissolving use a slow fire, onlv 2; lowing the mixture to simmer- if th* R n ration is boiled rapidly there is a risk of the material boiling over. The liquid should become quite clear in about 30 minutes then make it up to ten gallons. It is not advisable to make a. concentrated stock of dissolved arsenic, as in all probability it will crystallise on becoming i cold, necessitating it all being boiled over again. . In spraying with arsenical mixtures one should stand with his back to the wind. so that the material will be carried away from the operator. ' As arsenical preparations are exceedingly poisonous, stock should always bo removed from land beimj heated with this chemiaal. i