Q How late can I plant spring bulbs?
A The sooner you get them in the ground, the better.
Daffodils, hyacinths and smaller bulbs such as crocus, grape hyacinth and Siberian squill do best when you plant them by mid- to late October. Tulips tolerate late planting better, but it's still best to get them in as soon as possible.
Be sure to water the bulbs after you plant them and then about once a week until the ground freezes, unless we have regular rain. Watering is important because bulbs need to start growing roots this fall in order to make it through winter.
Once the soil freezes, mulch the bulbs with several inches of straw or leaves. Mulching helps protect bulbs from severe cold as well as from warming too rapidly in spring, which can cause bulbs to emerge too early, only to freeze when the weather turns cold again.When to cut back
Q I'm new to growing perennials and I want to do everything I can to help them make it through winter. So, should I cut them back this fall or leave them up until spring?
A If your plants look diseased or have been infested with insects, cut them down after they've been damaged by a hard frost and remove the debris from the garden. However, if your plants are healthy, it doesn't make much difference to their survival if you cut them back now or in spring.
Most gardeners are busier in spring than in fall, so getting one chore out of the way in October or November can lighten the load. If you do cut back your perennials this fall, be sure to wait until the stems and foliage are frost-damaged before trimming them to just above the ground. (As long as foliage is green, it'll continue to produce energy for the plant.)
If you prefer, you can leave healthy perennials standing all winter. The stalks will help trap snow, which in turn insulates the plants' roots. And those stalks and seedheads also add interest to the winter landscape.
When you cut plants back isn't important to their survival. Mulching is. Once the ground begins to freeze (usually sometime in November or early December in the Twin Cities), apply at least 6 inches of straw or leaves over the plants and the soil around them. That mulch will insulate the soil and roots, protecting your plants from fluctuating temperatures.
Deb Brown is a garden writer and former extension horticulturist with the University of Minnesota. To ask her a gardening question, call 612-673-7793 and leave a message. She will answer questions in this column only.