Mistletoe (Viscum album) was included in the London Biodiversity Audit on the basis of its rarity, cultural value and ease of monitoring. Though London is outside its stronghold areas in the south-west midlands, the species has many cultural links to the capital. It may never have been very common here but it has a long history in herbal medicine and seasonal traditions.

Mistletoe is a parasitic plant of deciduous trees that produces milk-white berries. Its London sites are mostly in open landscape habitats, such as trees in parks, gardens and streets.

Mistletoe’s status in London today is reasonably well-known, though many sightings need further study and confirmation. The national mistletoe survey run by Plantlife and the Botanical Society of the British Isles (BSBI) in the 1990s provided a lot of new data (Briggs 1995 & 1999).

The species is scarce in the Greater London area. A large number of boroughs have good or reasonably reliable records of the plant, but in most there are only a handful of records – sometimes just one plant per borough. The full list includes Barnet, Bexley, Bromley, Croydon, Harrow, Ealing, Enfield, Greenwich, Haringey, Hillingdon, Hounslow, Kingston, Lambeth, Merton, Redbridge, Richmond, Sutton, Wandsworth and Westminster. The most central records are in Lambeth (a single plant on a maple tree) and in Westminster (a single plant on an ornamental Malus tree).

Most mistletoe in London today grows in man-made habitats – little suitable natural habitat occurs – and the vast majority of London records are from trees in parks and gardens. Elsewhere in the country the plant also grows on trees in orchards, hedgerows, churchyards, cemeteries and linear features such as watersides and roadsides. London’s principle stronghold seems to be in the Bushy Park and Hampton Court areas of Richmond.

The main host trees for mistletoe in urban areas are cultivated apples, hybrid Limes, hawthorn, hybrid poplars, maples, willows and false acacia. Many other tree species can also be hosts. The parasitic mistletoe is, in turn, host to four species of specialist mistletoe-dependant insects. The current status of these insects in London is unknown.

There appears to be potential for more mistletoe in London – there are many suitable host trees in many suitable habitats such as parks, gardens, small estates, nature reserves and roadsides. Some of the populations in parks and estates may be relics of populations established by herbalists.

Studies of mistletoe in other cities may help our understanding of the plant in London. The best British city for mistletoe, based on the findings of the national survey, is probably Cheltenham. There has been recent research in mainland Europe.

There is neglect of some mistletoe colonies and possibly a loss of management techniques. For example, traditional ‘sustainable’ harvesting, which controlled infestations whilst allowing their survival, may be no longer practised.

Mistletoe ‘rustling’ may be on the increase because of its seasonal value.

Mistletoe may be omitted from otherwise suitable habitat creation schemes – for example community orchard schemes

Mistletoe receives the same protection as all other wild plants in the UK through the Wildlife and Countryside Act (1981, as amended). Therefore, it may not be uprooted (which would include pulling down whole plants) without the permission of the landowner. The felling of host trees may be prevented by Tree Preservation Orders.

The national mistletoe survey in the 1990s (Briggs 1995 & 1999) raised the plant’s profile significantly and gave rise to much public interest. This survey, though complete, still continues informally. It is largely concerned with data gathering.

Various campaigns promoting conservation of traditional orchards (eg Common Ground’s projects) or conservation of parkland and veteran trees may be indirectly helping mistletoe.