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Margaret River Region residents are being recruited in the fight against the invasive weed Sweet Pittosporum, which threatens our iconic karri forest.

And Nature Conservation Margaret River Region (NCMRR) says the battle must now be fought in backyards and private gardens, which are spreading the seeds and reinfesting remnant bushland.

Many residents on bush blocks and rural properties have joined a groundswell of effort to combat another invasive weed – the arum lily – in recent years. But NCMRR biodiversity project officer Mike Griffiths says Sweet Pittosporum also poses a grave risk to our bushland, particularly the Nguraren Kalleep Reserve, located just north of Margaret River and formerly known as the A Class Reserve.

A native east Australian tree that grows to 12m, Sweet Pittosporum has coarse grey bark and glossy green elliptical leaves similar to bay leaves. The small, white, highly fragrant flowers occur in spring and early summer, followed by orange grape-sized fruit containing seed that are spread by birds.

“For many years, volunteers in our friends of reserves groups have been working to combat Sweet Pittosporum in Nguraren Kalleep Reserve. But we’ve identified it on private properties nearby, which pose a high risk of seeding back into the reserve and undoing the good work. So we really need locals to join the effort to control this weedy tree,” Mr Griffiths said.

“Sweet Pittosporum is so harmful because it threatens forest by outcompeting slower growing native plants. It takes over the understory and then as the plant matures it shades out the upper story too. Left unchecked, it even affects our karri forest because young karri seedlings can’t compete.”

To help local residents, NCMRR recently held a free, practical and hands-on community workshop on how to identify, remove and control Sweet Pittosporum on your property. It was hosted by bush regenerator Rick Ensley and NCMRR staff Mike Griffiths and Jodie Passmore in bushland at the end of Valley Rd, Margaret River. More workshops are planned for the future.