Where is it originally from?
Central Europe and Western Asia
What does it look like?
Deciduous tree (<20 m tall) with smooth grey bark and hairless green shoots. Large buds (<5cm long) have pinkish inner scales. Bluish-green 5-lobed leaves (8-14 x 10-20cm) are in opposite pairs on reddish stems. Flowerheads (Oct-Nov) are narrow drooping clusters (5-15 cm long) of many dense, green flowers (2-4mm long), followed by reddish, winged, ?helicopter? seed capsules (2-4 cm long) containing two seeds (5-10 mm long).
Are there any similar species?
Maple similar, but seeds are green ripening brown.
Why is it weedy?
Long-lived, forms dense (often pure) stands. Produces many, long-lived, well dispersed seeds. Seedlings shade tolerant. Tolerates warm to very cold, moist to dry, most soils, wind, salt. Possibly able to release toxins into the soil to stop other plants growing near it.
How does it spread?
Wind, occasionally water movement. Plantations, hedges, gardens, waste places.
What damage does it do?
Forms dense (occasionally pure) stands, prevents recruitment.
Which habitats is it likely to invade?
Disturbed and intact forest and shrubland, short tussockland, fernland, river systems, bare land.
What can I do to get rid of it?
1. Dig out small patches (all year round): dispose of at refuse transfer station, burn or bury.
2. Bore and fill (summer-autumn): make 1 hole every 100 mm around the trunk and fill or saturate each hole with 2g metsulfuron-methyl 600g/kg or 1.5ml glyphosate (undiluted) or 5g picloram gel.
3. Cut trunk and paint stump (summer-autumn): cut trunk near to the ground, and swab freshly cut stump with metsulfuron-methyl 600g/kg (5g/L) or a product containing 100g picloram+300g triclopyr/L (50ml/L) or picloram gel.
4. Overall spray (full leaf stage only): metsulfuron-methyl 600g/kg (5g/L).
What can I do to stop it coming back?
Follow up 6-monthly for at least 2 years before replanting bared sites to minimise seedling regrowth