Anne Larson is a Des Moines-area horticulturist and certified landscape professional and rain garden designer. She is general manager for Garden’s Grace, Inc., a metro-Des Moines garden firm.

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Spring Garden Cleanup Yields Happy, Healthy Plants
by Anne Larson       #Fertilizing   #Landscaping   #Spring

Many weeds can germinate under the snow during the winter, so a thorough spring weeding reduces headaches throughout the gardening season.
(Photo courtesy of Agnieszka Pastuszak - Maksim,

As the last significant snow of the season nears, thoughts turn toward getting your ornamental gardens ready for the year. The tasks that need to be done include:

• Raking leaves, sticks and other garden debris out of garden beds.
• Cutting back old foliage on perennials and some shrubs.
• Digging any weeds that have begun growing over the winter.
• Pruning branches on small trees and shrubs, as needed.
• Fertilizing perennials and trees and, if desired, applying a pre-emergent weed treatment.
• Mulching and freshening your beds’ edges, as needed.
• Tools you’ll need include a fan rake, pruners or shears, tarp or organic debris bags, weeder, wheelbarrow, garden or mulch rake, spade or sidewalk edger. Debris can be composted.

A good weeding, cutting back foliage and fertilization paves the way for a colorful spring and a succession of bloom throughout the garden season.
(Photo courtesy of Barbara Helgason,

The first order of business is cutting and removing stems and stalks left behind from last year’s perennials. For most, cutting back to the base will be best. For perennials with “crowns” from which new foliage appears (e.g. Astilbe, Alchemilla, Heuchera, Geranium and Sedum), use caution. You do not want to cut into the crown. Rather, remove any winter-damaged leaves that may remain on the plants.

Ornamental grasses should be cut to 4 to 6 inches high. Siberian iris (I. siberica) is cut the same way. In both cases, watch for dead spots, which may appear in the center of the clump. That is a sign that the plant needs to be divided. Lift the plant and slice off the edges and transplant those. Discard the dead center.

Remove matted leaves, which may have accumulated in the garden over the winter. If not removed, the leaves can inhibit growth, as well as harbor insects or diseases.

Cleaning out dead limbs and leaves from shrubs is another important chore. If it is hard to get your hand into the center of the shrub to pull out leaves, a weeder can be helpful. The other important task for shrubs such as Spiraea spp., burning bush (Euonymous alata), lilac (Syringa spp.) and dogwood (Cornus stolonifera, C. sericea, C. racemosa, C. alba), is to take out old or diseased branches. This makes room for new, more productive shoots and also promotes good air circulation through the plant. This is best done when snow cover has receded but the plant is still dormant.

A good way to deal with extremely dense spirea (except weeping varieties, such as S. thumbergii) is to shear the shrub to the size of a large basketball, then gently lean on the remaining branches. The ones that snap are dead and should be raked out of the center. In the case of lilac and dogwood, remove no more than a third of larger or discolored canes each year to encourage more flowering.

Organic mulch, such as wood, compost or pine needles can really make your plant colors pop while retaining soil moisture, moderating soil temperature and reducing weeds.
(Photo courtesy of Oocoskun,


Fertilizers and Weeds
Once the perennials and shrubs have been trimmed back and cleaned up, provide fertilizer and nutrients to help the plants grow, and some type of weed control.

For insect control, hands-on weeding and scouting for bugs are effective. For weeds, there are several products on the market that suppress seed germination or root growth. Ask your local garden center what works best in your area. In all cases, make sure to read the labels and apply as recommended.

Apply fertilizer to encourage growth in perennials and shrubs. A fertilizer with balanced amounts of nitrogen (N), phosphorus (P) and potassium (K) is typically recommended, such as 12-12-12. Natural, organic fertilizers and compost will have different ratios, such as 18-0-3 or 5-2-0.

If your beds have rock mulch, your work is done. If you use wood or other organic mulches, apply after putting down your fertilizer and weed control. If your gardens have natural edges (garden bed abutting lawn), recut the edge with a spade or sidewalk edger and remove excess dirt and grass.

A thorough spring cleanup ensures that your garden gets off to a good start when rainfall is more available. It also provides a head start controlling weeds and insects. Lastly, a clean garden allows spring-blooming bulbs to have their own show.


A version of this article appeared in a March/April 2013 print edition of State-by-State Gardening.
Photography courtesy of Agnieszka Pastuszak - Maksim,, Oocoskun,, Barbara Helgason,


Posted: 02/24/17   RSS | Print


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bonnielou - 03/25/2017

Last year I had my front re-landscaped.  I have several new perennials that I am unsure whether to cut back or to let be.  The perennials in question are Goblin blanket flower, and lavender.  When I had a fall clean-up done by a professional, they left them for the winter.  Do I cut them back now that it is spring?

Thank you for your assistance.

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Jo Ellen Meyers Sharp (Zone 6a) - 03/28/2017

Thanks for writing State-by-State Gardening. The Goblin blanket flower and lavender can be cut back now. Cut the blanket flower back to the ground. Cut the lavender back to where you see greenish new grown, or about four inches from the ground. Hope this helps.

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bonnielou - 03/29/2017

Thank you Jo Ellen!

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