Striking autumn tree can make you sick

For immediate release: Friday 6 May 2005 Bay of Plenty residents are reminded to stay well away from a pretty but toxic ornamental tree that used to be a favourite with gardeners because of its stunning autumn foliage.

Environment Bay of Plenty receives several calls a year from people who have been poisoned by contact with the Rhus tree, which is still fairly common in the warmer parts of the region.

Pest plant officer Murray Severinsen says the tree’s sap can cause an allergic reaction and severe dermatitis, leading to hospitalisation in severe cases. Symptoms usually appear within one to seven days and last up to two weeks or longer. “Almost everyone is potentially at risk,” he says.

Rhus (Toxicodendron succedaneum) is a native of Japan, China and the Himalayan region. It grows from five to eight metres high and its leaves turn scarlet and crimson in autumn. For decades, it was cultivated as an ornamental tree and planted quite extensively by district councils in parks and reserves. While many trees have since been removed, both in gardens and in public places, the danger still exists for the unwary, Mr Severinsen says.

All parts of the Rhus tree are toxic and, since young leaves are easily bruised, there are more cases of Rhus-caused dermatitis in the spring than at any other time of year. “Unfortunately, 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.”

While most cases of poisoning are a result of direct contact, the resinous sap is also potentially dangerous if it gets onto shoes, clothing and garden tools. Mr Severinsen advises thorough cleaning of all contaminated items, as the resin remains active for long periods. But don’t burn the plant material, he warns, as the smoke carries particles of toxic oil. Instead, dispose of greenwaste by composting or sending it to the local refuse centre.

Rhus leaves, which are bright green above and greyish below during the summer months, are divided into four to seven opposite pairs of broadly elliptical leaflets and one terminal leaflet, each 40 to 100mm long and 20 to 30 mm wide.

Creamy white flowers are produced in spring and early summer. The fruit that develops from these hang in groups and, when ripe, are a papery pale brown berry and five to seven millimetres in diameter. They contain a single seed. The tree reproduces by seed, or suckers new stems from the roots. If you wish to control Rhus trees, contact a pest plant officer at Environment Bay of Plenty for advice first. Call 0800 ENV BOP (368 267).

ENDS

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