Weedkiller tends to roll off the leaves of most bulbs. You need to mix the weedkiller with a little liquid soap to make it stick, then spray every one you can see, taking care not to get the spray on other plants of course. You are in for the long haul, if it is anything like Nectaroscordum siculum.

Do you find Nectaroscordum invasive? I planted some one year, they flowered and never reappeared. Perhaps I was just lucky... ;-)

It grows well in wet areas like river banks and meadows and is invasive

It seems that some plants in some gardens are thuggish and in others pussy cats. You can't tell until it dawns on you that you have a thug on board, then you have a fight on your hands. My Nectaroscordum do spread but not as rampant as Corydalis Lutea and that evil little Allium I have blogged about. I am inundated with V. Bonariensis seedlings this year but I like them....so far.

I do so agree, but VB never spreads for me so I love it, but I did get rid of the little white Allium - Neapolitanum,after you said how invasive it was and you were right to warn me, loads of new tiny bulbs and only planted last autumn.