Monthly Gardening Calendar
Sharon Morrisey, Consumer Horticulture Agent
University of Wisconsin-Extension in Milwaukee Co.

March, 2006

This year, the lamb of winter was January and the lion was February.  Spring arrives theoretically on March 20^th but uncertainty is still the mindset.

As a result, do not be too hasty to get started with spring clean-up out in the yard.  Do not clear away the dried leaves and stems from the bases of your herbaceous plants until the weather has settled down and the newly emerging sprouts have adjusted a little.  Cleaning up too soon prematurely warms the soil and encourages new growth which is destined to be nipped by inevitable frosts in April. 

The only lawn care in March should be raking or core aerating.  Raking is done to clear out the zigzag meadow mouse trails and for general clean-up of leftover fall leaves, twigs and snow-matted areas.  Core aerating is helpful to smooth out lumpy lawns instead of rolling which only serves to compact the soil.  It should be done while the soil is moist but not wet and the cores should be left on top of the lawn, not removed.

Pruning is another possibility for yard care in March.  Get it all done before the plants leaf out if possible.  Fact sheets on pruning trees, shrubs and evergreens can be printed from the UW-Extension Horticulture Team website at wihort.uwex.edu.  Click on the link for the Wisconsin Garden Facts.

Use the numbers given after a calendar entry to get more information from the UW-Extension InfoSource educational phone message system. InfoSource messages for the garden calendar entries can be downloaded and printed for future reference from the website at:  inforsourc.uwex.edu.

First Week

Take bulbs out of cold storage for forcing as soon as they have had a long enough cold period.  The smaller bulbs like hyacinth and crocus only need 8 weeks of cold while tulips and daffodils need 12 - 14.  Paper white narcissus do not require this chilling so can still be purchased and potted up to grow and bloom yet this spring.

Tender bulbs of tuberous begonias, caladiums, dahlias, and canna lilies can be potted up in well-drained soil rich in organic matter.  Discard any that have rotted in storage.

If you have been storing geraniums in cool, dark conditions, its time to pot them up, cut them back and start watering again.

Cut back geraniums and coleus that you have kept growing indoors through the winter to only a few buds. This will stimulate new growth and a fuller plant by the time summer arrives.

The longer days and shorter nights now will stimulate houseplants to grow more rapidly again so you may resume fertilizing. Use fertilizers at only half-strength and only every other watering. If March is cloudy plants will still use less water and therefore less fertilizer.

Continue feeding your holiday plants like Christmas and Thanksgiving cacti, poinsettias, cyclamen, azalea and amaryllis.  After flowering they start actively growing again and therefore need more nutrients.

Second Week

The end of the dormant season is the best time to prune almost all trees and shrubs.  Pines are about the only exception.  Let their new growth expand until young needles are half of full size before pruning.

Spring flowering shrubs can be pruned now, too, unless you can't stand losing the flower buds on the stems you are removing.

Branches cut from spring flowering shrubs and fruit trees can be brought in and put in warm water to force them into bloom.

Do not use tree wound dressing or paint on pruning cuts.  These can actually slow the healing process.

Elm, maple, birch, and black walnut ooze sap when pruned in the spring due to water pressure from the moist soil.  It will not harm the plant but you can prune these in early summer or late fall instead if you are bothered by it. 

Some insect pests of trees and shrubs are best controlled by spraying with dormant oil.  This includes scale insects of pine, lilac, and euonymus and many of the gall-forming insects.  These insects reside on stems or needles and are smothered by the oil. Galls are mostly a cosmetic problem but scales can weaken plants. Check weather forecasts to be sure temperatures will stay above freezing for 8 - 12 hours after spraying to avoid damaging stems and needles.

Prune out and burn or bury the brown, shriveled "witches-brooms" on honeysuckle.  The leaf-folding aphid that causes these overwinters in these growths.  They feed on new growth as soon as the buds break in the spring.  This one is hard to control since untreated honeysuckles are everywhere.  This may be a good time to consider replacing honeysuckles with less invasive plants with fewer pest problems.

Sow seed for parsley in pots on a bright window sill.

Third Week

Make St. Patrick's Day a floral holiday with shamrocks and other assorted foliage plants.  Kids get a kick out of making their own "Irish" carnations by using white carnations and a vase of green food coloring and water.  At the same time they learn that plants suck water up and move it through the whole plant.

Start planning the vegetable garden.  Be sure to include your children or grandchildren in the process this year.

Seeds of the following annual flowers can be started indoors:  ageratum, wax begonia, browallia, dianthus and carnation, dusty miller, impatiens, larkspur, lobelia, dwarf marigold, nierembergia, pansy, petunia, moss rose, snapdragons, and stocks.  Be sure to use a sterile seed starting medium, supplemental lighting, and bottom heat for best results.  Different species also have different requirements for light or darkness during germination.  Look up the varieties you have on the seed packet, in a seed catalog or a good reference book.

Tops of onions seeded last month should be clipped to keep them at about 4 inches.  This diverts energy to bulb growth.

Fourth Week

Sow seeds indoors for the following vegetables:  broccoli, cabbage, cauliflower, celery, eggplant, and head lettuce.

Sow seeds indoors for the following flowers: alyssum, verbena, calendula, celosia, coleus, dahlia, phlox, and salvia.

Be mindful of warm days when the sun can cause heat to build-up under rose cones, cold frames, and in other plant protection systems.  However, avoid removing mulches prematurely from plants with tender new tissue forming.

Examine lawn areas where water may have pooled or snow cover lingered.  Snow mold fungus may develop in these areas.  Also look for meadow mouse tunnels in the browned grass.  Both can be improved by roughing up the affected area with a rake to encourage the adjacent healthy grass plants to fill in.

Take your lawnmower in for servicing to avoid the rush at the repair shop on that first nice weekend of April.  Get it tuned up, the oil changed, and tighten all bolts. At the very least, get the blade sharpened.

On nice days, go outside and turn the compost pile.  This will get it "cooking" again.  Hopefully, it will also help you resist the urge to start working the soil too soon.

During inclement weather, clean-up and sharpen garden tools and prepare other gardening equipment for the busy months ahead.  Inventory pesticides, fertilizers, bags of potting soil and amendments.  Finish up last years records.  And there is still time to do a little dreaming and planning.

If you need more room to garden, consider renting a 20' x 20' or 30' x 30' plot from the Milwaukee County UW-Extension's rental gardening program.  Call 414-290-2405.  In Waukesha County, the UW-Extension's rental gardening program can be reached at 262-548-7775.