March Tips: The Mountain West and High Plains

As temperatures start warming up, get going with a little cleanup and planting.
Maintain your tools.

Leaf Disposal and Tool Care -- Get started on spring garden clean-up. Rake and dispose of leaves, pull obvious weeds, and spruce up hand tools and power tools.


  • Remove mulch from perennials and, especially, bulbs once they show signs of new growth.

Removing Winter Protection -- If you wrapped or otherwise provided heavy winter protection for your roses, remove it this month. Wait to remove soil from around the base until late this month or early next.


  • Cut back perennials and ornamental grasses. A power hedge clipper, if you have one, will make short work of tough grasses and woody perennials.

Pruning Trees and Shrubs -- Prune trees and prune shrubs. Be careful with flowering trees and shrubs -- you don't want to trim off developing buds. In fact, as a rule of thumb, prune flowering shrubs and trees within a month after they stop blooming.


Pruning Roses -- Prune roses this month or next once signs of growth are well underway -- the red leaf buds have started to swell and just barely unfurl.


  • Prune evergreens any time from now until late summer. (Don't prune later than that or you'll prompt new, tender growth that will get zapped by winter's cold.)
  • Prune raspberries. June-bearing types should be thinned to 6 inches apart, the tips removed, and old canes from last year removed. You can just cut ever-bearing types to the ground.
  • Be careful when working the soil this month. If it's too wet, it will dry out in hard clumps, ruining that all-important soil texture.

Planting Bare-Root Trees, Shrubs and Roses -- Plant bare-root trees and shrubs as well as bare-root roses.


When To Plant -- Plant container-grown trees, shrubs, perennial herbs, ground covers and perennial flowers as long as you're within one month of your region's last frost date. You can get a general idea by clicking on our map, but to find out precisely, give any local garden center a quick call.


  • About a month before your last average frost date, plant pots, window boxes, and containers with cool-season flowers that can withstand frost and even snow. Pansies are a favorite. Or, tuck in pots of purchased forced spring-bulbs, such as tulips or daffodils, which are available at supermarkets and garden centers now, to brighten these spots.

Start Seeds Indoors -- Start seeds indoors, if you like, early this month for warm-season annuals, such as tomatoes, marigolds, peppers, cosmos, zucchini, impatiens, salvia, basil, and others. Otherwise, wait until all chance of freezing temperatures has passed and buy established seedlings at the garden center.


  • You can plant cool-season crops now. Try seeds for radishes, peas, sweet peas, lettuces, and other greens. However, germination in wet, cold conditions can be iffy. Start seedlings indoors or buy seedlings at the garden center for more sure results, if desired. Also plant seedlings for broccoli, cauliflower, and cabbages. Wait to plant warm-season annuals (tomatoes, peppers, basil, marigolds, petunias, and the like) until all danger of frost has passed.
  • Fertilize your lawn with either an organic or a chemical product. (You can also simply rake a 1/2-inch of compost over your lawn.) This is also the time to apply a crabgrass preventer, if you choose. Check out products that combine the two, saving on application time.
  • Late this month or early next, if desired, apply a pre-emergent weed killer to beds and borders. It will greatly reduce weeds later on. However, it works by preventing seeds from germinating, so don't apply anywhere you're planting seeds.
  • Consider building a cold frame. You'll be able to plant radishes, spinach, lettuce and other cool-season crops in it this month and use it for fall planting as well.
  • Wait to do any painting on outdoor structures until the temperature has hit at least 60 degrees F. Otherwise, the paint won't last as well.