I started to read, and I noticed the strange wording of the sentences. I think it was written first in German and then translated into English. I can still make out what it is trying to convey, but the phrasing is very awkward. Instead of saying Columbine can be invasive, it warns of a “plague” of Columbines.
The site is ad-supported and uses your cookies to target ads that you want to buy from. The ads that showed up on my page were for dolls. The first time, I clicked there were no ads, but when I revisited the page, I could see ads. I think its good to have ads rather than to be nagged to give money all the time, such as with Wikipedia.
The take away was the my Columbine can survive to 20 below zero, so it should be alright. I planted one I bought at a nursery, and since not dormant, I worry. The nights have been very cold in Ukiah. If I wait too long to set plants in the ground in the spring the hot summers will kill them off. There is nothing online I can find anywhere else to say what is the cold tolerance of Columbine. Updated: I made a mistake. The 20 below zero is on the Celsius scale, but I think it will still be ok in zone 9. If not, I learned something. It says that the plant can live for about five years. Normally, I would remove mine in the winter. When I was gardening in San Francisco, I had a lack of space, so I wanted to put in a newer plant. I am going to test this Columbine to see if can live the winter. I bought one called Aquilegia x caerulea ‘Origami White’ in 2012, and it did not live the winter. The ones I would take out were the no name Columbines because they would make too many seeds. The reason you want to remove them is they get really beat up looking in the fall.