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April 2010 Garden Calendar

Contributors: Karen Jeannette, Research Fellow and Yard and Garden News Editor; excerpts from the 2010 Minnesota Gardening Calendar.

Plant tips

soil sample.jpg
Soil sample from a shade garden area
Karen Jeannette

Prepare Your Soil

  • Find tips for fertilizing, composting, maintaining soil health, and plants for tough sites here.


Need ideas for the vegetable or edible garden?
  • Use the pre-designed veggie garden plans and participate in the MN Landscape Arboretum challenge: Veggies by the Yard.


  • Fertilize your lawn to keep it growing vigorously enough to help keep weeds out. Wait until you've had to mow it once or twice though, so you know the roots are growing actively and can make good use of the added nutrients. Seep up and reuse any granules that land on hard surfaces such as sidewalk or driveways, then water the fertilizer lightly into the soils so it "catches" and won't easily wash into storm drains when it rains.
  • If you've seen crabgrass appear early in warmer parts of your landscapes (by sidewalks, driveways, or south-facing slopes) in the past, apply a pre-emergence herbicide towards the end of April in the Twin Cities areas, a week or more later farther north. Otherwise, wait until early to mid-May to spread crabgrass preventer. Whether using a traditional product or corn gluten meal, you must water the lawn lightly afterwards to activate the herbicides ability to stop weed seeds as they sprout.

Trees, Shrubs, Flowers

Mulch used for winter protection can be
removed gradually as soil and mulch thaw
Karen Jeannette
  • Begin to remove protective cover from bulb beds, non-hardy roses and perennials in stages as soil and mulch thaw. Don't rush to uncover tender plants, though. Mulch helps prevent them from coming out of dormancy too early, when damaging cold is still a possibility. Rose canes will be okay as long as temperatures hover around twenty degrees, but most flowering perennials will die back when it's that cold.
  • Prune shrubs grown for their foliage rather than flowers, as soon as their buds swell. (Early pruning removes flower buds.) Many shrubs - dogwood, alpine currant, burning bush, and others produce tiny flowers, but they're not showy enough to worry about eliminating them. Wait to prune junipers, yews, and other evergreens until you see this year's new growth expanding. Prune forsythias, azaleas, lilacs, and other flowering shrubs only after they're finished blooming. For more about pruning flowering shrubs to maximize bloom, click here.
  • Don't prune or take care to avoid wounding oaks from April through October. April begins the period of high risk Oak Wilt susceptibility. If trees are accidentally wounded or pruning is unavoidable, cover the wounds immediately-within minutes-with one of the preferred materials such as water-based paint or shellac. For more information on Oak Wilt, click here
  • When is it safe to plant perennials and annuals? Wait until mid-to late May to plant perennials and until after your area is frost free before planting flowering most annuals.  See the MN spring frost-free map to identify when your area is likely to be frost-free. 


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