Weed Watch – Beggars’ ticks

Beggars TickBeggars’ ticks (Bidens frondosa) is an upright annual that is usually about 20 to 60 centimeters tall – although it has been known to reach 1.8 meters at times. It usually sports reddish stems that look similar to the garden dahlia, with pretty yellow-orange, daisy-like flowers from November through May. Leaves have tooth-like edges and are grouped in 3 (or 5) leaflets at the base of opposing branches. The plant dies back in winter.

Bidens is distributed throughout the tropical and warm temperate regions of the world. Most species occur in the Americas, Africa, and Polynesia, and there are some in Europe and Asia. It has a number of common names including  beggars’ ticks, black jack, burr marigolds, cobbler’s pegs, Spanish needles, stickseeds, tickseeds and tickseed sunflowers.
Beggars’ ticks is a threat to wetlands and waterways; and in New Zealand it grows quickly pushing out existing native species, preventing new plants from establishing. It also produces barbed seeds, which are easily transported on clothing and animals, which assists with its widespread distribution.

You can spot it in damp sites such as along the sides of drains, streams, ponds, swamps, wetlands, low-lying areas and possibly even in home gardens. It has no legal control requirements but it is a weed in some situations, especially in wetland areas.
The best way to control its spread is to remove the entire plant. They are easy to pull out and the material should be disposed of. It is important to  take special care with the flower heads and seeds, as it spreads readily by seed.

It is considered a threat to areas with low stature native vegetation, and is a high priority for containment and control of new infestations.  It is difficult to eliminate from an area once it has established.

Beggars’ ticks is found in only a few locations in Canterbury, including two areas in the Te Waihora catchment – south of Charring Cross (a number of scattered sites), and the Halswell River catchment.  Control is carried out by DOC and Environment Canterbury in the Halswell catchment annually, alongside purple loosestrife control.  A surveillance programme is underway around the Te Waihora catchment to detect and prevent further spread.