Many of the people I know spend hours and days of their lives trying to remove invasive plant species from the natural environment. As we cut, dig, burn or spray plants such as garlic mustard and European buckthorn, we curse the stupid idiots who thought it would be a good idea to allow these plants to escape into the natural environment of a country that was foreign to them.

Who would be so stupid, so thoughtless, so careless as to insert plants where there were no natural predators to keep them under control, and where they were of no benefit to native bees, birds and butterflies?

Well, it turns out that I have come close to being one of them.

It all began with good intentions, obviously. My family bought Oak Hills Farm, 100 acres of land, south of Rice Lake, between Peterborough and Port Hope in Ontario, Canada. I wanted to restore several acres to the tallgrass prairie environment that existed there before European settlement, to support local wildlife.

At that time, around 2005, there was an issue with the Karner Blue butterfly. It was threatened with extirpation in Ontario, as there were only a few isolated colonies remaining. The larva feeds on the native Sundial Lupine, Lupinus perennis. In order to increase the butterfly population more lupines were needed. So I bought seeds that were labelled as the native lupine, and planted them in various locations on my property, often on the edge of a wooded areas. They thrived, self-seeded and started spreading. Each June they would put up a beautiful display of spikes of blue flowers. A friend said they were too tall and too brightly coloured, to be the genuine native lupine, but I ignored her. Surely she was just jealous of my beautiful, big healthy plants?

Fifteen years went by until another friend also said that my lupines. pretty as they were, seemed somehow “wrong”. By now there were apps that could identify plants. I used iSeek and it identified my lupines as the large-leaved lupine (Lupinus polyphyllus), an introduced species. These plant ID apps are all very well, but they are not 100% reliable, so further evidence was needed. A quick Google search explained that it was easy to tell the difference, you just had to count the number of leaflets on the compound leaf. If it was above 7 to 11. you were looking at the large-leaved lupine, not the native sundial lupine. That was almost too easy. A quick count showed that the most common number of leaflets 14. It was one thing to ignore subjective assessments of size and depth of colour, but there was no way I could argue with basic arithmetic.

Further research revealed that cultivated large-leaved lupines can inter-breed with the native species, and that the crosses do not support Karner Blue butterflies. This was distressing, but by now there were no Karner blues left in Ontario, and attempts to preserve the species in Ontario had been abandoned. However invasive lupines ae a very problematic invasive species in some areas, such as the Mt Cook area of New Zealand, and in British Columbia, Canada.

I took one last look at my beautiful tall bright blue lupines where they extended back from the edge of some woods deeper into the shade, mixing in with other species, and noted that in one case they had also spread across a mowed path and were establishing a satellite colony on the other side. They had to go. I began by cutting all the seed heads off before they could dry out and spread. I solarised them, by putting them in a sealed plastic bag in the sunshine until I was convinced there was no possibility of them producing viable seed, then chucked the bag in landfill. Then I decided I had to proceed with step two. I put on my protective gear, loaded up my backpack sprayer with Roundup, and sprayed all the big beautiful leaves with their 14 leaflets. Within a week the lupines were dead, but I will still have to recheck for several years in case new seedling arise from seeds left in the soil.

I also have some of the lupines in a garden around my cottage, but these are separated from the wilder areas by a wide moat of turf. I think I can safely leave them, and enjoy their flowers next srpring.

I am a bit embarrassed that I made this mistake. It is always unwise to assume that plant nurseries will label things correctly. One should always confirm the ID of native plants, especially before introducing them into wild places. It took me a long time, but I have finally recognized my mistake and am taking corrective action. However, it does give me more sympathy for the farmers who were told that European buckthorn was great for making rapidly-growing thorny hedges, and with the European settlers who unwittingly brought familiar plants such as garlic mustard with them to grow in their herb garden in Canada.