What is chickweed?

Chickweed is a common annual weed of both cultivated and bare ground. Although it prefers a rich soil, and so can be a good indicator of soil fertility, it is adaptable to a range of growing conditions. Plants produce large quantities of quickly germinating seed throughout the year and can easily smother beds and borders if not promptly controlled.

Appearance

A central mass of shallow, fibrous roots gives rise to a vigorous clump of prostrate stems to 35cm (13in) tall, with a single line of hairs along their length. Bright green pointed oval leaves are borne in opposite pairs which fold towards each other in the evening to protect tender new growth.

Tiny, white, star-shaped flowers are borne singly in leaf axils and in clusters at stem tips at any time of year, but are most noticeable in spring and autumn. The flowers have 5 very deeply divided petals and last only a day or two.

The problem

Seeds are produced in large quantities, with an individual plant able to produce 1300 seeds. It takes only 5-6 weeks from germination to seed dispersal and plants are capable of 4-5 generations per year.

The seeds are also easily distributed in a number of ways, including in top-soil, compost, manures and on muddy boots and can remain viable after passing through the digestive tracts of birds and animals and following immersion in salt water. Seed buried in soil can remain viable for up to 25 years and will germinate quickly if brought to the surface by cultivation.

Although individual plants are relatively easy to control, the sheer number of seeds produced each year mean the task of controlling this weed inevitably needs to be carried out regularly.  

Control

Non-weedkiller control

Although time-consuming, hand-weeding or carefully hoeing beds and borders can be an effective way to control this weed as long as it is carried out before flowering and seed set, when weeds can also be added to home compost bins. Choose a dry day so disturbed weeds shrivel and die rather than re-rooting.

Alternatively, to prevent germination of weed seeds and smother new seedlings, apply opaque plastic sheeting or a mulch of bulky organic matter, such as woodchips, to beds at a depth of at least 8cm (3in).

Weedkiller control

In borders and vegetable patches, where the weed occurs after crops have been lifted or on bare ground, contact herbicides containing acetic acid (Weedol Gun! Fast Acting), fatty acids (SBM Solabiol Super Fast Weedkiller) or pelargonic acid (Doff 24/7 Fast Acting Weedkiller) should easily control this weed. These herbicides are non-selective and so care should be taken whilst spraying near other plants, covering these if needed during spraying with an upturned flowerpot or plastic sheeting.

Inclusion of a weedkiller product does not indicate a recommendation or endorsement by the RHS. It is a list of products currently available to the home gardener.

Download

Weedkillers for gardeners (Adobe Acrobat pdf document outlining weedkillers available to gardeners; see section 3).

Links

Chemicals: using spot and broad-scale weedkillers
Chemicals: using a sprayer
Chemicals: using safely and effectively
Weeds: non-chemical control