Rhus; Japanese wax-tree
|Botanical Name||Toxicodendron succedaneum|
|Origin||Japan, China and the Himalayan region|
IdentificationRhus is a woody deciduous shrub or small tree, 5 to 8m high. The single erect trunk and branches are grey-brown. Over the summer months the leaves of Rhus are bright green above and greyish below, changing to brilliant scarlet and crimson in autumn. They are divided into 4 to 7 opposite pairs of broadly elliptical leaflets and one terminal leaflet, each 40 to 100mm long and 20 to 30 mm wide. Clusters of inconspicuous yellowish green flowers are produced in spring and early summer. The fruits that develops from these, hang in groups and when ripe are a papery pale brown berry, 5 to 7mm in diameter containing a single seed.
HabitatsRhus prefers full sun on well drained soils but will adapt to most soil types. Rhus has been widely cultivated as an ornamental plant and can now be found in most warm, temperate areas of the world. Over the years Rhus has been planted in gardens and on roadsides because of its beautiful autumn foliage
Impact to Biota and EcosystemsThe botanical name is very descriptive of the Rhus tree; Toxicodendron combines the Greek toksikos, meaning toxic with dendron, a tree, and hence poisonous tree. Succedaneum is from the Latin succedaneas, meaning following or happening later and probably refers to the possible delayed allergenic response after contact with the sap. Rhus can cause an allergic reaction and severe dermatitis from the allergen urushiol; almost everyone is potentially at risk. Symptoms usually appear within 1 to 7 days and can last for up to 2 weeks or longer. Merely contacting the leaves may cause a severe allergic reaction which may result in hospitalisation and in severe cases may be life threatening. There may be no significant symptoms after first contact, as individuals are not born allergic to Rhus, sensitivity develops after the first contact and with each subsequent contact the reaction worsens.
Dispersal Routes, Vectors, Infestation SourcesRhus reproduces by seed or suckers
Physical control is not recommended because of the likelihood of an allergic reaction. If removal is essential, carry out control after leaf fall or after the tree has been killed with herbicide. Wear protective clothing.
Mechanical removal may be an option. Remove as much of the root system as possible to prevent suckering
Any plant material should be disposed of by burying or sending to the local refuse centre. Do not burn Rhus as the smoke carries particles of toxic oil, which are particularly dangerous in this form.
|Chemical Control||Make several rows of downward cuts around the trunk and fill with neat Glyphosate. Ensure that you are protected from flying pieces of bark or sap when making the cuts|