I grew up in Minneapolis and have been growing native plants for about 7 years as a way to enhance my connection with the natural history of this specific place that I live. The first plants I ever grew were a few garden beans that I threw out into our front yard when I was in about 2nd grade. They grew, and I was amazed and have been enthralled with plants ever since. I have about 2 years of college behind me, no degree. I took a great Plant Propagation course at the U. of MN. a few years ago which was excellent. Observing and interacting with growing plants , especially natives, is truly inspirational to me. I don't claim to be an expert with plants, natives included, but mostly would like to encourage others to develop their own experience with these amazing transformers of solar energy.
I have been planting flats of 2" plug pots with native seeds since May 25, and some of them are sprouting. However, I have a couple decent sized (maybe 40 plus feet) Cottonwood trees within 2 houses of mine, and they started blowing their seeds around in the past week or so. They drop so much seed with its attendant fluff that it piles up in drifts like snow ! It also settles in my plug pots, and because I am diligently watering them in this droughty Spring that we're enduring here in central Minnesota, the seeds are sprouting within 4 or 5 days of settling. And this is before some of my natives sprout. So, in some cases it becomes confusing as to what might be a Cottonwood seedling and what might be a Shooting Star or an Aster seedling. In one little pot there are as many as 15 or 20 Cottonwood seedlings. Nature is abundant in this seeding thing, for certain. Now Cottonwood trees are native Minnesota plants, I will admit. But a tree this large and messy, like the fast growing but ungainly native Silver Maple, might better be left in something more near it's native habitat, which would be a river bottom, not an urban back yard. I spent 20 minutes today picking the seedlings out of just one flat of pots, and am hoping I didn't also eradicate the unsprouted desirables I planted. I will employ some kind of protective barrier for my flats next planting season, possibly window screening stretched over them to keep the Cottonwood seeds impotent. I have been using frames of 1 x 6 or 8 inch boards covered with chicken wire to foil the disruptive digging of the grey squirrels for a couple years and may augment this with the window screening. I'll post a few pictures soon to illustrate some of my struggles and solutions with these issues.