Weedy bulbous plants

Diana Chapman rarebulbs@suddenlink.net
Wed, 24 Nov 2010 09:17:07 PST
Dear Jim:

>Perhaps I am needlessly paranoid about the 'Invasive Plant
 Police '<

You are not "needlessly paranoid".  Work is progressing on the government's 
proposal of a White List of approved plants.  If a plant is not on the list, 
it is automatically banned.  I was casually asked by my agricultural agent 
last year if banning Oxalis would hurt my business.  I don't think that 
question came out of the blue.  The White List proposal has been extensively 
discussed on this list, and I remember well a couple of years ago a 
representative of the USDAA saying emphatically that if a plant was weedy or 
invasive in one situation they would ban it for the entire country.  I think 
Lantana and the problems it has caused in Hawaii was cited.  When the USDAA 
gathers information, you may be certain that it will refer to this list for 
bulb information, so coupling the name of a bulb with the epithet weedy or 
invasive could be used as justification for banning it.

In this climate all kinds of things self sow with great vigor, including 
Verbascum, Verbena bonariense, feverfew, borage and virtually anything that 
produces copious seed.  Not Oxalis, though.  I used to throw my surplus 
Oxalis bulbs on the ground outside the greenhouses, where they would form 
lovely little mats throughout their first winter, never to appear again.  I 
live surrounded by pasture.  Not one garden plant has ever appeared in the 
adjacent pastures whereas they sow themselves vigorously in my garden.

We should be very, very careful in how we describe plants that make 
themselves at home in our gardens and neighborhoods.  I don't even cosider 
O. pes-caprae invasive.  I have never seen it invade pastures or natural 
areas, it is mostly present in gardens and disturbed areas in California. 
Most people don't like it because it competes visually with plants they want 
to grow.  It does not out-compete them and drive them over the brink, in 
fact it only thrives where there is little to compete with, and I speak from 
first hand experience.

A tip for dealing with aerial bulbils produced by O. convexula and others. 
Vacuum them up before they have a chance to blow around.  A small hand held 
vacuum works great.  I do this so that they don't get in the adjacent pots.


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