WEEDS.

Otago Witness, Issue 3196, 16 June 1915, Page 17

WEEDS.

HOARY CRESS (LEPIDIUM DR ABA). This weed is increasing very rapidly, and in some parts of North Canterbury 1 have seen paetdooks cf crops and grass nearly white when this was in full flower.

It is a native of Europe, Asia, and Africa; is a perennial, with deep-penetrat-ing roots which contain much stored food. Pieces of the root will grow, as in the case of Californian thistle, twitch, etc. It grows from Ift to 3ft high; has oblong leaves, the lower’ stalked; the upper have an arrow-headed base which clasps the stem. The flowers are of a whitish colour, in short corymbose clusters somewhat like that of the carrot. Flowering occurs in October and November. The seed-pods are small, flattened, and heart-shaped, with one seed in each cell. It is a prolific seeder and difficult to eradicate when once it is established. Summer fallowing, deep ploughing, and frequent stirrings are the best means of eradication. Cutting to prevent seeding and frequent hoeing will often give good results, and any roots thus brought to the surface should be burnt. This weed, as I have already said, is becoming very^prevalent, and requires far more attention than it is receiving. I have seen it cultivated in gardens and shrubberies. ST. JOHN’S WORT (HYPERICUM PERFORATUM). This is ahother of the “creeping weeds,” is a perennial, and a native of Europe, Asia, and Africa. Erect stem, from 2ft to 3ft high leaves oblong and about half an inch long, of a bluish-green tint; flowers bright yellow dotted with black, in terminal clusters, which when crushed stain the hand yellow. The plant contains an oil of some slight medicinal value, but this oil and the woody nature of the plant renders it injurious in fodder. It has deeply-penetrating roots, and forms short runners, pieces of which if broken off will grow. It is most troublesome in pasture land, as it attains such a height that it overtops all but the tallest and coarsest grasses. This weed is not troublesome in England, as there it is not allowed to get established. It being a perennial and spreading from the roots as well as seed, deep ploughing in a dry season, if followed by a potato© crop, does not give the plant a chance to get away if the potatoes are kept as clean as they should be. A root crop may be required thfe following year before the land is safe for grain. Since this plant is a heavy seeder - , it must bo out down before the seeds are formed. PENNYROYAL. This is a most troublesome plant, and causes a great deal of loss to farmers. Several have asked through the Journal of Agriculture for information as to the best means of controlling it. Some years ago X noticed, in passing a farmer’s barn, that the pennyroyal had been killed where the farmer had thrown out some brine. I passed the same place a little later, and found the grass had come up again round the edges which had received the smallest dressing of salt. The pennyroyal did not come up either that year or the next. I made several experiments, and found that a light dressing of salt would check pennyroyal,- whilst the grasses remained uninjured. I found, however, that different soils needed different quantities. Some years after this I went to a district where the pennyroyal was growing luxuriously on the cricket ground. It cost £2 a year to keep it cut, and the result was not satisfactory. I obtained about 3gcwt of salt and applied it to the ground. The pennyroyal died down at once, and though the land was dressed some 10 years ago, the cricket ground is still free of pennyroyal, while the surrounding paddock is covered with a thick mat of the plant. The weed has started to grow several times, but the cattle keep the ground so closely cropped that it has soon died out. I have used the salt to clear tennis lawns and paths of this weed, and have not had a failure.

A warning is, however, necessary. Too heavy a dressing will kill the grass as well as the pennyroyal. From 3cwfc to 4cwt to the acre will ho sufficient. Anyone_ who wishes to use this remedy should experiment a littlo for himself. CALIFORNIAN THISTLE. It having been declared in Southland that cutting the Californian thistle is of no avail, it may he pointed out that in the North Otago district repeated experience has demonstrated that this method of eradication is entirely successful. Even on farms of rich volcanic land, where the thistle has been cut every year just at the flowering’

stage, and where it was exceptionally bad five years ago, to-day a marked improvement is noticeable. In some paddocks the vitality of the thistle is so weakened where it has not been altogether destroyed that a few hours’ work is now sufficient to deal with it, whereas it formerly took several days with the mower and horses. Take the far-famed Totara Estate. Here the thistle had a very strong hold, and the land, being rich, it was most difficult to deal with. Now, by repeated cutting the thistle has disappeared altogether in many places, while whore it still persists it is so weak that its control is now quite an insignificant matter. A largo number of North Otago farmers will bear mo out that cutting the thistle every year when in the flowering stage has done marvels in the way of destroying acres upon acres of the weed in their district. fAll the above references to weeds are culled from the Journal of Agriculture for May, and are the expressed opinions of various members of the Fields Division.]