- Weeds that spread by seed
Some weeds spread mainly by seed. Such weeds should come out before they have a chance to flower and set seed. Ideally such weeds should be out of the garden before they start to flower. Once there are flower buds getting them out is urgent. It is important to learn the different times of year the different weeds flower so you know where to concentrate your effort. Seeding weeds should not go on a compost heap as the seeds can survive there and cause fresh trouble when the compost is spread. An example of a seeding weed in Europe is the dandelion. In this case the root should be taken out as well as the flowers.
- Perennial weeds that spread by growing horizontally underground’’’
Many of the most troublesome weeds are perennials and grow that way. These weeds will not die unless the underground parts of the plant have been removed or killed. The best is to dig the underground parts of the weed out. If this is impossible or too time consuming try to make sure the tops of the weeds are removed very frequently. No plant can survive if its green parts are regularly taken out. Remember where in the garden a troublesome perennial weed is. Check regularly and frequently to ensure that the weed isn’t coming back. When you see a leaf or a shoot take it out and take out as much of the underground plant as you can. Nasty European examples of weeds with underground parts that are very difficult to kill are stinging nettles and bindweed. The underground parts of these plants can survive for many years in a compost heap and should not be put onto one.
- Weeds that spread through making growth above the ground.
There are not many of that type. The European creeping buttercup and Creeping Jenny are examples. These plants should come out before they have a chance to grow stolons. Creeping Jenny can rarely be grown as a cultivated plant provided its growth is limited.
Chemical weedkillers are a great help in the garden. Some kill only the top parts of the weeds but kill that quickly. They are useful especially with annual weeds. Other weedkillers kill the whole plant. These kill more slowly. The weed should survive long enough so that the poison spreads throughout the plant. If the weed doesn’t die at once don’t apply a second dose as this will possibly kill the top before the weedkiller has spread to the underground parts of the plant. Then the underground parts can grow again. If weedkiller gets to cultivated plants it will usually damage them or kill them. An exception is selective weedkillers which kill weeds in lawns without killing the grass. Buy weedkillers from responsible suppliers and read the instructions and safety precautions carefully.
Weedkillers are poisonous to animals and humans as well as plants. Keep them away from pets and children. With some weedkillers pets and children should stay out of the garden for up to a day after they were applied. Check carefully and follow manufacturers instructions.