We have spent the last few months eradicating Allium cowanii from among our lavenders. It has been a huge undertaking and I hope and pray that it has been successful. I planted a few bulbs some years ago to provide some colour in May for our lavender border. That was a big mistake. They multiplied exponentially and began to infest the flower beds nearby. They grew in the cracks in the paving, inside the lavender plants and in the lawn. They had to go! This was not so easy. Each bulb is surrounded by a dozen or more little bulbils which drop off as you dig them up so that after many hours work weeding them up tiny green shoots appear a few weeks later from the tiny bulbs left behind. They also seed prolifically. Drastic action was called for. All the lavender plants which have looked so sensational every July had to be removed together with the crocus tomasinianus which had also seeded itself around. The whole bed was then given several doses of weed killer before being replanted.
I still love alliums but only the larger kind which if they seed do so in a genteel and modest way. Our soil is clearly perfect for them but I will be very careful in future as to which species I plant.
Well behaved Alliums Mount Everest & Gladiator
Allium cowanii bulb(s) – not recomended