Annual flowers that will seed themselves and come back each year almost as if they were perennials are highly desirable to many Minnesotans anxious to have the bounty of flowers without having to purchase new plants each season. Annuals do give the most bang for the buck as far as flower power is concerned but, given our short season, you must wait for the soil to warm enough for germination, typically around May 1. Then there is the wait until they are large enough to bloom, another 4 to 6 weeks (some even longer). That's why we northern gardeners usually buy indoor grown annuals to plant out - they will bloom earlier. Cleome (spider flower) and cosmos are beautiful annual flowers that self seed prolifically. My neighbors have to pull them out like weeds. Be careful what you wish for.
Another question on the subject of annuals that I've been asked is where to get seeds to grow the new ornamental sweet potato vines. I used to live in the South where sweet potatoes are grown to eat as well as for ornament. Never have I seen a plant bloom, much less set seed. They are regularly propagated from the tubers or "slips", little stem cuttings made from a sprouting tuber.
Since there is such a wide variety of perennials that we can grow in our gardens, there are novice gardeners who are looking for the perfect perennial. That one that blooms all summer, is maintenance free and comes in the exact color they want. The one thing that those of us who have been gardening for most of our lives know, is that there is no perfect perennial, just lots of really great ones. We also know there is no free lunch as far as maintenance goes. If we have done our homework and planted plants that are adapted to the place we put them, the work is minimal and the success maximal. As for blooming all summer like an annual would... well, here's what I had to say about that last year!
