Fat hen

(Chenopodium album) Fat hen is a common annual weed that appears throughout the garden. It spreads readily, each plant producing thousands of seeds, and quickly becomes a nuisance.

What is fat hen?

Fat hen, sometimes called white goosefoot, is a very common annual weed, appearing in both cultivated and uncultivated bare soil.

Plants grow quickly, and each one produces thousands of seeds each year, so quickly covers beds and borders and grows through cultivated plants.

These seeds can 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 do they grow?

Beds
Borders
Gravel paths
Waste or uncultivated ground

Appearance

Fat hen grows upright, reaching variable heights of 10-120cm (4in-4ft) high. The leaves are variable in shape and size. The first leaves near the base are toothed and roughly diamond-shaped, becoming entire and rhomboid further up the stems. They are waxy coated and mealy, with a whitish coating on the underside. The small, whitish flowers are produced in dense, branched flower heads that then produce numerous seed pods and seeds.

How to control fat hen

As with most weeds, never allow fat hen 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.

Natural control

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.

Weedkillers

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

Any weedkiller can be used to control and kill fat hen 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 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.

Prevention

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.