Annual weeds

(Numerous species) Annual weeds are easy to deal with, especially if controlled as seedlings or young plants. Then, they don’t get out of control and become a time-consuming problem.

Annuals are plants that germinate from seed, grow, flower and set seed, so completing their lifecycle, within one year. Some, such as hairy bitter cress (Cardamine hirsuta), do this in a couple of weeks or a couple of months, so several generations can appear each year. Some will also grow, and even flower, during mild weather in winter.

Generally annuals produce lots of seeds, and as these can remain dormant in the ground for several years – “One year’s seeding means seven years weeding” – allowing weeds to flower and produce seeds, sets you up for many years of weeding!

As any plant “growing in the wrong place” is regarded as a weed, cultivated plants allowed to set seeds and produce lots of young plants where they’re not wanted can be regarded as “weeds”.

Many of our weedy species are naturally-occurring or wildflowers, so make sure these don’t produce seeds, unless you need or want more plants to cover larger areas of your garden.

• Beds
• Borders
• Lawns
• Gravel paths
• Between paving slabs
• Waste or uncultivated ground

There is a huge range of annual weeds that will appear in our gardens. Some are more troublesome than others. It’s their ability to produce up to hundreds of seeds and seedlings if allowed to, that creates the problems and ensures we regard them as weeds.

Common annual weeds include the following

Annual meadow grass (Poa annua)
Annual mercury (Mercurialis annua)
Charlock (Sinapis arvensis)
Chickweed (Stellaria media)
Cleavers, goosegrass (Galium aparine)
Common purslane (Portulaca oleracea)
Fat hen (Chenopodium album)
Field pennycress (Thlaspi arvense)
Groundsel (Senecio vulgaris)
Hairy bittercress (Cardamine hirsuta)
Henbit (Lamium amplexicaule)
Scarlet pimpernel (Anagallis arvensis)
Shepherd’s purse (Capsella bursa-pastoris)
Sow thistles (Sonchus species)

As with most weeds, never allow them to become established, and certainly don’t allow them to flower and produce seeds. This will make it more difficult, and more time consuming, to fully control them. Early identification and eradication is important to stop them taking over the garden.

Annual weeds have simple and generally shallow root systems, so hoeing them, pulling or digging them up is usually enough to control them.

There are a number of weed control options available to treat annual weeds. In addition to traditional weedkillers there are now also a range of more natural alternatives.

Any weedkiller can be used to control and kill annual weeds. Those marketed as “fast acting” are contact weedkillers – killing or damaging the plant tissue they are sprayed onto or make contact with. These tend to be based on “naturally-occurring” active ingredients, such as acetic acid and natural fatty acids.

Systemic weedkillers, that also kill the roots can also be used on annual weeds.

To ensure weedkillers work more effectively:

• Spray the leaves when the weeds are growing actively; this is mainly from March/April to September/October. Contact weedkillers will have some effect if used during the colder weather in winter.
• Use a fine spray to thoroughly coat the leaves in small droplets.
• During the summer, spray in the evening to prevent the spray evaporating and to give maximum time for the spray to work. In spring or if overnight dew is forecast, spray earlier in the day to allow the spray to dry before dew falls.

Most weedkillers (except lawn weedkillers) are total weedkillers – that is they will damage or kill any plants whose leaves they are sprayed onto. Make sure you keep the spray off wanted plants – including lawns – and, if necessary protect plants by covering with polythene or similar when spraying.

Use weedkillers safely. Always read the label and product information before use.

There are a number of weed control options available to treat nettles. In addition to traditional weedkillers there are now also a range of more natural alternatives.

Contact weedkillers will burn and kill the foliage, but will have no effect on the roots, which will continue to grow, produce new leafy growth and spread further. Constant spraying whenever new leaves are produced will weaken and kill it in time.

For best results, spray with a systemic weedkiller. A systemic weedkiller, which is absorbed by the leaves, then moves down to the roots to kill them. “Tough weed” formulations will give better control. Older, woody growth may not absorb the weedkiller as effectively as younger growth. In which case, for well-established clumps of nettles, cut down the plants to ground level and then treat the resulting new growth.

To ensure the weedkiller works effectively:

• Spray the leaves when the nettles are growing actively; this is mainly from March/April to September/October.
• The larger the leaf area present, the greater the amount of weedkiller that can be absorbed. So don’t bother spraying when the growth first emerges through the soil – wait until the leaves grow larger.
• Use a fine spray to thoroughly coat the leaves in small droplets.
• During the summer, spray in the evening to prevent the spray evaporating and to give maximum time for the spray to be absorbed. In spring or if overnight dew is forecast, spray earlier in the day to allow the spray to dry before dew falls.
• One application of weedkiller may not completely kill the nettles. You may need to spray once, allow it to die down, and then spray any regrowth again. Three or more applications a year may be needed to completely kill it, depending on how extensive the root system is.

Most contact weedkillers are total weedkillers – that is they will damage or kill any plants whose leaves they are sprayed on. Make sure you keep the spray off wanted plants – including lawns – and, if necessary protect plants by covering with polythene or similar when spraying.

Gel products, which is dabbed onto, and sticks to, the weed leaves, may be a better option when trying to treat nettles growing close to wanted plants, where drift of the spray would damage them.

In lawns, use a good lawn weedkiller.

Use weedkillers safely. Always read the label and product information before use.

Never allow plants to flower and set seed. Although this should be pretty easy in your garden, it’s more difficult to stop seeds blowing in from a neighbour’s garden, any surrounding fields and waste ground and even further afield.

• Spade
• Fork
• Hand fork
• Hoe
• Weed-control membrane
• Weed killers