Sycamores are large invasive trees that grow quickly and can outcompete native plants. Sycamores invade forests and shrublands, short tussock lands, fernlands, river systems and bare land. They can tolerate a wide range of conditions and form thick stands of trees that stop other species from growing. Sycamores produce many long-lived seeds that can be easily dispersed by wind or water.

• Size: A deciduous tree with smooth, grey bark and can grow up to 35 metres tall.
• Leaves: Hairless green shoots with five-lobed leaves that are in opposite pairs on reddish stems.
• Flowers: Narrow, drooping clusters of thick green flowers, followed by reddish, winged ‘helicopter’ seed capsules containing two seeds.
• Root system: Roots often grow close to the surface. Older trees develop a long taproot, from which other roots sprout. 
• Habitat: Includes forests, shrublands, short tussock lands, fernlands, river systems and bare land.

Sycamores can be spotted year-round or when they flower in early spring (October-November).

To prevent or improve on damage to indigenous ecosystems, sycamore is in the site-led programme of the Otago Regional Pest Management Plan (2019-2029). The Dunedin site-led areas include Otago Peninsula, West Harbour (Mt Cargill, Quarantine Island and Goat Island). There are no specific rules associated with site-led pest plants in the plan.

ORC will take a lead role in supporting the goals of community groups and agencies in the site-led areas in relation to sycamore. This may be through advice, education, funding, service delivery or requiring other landowners to undertake control when needed.

Physical control:

• Dig out small patches of sycamores and dispose of them at green-waste transfer stations.

Chemical control:

• In summer or autumn, drill a hole every 100 mm around the trunk and fill or saturate each hole with a suitable herbicide containing metsulfuron-methyl, glyphosate or picloram gel.
• Cut the trunk near to the ground in summer or autumn and swab the freshly cut stump with a suitable herbicide containing metsulfuron-methyl, picloram and triclopyr or picloram gel.
• Spray foliage at the full leaf stage using a suitable herbicide containing metsulfuron-methyl.
• Follow up treated areas several times a year and re-treat as necessary.
• Encourage native plant regeneration or replant with natives to minimise reinvasion.

Caution: When using any herbicide or pesticide PLEASE READ THE LABEL THOROUGHLY to ensure that all instructions and safety requirements are followed.

Disclaimer: Mention of product trade names does not endorse these products nor imply criticism of similar products not mentioned. The Otago Regional Council does not give any warranty that the information is accurate or complete or that it is suitable for all circumstances.

www.orc.govt.nz/sycamore