Chamaenerion angustifolium is a native perennial weed which spreads by seed and

Rhizomes are creeping swollen root-like structures that are actually adapted stems. Roots, stems with leaves and flowers are produced along its length. See plants such as Anemone nemorosa, bamboo, canna, border iris.

Transferring young plants from one container to a slightly larger one, where they will have more room to grow and fresh potting compost. This encourages continuous, healthy growth.

growing on

A white

Gardeners often use the word variety when referring to a specific plant, but the correct botanical term is 'cultivar'. Whichever word you use, it means a distinctive plant or plants, given a specific cultivar name and usually bred to enhance certain characteristics, such as flower or fruit size, colour, flavour or fragrance, plant size, hardiness, disease resistance, etc. Additionally, it is worth knowing that, botanically, variety has another meaning - it refers to a naturally-occurring distinct plant that only has slight differences in its looks. For example, Malva alcea var. fastigiata differs from typical plants by having an upright habit.

Rosebay willowherb is a valuable food source for numerous species of moths and butterflies; it is also a useful nectar source for pollinators, including bees.

Bees in your garden

Bees in your garden

Butterflies in your garden

Butterflies in your garden

Moths in your garden

Moths in your garden

The white or pink flowered rosebay willowherbs may be welcomed by gardeners wishing to fill large borders, but in smaller gardens some control measures may be needed. This page looks at options for gardeners when rosebay willowherb is becoming a problem. 

The RHS believes that avoiding pests, diseases and weeds by good practice in cultivation methods, cultivar selection, garden hygiene and encouraging or introducing natural enemies, should be the first line of control. If chemical controls are used, they should be used only in a minimal and highly targeted manner. 

Cultural control

Cultural methods such as hoeing and forking-out are effective against this shallow-rooted weed. Opaque mulching films can also be used to suppress its growth around woody plants or on unplanted beds.

Weedkiller control

The RHS does not support the use of weedkillers and recommends that alternative control methods are used. However, we do note that when gardeners struggle to control plants with cultural methods, regulated weedkillers/pesticides for home gardeners are available for use legally. Garden centres and large retailers selling weedkillers have trained staff who can advise on suitable products for your needs.

Weeds: non-chemical control