Wednesday wildflower: onion weed

I'm told a weed is a wildflower whose virtues have yet to be discovered.  But onion weed or three-cornered garlic (Allium triquetrum) has virtues and is still a detested weed.

The plants spread rapidly, either sexually by seeds or vegetatively by bulbs, to infest large areas.  The tiny black seeds germinate freely and get carried up on the tip of the first leaf as it grows.  The Flora of New Zealand Vol. 3 (Healy & Edgar 1980) says the first wild collection in New Zealand was made in 1928, and it was probably first introduced as a garden plant.

Allium triquetrum, onion weed.

The flowers are pretty and quite similar to those of a plant that everyone wants to grow: snowflake or Leucojum aestivum (below).  So what makes one desirable and the other an enemy of the gardener?  Well, the smell of onion weed for a start; it's garlic, but not really in a good way.  The fact it's hard to control makes it undesirable too, because it spreads and takes over wherever it lands.

Snowflake, Leucojum aestivum, a popular garden plant.

Onion weed is a close relative of those marvellous vegetables onion (Allium cepa), leek (Allium ampeloprasum var. porrum or A. porrum), garlic (Allium sativum), and chives (Allium schoenoprasum).  I understand it is edible, and at a pinch would be a substitute for garlic, but I haven't plucked up courage to try it yet.  There's enough in our garden to keep us going for a while!

Reference.

Healy, A.J., Edgar, E. 1980. Flora of New Zealand Vol. 3. Government Printer, Wellington.