Highbush cranberry is an ornamental

Q I have heard of a plant called highbush cranberry. Does this plant really produce cranberries that you could eat?

A Highbush cranberry is a common name that's used for the viburnum species Viburnum trilobum. I prefer to use the common name "American cranberrybush viburnum," even though it's quite a mouthful.

American cranberrybush viburnum is a North American native, growing from New Brunswick to British Columbia and New York to Oregon. It is well-adapted for growing in the Upper Midwest and is winter-hardy through USDA Zone 3. This large, multistemmed shrub grows 8 to 12 feet tall with an equal width. It has attractive, three-lobed green leaves that develop nice red fall color.

American cranberrybush viburnum blooms in spring. The flat clusters of lacy white flowers are carried along the stems and are very attractive. The flowers are followed by clusters of fruit which turn bright red by early fall. The fruit usually is quite persistent, often staying on the plant all the way through winter. This makes a very colorful accent in the winter garden.

I personally prefer to admire American cranberrybush viburnum fruit rather than eat it. It is edible but is rather tart and has a somewhat acrid bite. I have seen recipes for making jelly with this fruit, but this just reinforces my belief that almost anything can be made edible if you add enough sugar. Several cultivars have been selected specifically for fruit quality; 'Wentworth' is one of these.

I certainly would recommend growing American cranberrybush viburnum as an ornamental shrub. It has multiseason interest with its flowers, foliage and fruit. Plant several as a tall, informal hedge, or as individual specimens. Then you can decide for yourself whether to eat the fruit or just admire it.

Q Can we grow peanuts in Minnesota?

A Peanuts are not grown as a commercial crop in Minnesota, but if you're feeling adventurous you could try to grow them in your home garden. Peanuts need a full four-month-long growing season and plenty of warmth, both of which are pretty hard to guarantee in Minnesota.

Peanuts, like peas and beans, are members of the legume family. They are frost-tender, warm-season annuals, completing their life cycle in one growing season. Shelled peanut kernels are seeded directly into the ground when the soil is thoroughly warmed in the spring. The peanuts grow into mounded 18-inch-tall plants that resemble clover. When the yellow flowers are fertilized, they turn down toward the ground. A structure called a peg, which looks like a thick root, then grows down from the flower to the soil. The peg works its way several inches down into the soil and one to four peanuts develop from the end of the peg. Each peanut shell usually contains two or three seeds.

To harvest peanuts, the entire plants are dug up and air-dried for a few days. Most peanuts are then roasted before being sold in the shell or used for processing. Peanuts are native to Brazil but have become a part of various cuisines around the world.

To try to grow peanuts in Minnesota you will have to try to cheat Mother Nature, and also hope that she provides a long, hot summer. The first consideration is soil type. Because of the unique way that peanuts develop they need sandy or sandy loam soil, so that the peg can readily work its way into the soil.

You probably will need to try starting the peanuts indoors in individual peat pots to get a jump on the season. You'll also need to try to get the soil outdoors warmed up sooner than normal. A raised bed will help, and covering the soil with clear plastic will help to build up some heat in the soil. Peanuts are very sensitive to frost, so don't set the plants out until we're into the frost-free days (about the third week of May in the Twin Cities area). Then cross your fingers and hope for hot weather and a long growing season. Several peanut varieties I saw listed in seed catalogs take 120 to 135 days to mature, which will be difficult to attain here. But part of the fun of gardening is experimentation, and if it works, let me know!

QI have an apple tree and two shade trees that I want to prune. I understand that winter is the time to prune, but is there any particular time during the winter? Can I start pruning now?

Late winter is an ideal time to prune trees. You can certainly start now in mid-February. March is often a good month to prune just because the average daytime temperatures have warmed, making it more comfortable to be outside.

You want to prune when the trees are still dormant; if you haven't pruned by mid-April, wait until the spring growth flush is completed before you prune. There is also some evidence that trees pruned in early winter (December-January) may lose some winter hardiness, so that's another good reason to wait until February or March.

-- Nancy Rose is a research horticulturist at the Minnesota Landscape Arboretum. She spends her spare time gardening, inside or outside, depending on the weather. Please address gardening questions to her at the Minnesota Landscape Arboretum, PO Box 39, Chanhassen MN 55317. She will answer questions in this column only.