It is not essential for you as a gardener to know the names of weeds, for you will soon recognize them as having no garden value and realize that they multiply rapidly to the detriment of worthy plants, robbing them of light, water and nourishment.
No gardener should have sleepless nights because there are a few weeds in the garden, provided that they are not unsightly or growing so aggressively that they prevent your valued plants from thriving.
The worst aspect of having weeds in the garden is that they shelter and provide food for pests like aphids, thrips, red spider mites and eel worm, or act as hosts for bacteria and fungi so that diseases can be transferred to healthy plants.
For this reason it is essential to remove weeds scrupulously from the vegetable garden and its surroundings or wherever you are growing prize flowers. The odd weed in the lawn or down the garden path must be removed more for aesthetic than for the above reasons.
The age-old method of digging out weeds by hand is always best if it is done thoroughly and regularly. Sometimes weeds multiply so prolifically that the busy gardener cannot cope with them, especially when time is scarce. A weed eater can help you here in the short term.
Chemical weedkillers can help you, but must be used with care, or they may harm nearby plants or ruin a whole crop. Certain weeds cannot be controlled easily even with these chemicals, so that vigilance is needed to prevent them from becoming a curse.
Such weeds are perennials which have numerous corms, bulbs or nutlets deep underground, such as Sorrel (Oxalis), Wild Onion (Allium) or Nutgrass (Cyperus).
You need to dig deeply, especially when the plants are small, and wage constant war on them. Grasses like Bermuda-grass (Cynodon dactylon) or Kikuyu have underground runners and are difficult to eradicate as they store food and come up repeatedly after removal.
It is impossible to eradicate weeds completely as new infestations occur repeatedly. One can only attempt to control the growth of weeds so that they do not ruin one’s efforts in gardening.
It is essential to eradicate weeds when they are young, whether weeding by hand or when using chemicals. If you can remove weeds before they form seeds, you can reduce work in future years; as expressed in the old saying, “One year’s seeding means seven years’ weeding”.
Weed Control by Hand.
It is much easier to dig out weeds when they have just started growth than when they have grown large and there is less risk to nearby plant roots if they are pulled out before the mature weed has developed a strong root.
Use a claw-like instrument or a fork to scratch at the surface of the soil, but do not chop at the ground between plants with a hoe for fear of destroying their roots, except in the vegetable garden, where you must leave enough space between rows to enter and eradicate weeds.
Do not dig the soil while it is wet as this spreads disease and does not destroy the weeds so quickly. Loosening the surface of the soil in order to prevent a hard crust from forming not only allows oxygen to enter, but checks weed growth.
Avoid leaving large patches of soil bare as they are quickly over-run by weeds like Nutgrass which are difficult to eradicate. Weeds on lawns should be removed with a “weed puller tool” or two-tined fork that does not make large holes in the grass.
In order to make weeding easier on a large bed set aside for annuals or on a bare piece of ground prepared for lawn, water it two or three weeks in advance of planting in order to start weed growth and then dig over the surface to remove most of the weeds before planting.
Weeds and Compost.
Avoid adding weeds that have formed seeds to the compost. Many weed seeds are resistant even if compost is made by the best methods, while seeds on the outside of the heap seldom get hot enough to be destroyed.
Young annual seedlings of weeds can be added safely. Never add weeds that have corms, nutlets or bulbs attached to them, or they will be distributed all over the garden.
Burn all such weeds or put them into the rubbish bin.
Never add weeds that have been killed by chemical weedkillers to the compost.
Weed Control by Chemical Weedkillers.
These do not solve the weed problem completely and, as you must take precautions in using them, their use is not always convenient or advisable. They can be used mainly to control weeds on large areas of newly planted lawn or on pavements or gravel paths. Special weedkillers can be used to kill suckering trees.
There are several types of weedkillers, many of which are still in the development stage. Always follow the manufacturer’s instructions implicitly when using them.
All weedkillers should be used on calm days when there is not wind to blow the spray on to nearby plants or shrubs. It is best to water them directly on to the soil or weeds with a watering can, as fine sprays from a pump drift more easily.
Keep separate equipment solely for applying weedkillers, in order to avoid injury to other plants. Wash utensils immediately after use with clean water. If you need to use the equipment for other plants, wash thoroughly with washing soda and warm water. Do not allow weedkillers to come in contact with the eyes or skin and keep them away from open flames.
How to Use Weedkillers
To Destroy Garden Weeds.
For ordinary annual weeds like chickweed, clover, and many other broad-leaved weeds, as well as some annual grasses, use a selective weedkiller, like 2,4-D and its chemical derivatives. 2,4-D may be applied to bare soil before the weeds appear (pre-emergence treatment) or soon after they appear (post-emergence treatment).
It can be used on lawns after planting, leaving the grass unharmed. Certain weedkillers can be used on strawberries, gladioli, Rhododendron and other specified plants.
It is essential to apply 2,4-D to weeds when they are young and growing actively, from the time that they first appear until they are about three or four weeks old.
The younger they are, the more easily they are destroyed. As soon as they have formed seeds or stopped growing, or even grow poorly during drought, the weedkiller will be much less effective.
It is best to apply 2,4-D to bare ground before the weeds appear and then not to disturb the soil for two to three weeks. The soil or the weed foliage must be wetted thoroughly.
When treating bare ground, it is best to water the weedkiller on to moist soil, or it can be watered on to dry soil if rain is imminent within a day or two. If growing weeds are treated, however, rain within 12 hours will wash off the weedkiller before it has had time to be absorbed properly into the foliage.
New lawns may be treated about 10 days after planting the grass. Strawberry beds should not be sprayed unless the plants have had 10 days in which to become established. You may have to repeat the spray at least once on lawns and three or four times on patches of weeds, at 10-day intervals.
To Destroy Trees, Shrubs and Brambles.
Woody plants that are difficult to eradicate such as Poplars or Gums, which send up new growth from stumps or pieces of root left in the ground, or prickly jointed Cactus and Brambles, or rampant shrubs that have become a pest may be killed by means of a special brush-killer known as 2,4,5-T. Do not use this on lawns or near any desirable plant. Keep the container sealed and store it away from any fertilizers, insecticides or other garden materials.
To kill a large tree, make cuts around the trunk with a chainsaw or axe, about 60 cm from the base, and paint them and the bark below with 2,4,5-T mixed with diesel oil or paraffin.
If the tree is felled, apply this to the stump within 24 hours, soaking the cut surface and the bark to the point of run-off.
Re-treat the stump if growth appears again. Small shrubs and saplings can be sprayed completely. Otherwise, cut down shrubs and treat the stems. Brambles must be sprayed when in full leaf and any new growth sprayed again in the following season.
To Destroy all Plants, Grasses and Weeds
On paths and tennis courts, one can use a non-selective or total weedkiller. A product such as RM43 can be used for this purpose.
Such chemicals are best confined to the experienced landscape contractor or farmer. In any case, the treatment would have to be repeated after a few months or a year to be really effective.