What does it look like?
Smilax is a scrambling or twining perennial with dense clusters of white, fleshy, tuberous roots and thin, wiry, branched green stems that can grow up to 3m long. Its oval to narrowly pointed leaf-like structures (10–35 × 4–15 mm), each with seven visible veins and appearing at every node, are actually cladodes—flattened stems that resemble leaves. From July to August, small greenish-white flowers (5–6 mm) emerge, followed by round red berries (6–10 mm) containing 2–8 tiny black seeds. The presence of large, leaf-like cladodes helps distinguish this species of Smilax from other members of the Asparagus species.
It grows at a moderate rate, with tough, long-lived tubers that resprout readily. Abundant seeds are widely dispersed, primarily by birds. The plant tolerates a range of conditions (including moderate shade to full sun, low to moderate rainfall, and exposure to salt and wind) but prefers well-drained soils. Tubers can also spread through soil and water movement. It is commonly found along roadsides, in hedgerows, and in wastelands.
Why is it a problem?
It forms dense patches and smothers low growing plants and seedlings, mostly in low canopy habitats. It can eliminate vulnerable native coastal species. It well on poor or volcanic soils, bare rock, sand, coastal and estuarine zone, bluffs, rocks.
Control methods
Physical control
Dig out tubers and dispose of them at a refuse transfer station. You can also burn or dry them and leave them where they are to rot down. Grubbing tubers can expose soil, allowing seeds to germinate. Always follow up on treated areas at least 6-monthly.
Herbicide control
Weed wipe (spring-early summer only) using 333ml glyphosate (360g /L) per 1L water, no penetrant.
Spray (spring-early summer only) using 200 ml glyphosate (360g/l) + penetrant per 10L water. Do not add penetrant when spraying against tree trunks. Spray lightly, avoiding runoff.
Tubers resprout after spraying and stems break at ground level so plants cannot be pulled out. Replant treated areas where possible after 2-3 treatments to establish dense ground cover and minimise reinvasion.
CAUTION: When using any herbicide or pesticide, PLEASE READ THE LABEL THOROUGHLY to ensure that all instructions and safety requirements are followed.
Related links
Management Programme
National Pest Plant Accord
All plants on MPI's National Pest Plant Accord (NPPA) are unwanted organisms under the Biosecurity Act 1993 whose formal or casual trade contributes significantly to their spread.
Plants on the Accord cannot legally be propagated, distributed, or sold in New Zealand. If allowed to spread further, these pest plants could seriously damage our economy and environment.
Unwanted Organism
An unwanted organism is any organism that's capable of causing harm to natural or physical resources (like forests and waterways) or human health. A number of introduced pests in New Zealand are classed as unwanted.
More informationTaxonomies
FamilyLiliaceae
TypePlants
GroupVine
HabitatLand
Management ProgrammeNational Pest Plant AccordUnwanted Organism
