Distribution of tree mallow in the UK

Distribution of tree mallow in the UK

What is tree mallow?

Tree mallow (Lavatera arborea) is hard to miss. It is a tall plant, up to 3 m high, with attractive flowers and big woolly leaves. Tree mallow is a Mediterranean-Atlantic herb of the Mallow family (Malvaceae). Tree mallow is biennial, i.e. lives for two seasons. It germinates and forms leaves in the first year and flowers and fruits in the second year before dying off.

Recognising tree mallow

Tree mallow has soft rounded velvety leaves that are 5-7 lobed and can be up to 20 cm diameter. It has woody stems that are up to 3 cm diameter and are hairy when young. The flowers are 2-5 cm across, and are lilac/pinkish-purple with broad deep dark purple veins. The flowers occur in clusters of 2-7. The dry seeded fruits are yellowish and wrinkled.

Tree mallow flower
sea
Tree mallow stems
Tree mallow flower
Single plants
Environment underneath dense tree mallow stands where little else grows other than a few tree mallow seedlings

Habitat

Tree mallow is native to the south-west and west coast of the UK (see distribution map). It is thought that its occurrence along the east coast of Britain is probably due to escapes from coastal gardens. However, it was also probably introduced to seabird islands by lighthouse keepers, as it is thought to have been used for poultices and in the preparation of ointments to heal burns. Tree mallow grows on maritime rocks, cliffs, stony ground or coastal bare ground and can form dense stands that cover large areas. It is most abundant in nutrient-enriched soils, occurring frequently in areas with large sea-bird colonies due to input on guano. The species is frost sensitive and has been restricted to mild coastal micro-climates and is predominately lowland in occurrence. However, with climate change its distribution could potentially expand.