Caltrop (Tribulus terrestrilus) can also be called bindi eye, GG’s, Cats head.
Removing Caltrop seeds and seedlings, an obligate summer grower in the Swan Valley Wine Region of Perth, Western Australia. It generally appears after summer rains as a pioneering species that loves bare soil. In some years it is really bad, in others it will not be seen. There are also several similar native species, but these generally have less spiny fruits.
Eradication is essential, and vigilance against introduction is critical.
Readily controlled by herbicides in most situations, a few other pasture plants are alive at the same time, and selective control is easy in lawns and grass pasture. It generally grows too low to mow but could be controlled by solarising.
How to get rid of caltrop weed and seeds
Caltrop weed ( cow trop weed) is definitely a plant against which an eradication campaign is worth mounting. Incidentally, the original caltrop was a weapon of war – an iron device with four tetrahedral prongs that were strewn in the path of enemy horses. Whichever way it fell, one prong was always upright, ready to lame the horse.
Charming – but walk on the plant with bare feet and you will agree that it has been well named!
Caltrop seeds in an Organic Vineyard.
Occasionally, Duncan finds some caltrop seeds and seedlings in the vineyard. It grows after summer rains and we have had a few showers this year.
In row three in the shiraz plantings, right in the middle of the row, was a larger plant 800mm in diameter, with lots of dried seeds besides some 20 other smaller plants.
What is an organic vigneron to do? He can not use herbicide!
A wheelbarrow, a pair of snips and a dustpan and broom are all required besides some patience. Watch the video to get a better idea of what we do.
Firstly, spot the bright verdant green caltrop plant in the late afternoon sun. Using the snips cut the taproot, then lift the plant carefully and remove it into the wheelbarrow. Then, with the dustpan and broom sweep up all the loose sand and seeds from the plant area. Most dried seeds are within a hand span of the crown.
The removing caltrop seedlings are nearly done.
Next is the hard part, walk all the rows to check for other plants, then return in two weeks to check for new plants again before the Autumn rains.
Removing Caltrop Seedlings is a link to the video above.
You may ask, what do you do with the contents of the wheelbarrow? Duncan puts it in the waste bin for the local tip to compost it. Once he tried to burn the plants. The local authorities saw the smoke and believed that a conflagration was occurring.