Time for action on one-leaf Cape tulip

One-leaf Cape tulip is a significant agricultural and environmental weed on Kangaroo Island and landowners are required to control infestations. Action needs to be taken now for its effective control.

All parts of one-leaf Cape tulip are toxic to both sheep and cattle, although stock will avoid feeding on established plants. One-leaf Cape tulip is declared under the Natural Resources Management Act 2004 for sale and movement and sale of contaminated produce.

The weed originated from South Africa and was introduced into Australia as a garden plant around 150 years ago. It is easily recognised by its strap-like leaf and orange flowers which appear in early spring.

Its seed is spread by wind, water and in produce. Both corms and seed can be dispersed in contaminated soil or mud by various means, including by farm machinery, stock and feral pigs. Seed also can be transported in hay cut from infested paddocks, if cut after one-leaf Cape tulip set seeds (which is likely to occur between October‒November).

Control of one-leaf Cape tulip is complicated because the plant can reproduce by seed and corms. Larger infestations are best treated with herbicide applied through a weed wiper or a boom sprayer, while individual plants can be hand-wiped or spot sprayed with herbicide, or physically dug out. Slashing can be used to suppress seeds if there is no opportunity for chemical or physical control. Mature, dry stands with seed heads should not be slashed because of the risk of spreading seeds.

Natural Resources Kangaroo Island (Natural Resources KI) has two weed wipers available for loan to manage one-leaf Cape tulip in pasture and open areas. Weed wipers have proven very effective on KI and are an ideal way of controlling one-leaf Cape tulip where landholders do not want to lose valuable feed or cover. The timing of control is very critical and herbicides need to be applied before any signs of flowering for a successful bulb kill usually occurring in July and August. There are also 12 volt sprayers available for loan. These are ideal for spot spraying small patches of declared weeds before they become a much larger problem.

Natural Resources KI has produced a fact sheet and control plan for one-leaf Cape tulip and staff are available to provide landholders with advice on how and when to control one-leaf Cape tulip and other declared weeds.

Take home messages:

• if you don’t have this weed on your property — monitor for new sightings
• if you have emerging infestations — control, before it gets out of hand
• if you have established infestations — prevent spread to adjoining clean paddocks and farms. This might include spraying out buffers along water courses flowing through infested land.
• work with your neighbours to reduce its spread.

For further information please refer to the One-leaf Cape tulip Management Strategy or contact the natural resources centre.