On the surface they can germinate, as you discover later.
Their vigorous growth makes them real troublemakers, as they beat choice plants in the competition for water, nutrients and light. Or, tenacious perennial weeds can really get a hold, even in well kept gardens. With these garden thugs, you can break their roots with hoeing and digging without killing them - in fact, this can increase their infestation! There are two main ways to get on top with controlling persistent weeds of either type: Prevention - discourage by using good basic gardening techniques. Cure - remove by manual, mechanical or chemical means.
You'll never be able to completely stop weeds from popping up in your garden, but there are ways to ensure they have less places to grow. Bare patches of soil will quickly be colonised by both annual and perennial weeds, so a well-stocked border is less likely to support a thriving population of these pesky plants. If you have gaps, plug them by planting ground covering plants. Alternatively mulch bare soil with a thick, 8cm (3in), layer of bark chippings, well-rotted manure or leaf mould in the spring. Not only will this prevent weeds from growing, but it will help to retain moisture in the soil. If you have a large area of bare soil, such as an unused patch at the allotment, cover with plastic, landscape material or even old carpet to prevent weeds from germinating.
Annual weed seeds can survive for years in the soil, waiting for the perfect conditions to grow. They germinate at lower temperatures than most garden plants and can grow and set seed very quickly. Its important to recognise them at the seedling stage, so you can eliminate them without accidentally removing your flower or vegetable seedlings.
Remove annual weeds from bare patches of soil by hand or with a hoe, severing the tops from the roots, before they have a chance to produce seed and spread. Use a hand fork to lever perennial weeds from the soil or use a special long handed weeding tool. It is important to remove all the roots, as some weeds can regrow from any bits left behind. Herbicides can also damage garden plants so are best avoided unless absolutely necessary. Bindweed, which is a serious problem for some, sometimes winds itself into shrubs and is best destroyed by painting the leaves with a herbicide gel, which will be taken down to the roots.
Use an old knife or a special paving brush, with an angled head of wire bristles, to scrape weeds out of the gaps between paving slabs. If you have large areas of paving that need weeding, try a gas powered flame gun. These are hand held, lightweight gadgets - all you do is pass the flame over the weeds, the tops blacken and quickly die.
Many shallow rooted, rosette forming lawn weeds can be removed with a daisy grubber, while tap-rooted weeds can be hoicked out of turf with a long-handled weed tool. Alternatively, weeds can also be treated with a herbicide gel brushed onto the leaves. This will only affect the weeds treated. Moss and many other lawn weeds can be prevented by keeping the lawn healthy. Aerate, spike and rake annually to improve drainage and remove debris. If you have a problem with coarse grasses in the lawn, they can be controlled by slashing through the crowns with a knife before mowing, while weeds that spread by runners can be weakened by raking the stems upright before cutting. If you have a serious weed problem, use a weed and feed product, ensuring that the formulation is for the right time of year. These are usually for spring or autumn application.
Moss, algae and weeds can sometimes overrun pots and rob moisture from the roots of plants. Pull out by hand – if necessary scoop off the surface layer – and add a layer of fresh compost. An ornamental mulch of pebbles, shells or glass chippings will prevent weeds from returning.
Common annual weeds
Hairy bittercress (Cardamine hirsuta) - bare soil and pot
Groundsel (Senecio vulgaris) - bare soil
Sun spurge (Euphorbia helioscopia) - bare soil
Chickweed (Stellaria media) - bare soil
Fat Hen (Chenopodium album) - allotments
Common perennial weeds
Dandelion (Taraxacum officinale) - lawns and bare soil.
Daisy (Bellis perennis) - lawns
Annual meadow grass (Poa annua) - lawns
Japanese knotweed (Polygonum cuspidatum) - rural gardens
Creeping buttercup (Ranunculus repens) - damp borders or lawn
Bindweed
Bindweed ground elder and couch grass are weeds with underground stems. The weeds spread by rhizomes that produce shoots and roots and extend growth below ground. As this activity is invisible, these weeds can pose a real problem.
Hedge bindweed grows from rhizome fragments and will search for a structure to climb and eventually smother. Young shoots tend to have purple tips to the stems.
Cleavers
Cleavers and burdock are annual weeds with sticky leaves and seeds. Although quick to smother other plants, you can control them easily by pulling them, as the stems and roots are very weak. The surface of the seed is covered in fine hooks that attach themselves to another surface, such as animal fur or clothing. Later these detach and you have weeds in an entirely different place from where the seed originated.
Creeping buttercup
Bramble and creeping buttercup are weeds that produce stolons (horiztonal stems), which in turn develop roots on these extending stems, making it easy for the plant to spread.
Dandelion
The dandelion is a weed that develops small, ripe seeds. The seeds for their part grow a cluster of fine hairs, which help to carry the seed on the wind.
Hairy bittercress
This is a fast-growing annual weed that seeds very shortly after flowering, so needs quick action to prevent a rapid problem. The seeds of hairy bittercress ripen in pods that dry out, and then split open to expel seeds up to 1m (3ft) away.
Horsetail
Hosetail is a very difficult perennial weed to control. New shoots emerge in spring above black rhizomes that spread deep underground and may be distributed further by digging.
Lesser celandine
Lesser celandine forms swollen roots that detach from the main plant and then go on to support a new plant. This perennial appears early in spring and has leaves that look a little like cress. New seedlings will be smaller than the established plants, which produce bright-yellow flowers, followed by seed. The plant vanishes by midsummer, but digging may disperse the root tubers.
Dealing with the pulled up weeds
This can be a bit of a problem when hand-weeding perennial weeds and having dug up your tornado-proof, phoenix-like foe, putting it on the compost heap can be a bit like sending it on a holiday to build up its strength and recover again. Don't compost perennial weed roots unless you are certain you can kill them. One way of doing this is to put them to one side in a separate bucket or container.