Weedbusters
The bad asparagus family member
Location: nationwide and spreading fast, but a serious problem in the North Island, especially the northern half, and in the South Island in Canterbury and Nelson. Distinctive features: greenish-white flowers from July to August, followed by round red berries. Why is it weedy: spread by birds that eat its bright red berries that contain the seeds, infiltrates forest remnants, taking over shady spots, smothers hedges in farm areas, and seems to love living on the coast.
It may look delicate, but smilax is one tough customer. It has a really strong tuberous root system which is long-lived and can survive adverse conditions, resprouting easily, and spreading through soil or water. It also has strong, wiry stems that twine around anything it comes in contact with, spreading for up to 3m.
It yellows off during the time when it produces berries, making it look like it has been sprayed, but soon bounces back with a vengeance, turning lush and green again.
Smilax is often found in waste areas and on roadsides but has also invaded important wild habitats including volcanic areas, coastal and estuarine zones, bluffs, pohutukawa forest and inshore islands, where it is capable of eliminating vulnerable native coastal species.
HOW TO KILL SMILAX
1. Dig out tubers. Dispose of them at a refuse transfer station or burn them. Leave on site to rot down.
2. Weed wipe (spring-early summer only): glyphosate (333ml /L), no penetrant.
3. Spray (spring-early summer only): glyphosate (20ml /L + penetrant). Do not add penetrant when spraying against tree trunks. Spray lightly, avoiding runoff.
WARNING: THIS IS ONE VERY PERSISTENT WEED
• Tubers resprout after spraying so you need to maintain a rolling front of control – follow up on treated areas at least 6-monthly. • Stems break at ground level so plants cannot be pulled out. • Grubbing tubers can expose soil, allowing seeds to germinate. • Replant treated areas where possible after 2-3 treatments to establish dense ground cover and minimise reinvasion.