Posted: 30/09/2014 at 20:44
For me alstromeria needs to ne placed carefully. I had some very good new varieties that flowered beautifully for 6 months then went dormant in midsummer creating a big space. Of course, they did spread.
I dug up every Alstromeria and kept one variety. I replanted in a more easily,isolated spot and I comtrol any spreading
Anyway, I found digging to be effective. No problems with regrowth in unwanted spaces. So, Naomi, I would continue with glyphosate but use a stronger mix.....these are available. Persistence during the entire growing season........spray all new growth seen.
Can you move valued perennials in that area? To lift and remove all traces of alstromeria roots amongst them. To continue digging thoroughly throughout the site over autumn and winter then glyphosate in the spring. I think you will win.