(Senecio vulgaris) Groundsel is a common annual weed that appears throughout the garden. It spreads readily, each plant producing numerous seeds, and quickly becomes a nuisance.
What is groundsel?
Groundsel is a very common annual weed, appearing in both cultivated and uncultivated bare soil.
Plants grow quickly, and each one produces up to a thousand seeds. These can germinate quickly, producing several generations of plants each year. These quickly cover beds and borders and grow through cultivated plants.
These seeds can also remain dormant in the ground for several years. And as “One year’s seeding means seven years weeding”, allowing plants to flower and produce seeds, means several years of trying to control and remove it.
Where does it grow?
- Gravel paths
- Waste or uncultivated ground
Groundsel grows upright, reaching up to 60cm (2ft) high. The leaves are variable in shape and size, with rounded lobes that are sharp to rounded saw-toothed, usually covered with soft, smooth, fine hairs.
The stems branch out into clusters of yellow flower heads from April to October. These produce downy heads of seeds, which look similar to those of dandelions. These are blown several yards by the wind.
How to control groundsel
As with most weeds, never allow groundsel to become established, and certainly don’t allow it to flower and produce seeds. This will make it more difficult, and more time consuming, to fully control. Early identification and eradication is important to stop it taking over the garden.
Regularly hoeing seedlings and young plants as soon as you see them is the quickest and easiest method of control. The aim of hoeing is to sever the weed stems at or just below ground level, cutting the top growth from its roots. A sharp hoe blade will make this even quicker and easier, so always sharpen the hoe blade before using it. Hoeing on a warm and/or windy day will mean plants quickly dehydrate and die.
Digging out the plants when they are more established is more time consuming and more difficult – especially where they’re growing among wanted plants.
Flame guns and weeders that use an electric current are also effective in some locations.
Covering bare soil with weed-control membrane (landscape fabric) or even thick black polythene will exclude light and prevent seeds germinating. As will mulching the soil with organic matter, such as a bark mulch. For mulches to work properly, they need to be a minimum of 5cm (2in) thick, but 7.5cm (3in) deep works better.
There are a number of weed control options available to treat groundsel. In addition to traditional weedkillers there are now also a range of more natural alternatives.
Any weedkiller can be used to control and kill groundsel in beds, borders, waste ground and on paths. 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.
To ensure weedkillers work more effectively:
- Spray the leaves when the plants are actively growing; 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.
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.
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.
- Hand fork
- Weeding tools
- Weed-control membrane