Bummer! So many plants have proven to be disasters for our native habitats and our gardens. I spend most of my time trying to rid this garden of Nut Sedge. Its slow progress with years of sifting earth yet to come but it is working. Bermuda Buttercups... sounds so nice but its a pretty monster overtaking coastal habitat and suburban yards here. It has tiny tiny bulbs which is crazy for a dicot. It will smother plants in Hamilton Square if we don't keep it in check. Star Thistle is marching its way ever higher along our freeways onto every little country road. No end in sight. Knapweed in Montana is another misery. Its a very small planet even for the flora! They travel the world with us. We don't use insecticides here In Hamilton Square and we have a large variety of native bees, and other insect, birds, lizards and nocturnal mammal and gophers. We will occasionally use round up to kill Bermuda Grass that invades the seems of the cemetery plots where it can't be manually be removed but we don't use it casually. Thanks for telling me about your Chasmanthe problems there. I would be very interested to see a photo of your seedlings and the flower of your Chasmanthe if you can.
