A gift from New Zealand

Worrying signs in the dunes at the west end of Holy Island in Northumberland warn about an invasive interloper and exhort you to rid your clothing and your dogs of all traces before leaving the Island for fear of spreading it to other parts. However, once you experience for the first time the dubious pleasure of pirri-pirri bur (Acaena novazelandiae) in your socks, you soon realise that this well intentioned advice from Natural England is doomed to failure.

It looks innocuous, growing low among the dune grasses, but in the summer it throws up spherical seed heads which are fiendishly effective.

They reckon that this plant was most probably introduced to the UK from its native New Zealand on wool imports coming into nearby Berwick upon Tweed. Its hard to track down exactly when but one source I found puts it to about 1915. Its in other parts of the world now too including the US where it has the curious common names of biddy-biddy and bidgee-widgee.

In no time, I had collected the first seed head - on my shoe.

If you try to pick it off it plays its next ace. The round head disintegrates into a dozen or more separate seeds each firmly attached.


So, how does it work?


Arrow heads..... hundreds of them....

What can you say but .......brilliant (and don't take a hairy dog.)

One bizarre technique I heard about to control its spread is to drag a piece of old carpet behind a quad bike to gather up the seed heads alongside paths. Its probably easier just to get everyone to put their wellies on.