There are any number of plants you could add to your plot, depending on the space you have. For instance, I have my roses and hydrangeas underplanted with all kinds of spring blooming bulbs. The bulbs come up and fill the space that only has empty branches in the winter and then by summer when the bushes fill in, the bulbs have gone dormant.

Daylilies are very popular among bulbs, because the day lily foliage mimics and hides the bulb foliage as it goes dormant. The only tricky part is to not damage your bulbs when it's time to dig and divide the daylilies. Still, it's a great way to fill the space throughout the year.

Ground covers are wonderful over bulbs: creeping phlox, mazus, mondo grass or liriope, just to name a few.

You could also add some summer and fall blooming bulbs to your spring bulb bed: lilies, dahlias, crocosmia, etc. I'm not really good with bulbs that grow as far north as you are, but any good bulb book could help you there.

And finally, annuals are perhaps the easiest and most versatile. Since your soil is loose and sandy, you won't have to dig very large or deep holes. Just ease your bedding plants into holes between your spring bulbs, and within a few weeks, the bed will be full of glorious color.

P.S. No matter how many plants you have in a bed, if you want to control weeds, you need to 1. Keep several inches of mulch over the whole bed (pull it a couple inches away from the crowns of your plants). And 2. Hand pull the few weeds that manage to come up through the mulch.

The first gardening book I ever read said if you can prevent any weed from making seed in your garden for three years in a row, you will have virtually no weed problems at all. I tried it, and it is absolutely true. I doubt if I spend an hour a YEAR pulling weeds, but I do bend over and pull them the very first time I notice them. It's good for the waistline too! :)

Donna I agree as far as weeding goes...weed heavily 1st year, 2nd year far less weeding, and by year 3 you just have an occasional weed. I don't weed as fastidiously as I should, but in my 12-18 month old beds, I have about 1 hour weeding a year for about 200 sf bed. The 6 month old beds (fall planted) needed about an hour each month this past year, and I expect that to significantly decrease this coming summer.

I highly recommend Shirley poppies or any annual poppy planted with bulbs. Just obtain seed, scatter before the last frost and they will bloom for the summer, make cool pods, self seed and be back for years. There are various colors and combinations available.