University of Vermont Extension 
Department of Plant and Soil Science

Spring News Article

POTTING DAHLIAS AND OTHER APRIL GARDENING TIPS

Charlie Nardozzi, Senior Horticulturist
National Gardening Association, and
Dr. Leonard Perry, Extension Professor
University of Vermont
 

Potting dahlia tubers indoors, inspecting trees and shrubs for winter injury, and cutting back ornamental grasses are some of the gardening tips for this month.

Get flowers sooner by potting up dahlia tubers and growing them indoors until it's warm enough to plant them outside. Pinch the growing tips when they get six inches tall to keep the growth short and stocky for easier transplanting into the garden.  If you stored tubers overwinter, only plant those that are not moldy or shriveled.  Keep the soil barely moist, but not wet, until growth is at least several inches tall.

It's time to start planting cole crops, such as broccoli, cabbage, and cauliflower. Get a jump on the season this month by starting them indoors in flats or cell-packs. These crops should be planted outside about two weeks before your last frost date, in soil amended with compost. Don't be concerned if the leaves turn red or purple. It's often a sign of phosphorus deficiency due to cool soils and will go away once the soil warms.

Geraniums that you overwintered indoors are probably getting tall and leggy by now. Take 4- to 6-inch cuttings, strip off the bottom set of leaves, dip the cut end in rooting hormone powder, and stick the cuttings in a pot filled with moistened potting soil. Keep the soil moist, and they should root in a few weeks.

Outdoors, remove mulches from perennials, strawberries, and bulbs. Leaving them covered too long will result in poor growth that is more vulnerable to late freezes. Removing mulch shortly after new growth has started promotes hardiness and helps the soil and foliage to dry out, avoiding diseases that thrive in wet conditions. Keep plastic sheeting or mulch handy to re-cover plants for frost protection if a late freeze is predicted.

If you left your ornamental grasses intact last fall, you can go ahead and prune them back to a height of about six to twelve inches now, higher for larger clumps.  You can use hedge shears for this, but if you have many plants you may find a weed trimmer much easier.  Prune larger grasses on a calm day, otherwise the wind may blow them all over before you get a chance to pick them up.  Remove prunings to the compost pile.

Inspect trees and shrubs for broken limbs, and prune damaged branches back to unaffected wood. In general it's a good idea to cut branches back to a branch or bud that's facing outward.  Donít leave stubs, and donít paint the cut areas.  Hire a professional to handle big jobs -- they will have the proper safety equipment.

Other gardening tips for this month include turning under winter cover crops, buying an Easter lily, fertilizing lawns, adding compost to the garden and planting peas outdoors when forsythia blooms. Visit the National Gardening Associationís web site (www.garden.org) for more information on gardening and regional reports.


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