Melia azedarach, syringa, seringa, Cape lilac, sering, maksering
Melia azedarach growing along roadside
Distinctive lilac flowers and shiny serrated green leaves
Description: Deciduous, spreading, fast-growing tree up to 20 m in height. Leaves alternate, bipinnately-compounded, margins serrated, deep green, glossy on upper surface, turn distinctive yellow in autumn; flowers profuse, lilac to purple, in large, perfumed sprays; fruits in an abundance of oblong, marble-sized yellow berries, toxic to humans but edible to birds, which spread seed widely. Planted as a garden or roadside attraction.
Origin: Asia to Australasia, the local variety being an Indian cultivar, first naturalised in Barberton in 1906 as an ornamental and shade tree. It also makes a good timber.
Occurrence: Melia azedarach is one of the most widespread of all alien invaders as it is fast growing, coppices readily and is easily germinated from dispersed seed. It is commonly found around farmsteads, along railway embankments and roads, in stream courses and on wasteland. It is a declared invader Category 3, may not be planted and must be prevented from spreading.
NB: This ‘syringa’ should not be confused with several indigenous trees that share the common name ‘syringa’ – e.g. Burkea africana (wild syringa or rooisering); Kirkia acuminata (white syringa or witsering); and Kirkia wilmsii (mountain syringa or bergsering) – and which are slow-growing, non-invasive, valuable members of our national floral population. The leaves, but not the flowers, of K. acuminata and K. wilmsii superficially resemble those of M. azedarach. If in doubt, consult a good tree book, such as Schmidt et al (2007) or van Wyk & van Wyk (1997).
Why it is a problem: It establishes itself easily, replaces indigenous vegetation, blocks waterways and can become unsightly. Flowers can be a source of respiratory irritation. The berries are one of the most common causes of human poisoning in SA and have resulted in some fatalities. Leaves, bark and flowers can also prove toxic. The tree should not be allowed to grow in proximity to small children. It multiplies readily and rapidly, even from stumps cut to ground level and burned, making physical control difficult.
Elimination / Control Methods: The species is amenable to physical and herbicidal control, but its readiness to re-grow and the propensity for seedlings to germinate once exposed to sunlight necessitates repeated attention and herbicide application.
Ring-barking or bark-stripping usually promote coppicing and development of new root suckers; this can be prevented by felling the tree below ground level – although this makes herbicidal treatment ineffective.
Several herbicides have been registered for application to M. azedarach:
- Picloram 240 g/l SL (for cut stump application): Access 240 SL (L4920)
- Clopyralid/triclopyr 90/270 g/l SL (for cut stump application: Confront 360 SL (L7314)
- Imazapyr 100 g/l SL (cut stump application): Hatchet (L7409); Chopper (L3444); Arborex (L8777)
- Fluroxypyr/picloram 80/80 g/l ME (cut stump application): Plenum 160 ME (L7702)
- Triclopyr 360 g/l SL (cut stump application): Timbrel 360 SL (L4917)
- Triclopyr (butoxy ethyl ester) 240/480 g/l EC (basal stem application): Garlon 480 EC (L4916); Ranger 240 EC (L6179); Viroaxe (L6663)
- Bromacil* 200g/kg GG (aerial or spot treatment): Bushwhacker GG (L7103)
*NB: Bromacil is known as a soil sterilant and can damage surrounding woody vegetation for many years after its application. It should only be used under the close supervision of a herbicide specialist.
NB: Follow carefully the instructions provided on herbicide label.
- All foliar herbicides require the addition of a surfactant (which includes a wetting agent), the name of the preferred one usually being given with the instructions for use;
- Others, e.g. Triclopyr, may need to be mixed with diesel;
- All herbicides should be used when freshly mixed (do not leave the solution overnight).
- Many herbicides can be toxic to other plants and or game and livestock if used inappropriately. (Mis-use of herbicides is also a criminal offence in terms of Act No. 36 of 1947).
M. azedarach in yellowish autumn foliage
ARC-LNR SAPIA News 28 (April 2013). ARC – Plant Protection Research Institute, Pretoria. www.arc.agric.za
Bromilow, Clive (2010): Problem Plants and Alien Weeds of South Africa. Briza. Pretoria
Henderson, Lesley (2001): Alien Weeds & Invasive Plants. Agricultural Research Council (ARC), Pretoria.
Schmidt, Ernst; Mervyn Lotter & Warren McCleland (2007): Trees and Shrubs of Mpumalanga and Kruger National Park (2nd Edition). Jacana, Johannesburg.
Van Wyk, Braam & Piet van Wyk (1997): Field Guide to Trees of Southern Africa. Struik, Cape Town
Van Zyl, Kathy, (compiler) (2005): Control of Unwanted Plants. Xact Information, Pretoria.
Van Zyl, Kathy (compiler) (2012): Problem Plant Control Compendium. AVCASA, Midrand
Special thanks to Dr Gerhard Verdoorn of Griffon Poison Information Centre, to Mr Ferdie Jordaan of Arysta Lifescience and to Ms Lesley Henderson of ARC for their invaluable advice and guidance. Their enthusiastic support for this voluntary project is greatly appreciated.