When I was a child gardeners all over the world spent a great deal of time in the garden on their hands and knees pulling out or digging out weeds. It was time-consuming and time-wasting work, not to mention back-breaking for the tall ones. Annual weeds could then and can now be easily controlled and cut down with the garden hoe, but it must be done before they flower because if they produce seed you’ll have months of weed. Perennial weeds are a very different matter. They don’t need to produce great quantities of seed, for they can live for years. Their deep and widespread root system takes care of them, and often makes them difficult to eradicate. Just take off the leafy top and they will produce another one! Cut the root up and often you’re just be propagating them. Well, time and science have altered all of that.
The gardener now has chemicals in his potting shed especially designed to control and prevent weed growth. It’s not a matter of physically damaging the weeds to control them (hoeing them out), although that still has an important part to play. Now it is a matter of applying chemicals either to the weeds you wish to control, or to the ground you want to keep clear of weeds.
Contact weedkillers are herbicides which are sprayed or watered onto weeds and kill the parts of the plants they touch. They are generally non-selective and of a corrosive nature like Gramoxone or Roundup which kill the parts of the plant they contact. Alternatively, they may be selective weedkillers (usually hormone based), killing only certain kinds of plants like broad-leaved weeds alone, or grasses alone. In this case the chemical is absorbed into the plant’s system, penetrates to all parts, and kills all parts no matter how tall the plant is or how deep it has grown. This kind of action is called systemic, and includes chemicals like 2-4d (for broad-leaved weeds), and Dalapon (for killing only members of the grass family and other monocotyledons).
Preventative weedkillers: A moment ago I mentioned chemicals which are applied to keep the ground clear of weeds, which prevent weed germination and will kill those that start to germinate. Such a one is Simazine which is not available in Guyana as far as I know, but which has been used widely in Europe and North America since the 1960s. It is a white powder just mixed and applied either by a sprayer or a watering can, and which has caused problems with certain crops such as strawberries, where it has been used for many years up to the point where there has been a dangerous build-up of the concentrate in the soil. In my view it’s good only to use on ground which is going to be kept free of weeds and will not be used for other crops.
Now whatever chemical you decide to use, there are certain important things you have to bear in mind when spraying herbicides (a fancy name for weedkillers). There’s a lot of ‘always’ involved.
Always:
(1) avoid getting the chemical on your hands, and always wear rubber gloves;
(2) avoid getting the chemical on plants you want to keep;
(3) remember never to spray any chemicals when there’s any breeze because it might get on you and on to valuable plants you have;
(4) remember never to spray during the hottest time of the day;
(5) remember never to spray near water and never wash the equipment out in a ditch or trench;
(6) lock up your pets and children when you’re spraying, and keep them off the grass;
(7) follow the manufacturer’s instructions precisely.
Hormone based herbicides should never be applied under trees because they evaporate in hot weather, and the vapour may kill the trees. Until next week may your God go with you wherever you may go.