Spring Clean-up: A Toronto Master Gardener Guide

Pruning back ornamental grasses such as Miscanthus or maiden grass is tackled in spring, to make room for new, green growth. Photo: Helen Battersby

Spring clean-up is an annual event. We now know to resist the urge to clean up the garden until temperatures are consistently above 10°C or 50°F. Many butterflies, pollinators and other beneficial insects overwinter in the dead leaves and hollowed out stems of last year’s plants, and it is important not to disturb them too early in the season.

This gardening guide lists all of the activities related to cleaning garden beds and sprucing up the lawn. Gardening in the spring can be very pleasurable. It is recommended that you not attempt to complete all of this work in one day.

Cleaning Garden Beds

Matted leaves can smother your emerging plants. Clean beds by removing clumps of leaves by hand. Be careful not to damage new sprouts. However, if you have shredded your leaves the previous fall, leaf mulch left on the beds will result in organic matter being added to the soil through decomposition.

Annuals

Compost what is left of last year’s annuals. Soil from last year’s pots and planters can be used to top-dress beds, or added to the compost pile.

Perennials

Remove what’s left of last year’s top growth and seed heads. Cut back ornamental grasses in early spring as new growth appears. If last year’s growth was diseased (i.e. powdery mildew) do not put in compost. Replant any perennials that have been heaved out of the soil exposing their roots e.g. Heucheras/Coral Bells. Divide mature perennials and ornamental grasses, as needed or desired.

Woody Plants

If needed, transplant existing shrubs before they leaf out in spring. Prune shrubs to remove dead, diseased and crossed branches. To shape, cut the longest, awkward stems back to just above an outward facing bud.

If the shrub flowers in the spring, (before mid-June), prune it after it blooms. If it flowers late in the season, (after mid-June), prune it early in the spring.

To rejuvenate a mature or old shrub, remove a third of the oldest stems from the base of the plant every year for 3 years. These are usually the thickest stems. This will allow sunlight into the middle of the plant and encourage new growth. Do not remove more than 1/3 of the stems each year.

Remove and store any tree wrap/guards and burlap that were used as winter protection.

Weeding

Many weeds can be controlled during spring clean-up. They are easier to pull out when young and the soil is moist. Look for the ones that were bothersome last year. Watch for “volunteers” of desirable plants. Edit out those in the wrong place.

Mulch open soil areas using such materials as compost, shredded leaves, fine bark chips or straw to about 2 to 3 inches of thickness, to minimize the spread of weeds.

Soil Improvement

The soil in existing beds can be improved by top dressing with organic materials such as compost, shredded or composted leaves or well-rotted manure to existing beds. Spring is also the time to add slow release nutrients such as bone and bloodmeal or granular fertilizers.

Spruce Up The Lawn

Rake the lawn to remove thatch, leaves and other debris. Recutting the lawn’s edges in the spring will encourage a clean edge through the growing season. This improves the overall appearance of your lawn and helps to keep it from invading adjacent flower beds.

If you missed seeding last September, or have bare patches, spring is the second-best time to seed a lawn. Top dress with compost or purchased soil such as a triple mix (loam, peat and well-rotted manure). Keep newly seeded areas moist.

Fertilize the lawn with a balanced, slow-release fertilizer:

  • N (Nitrogen) – stimulates lush green growth of leaves and new shoots and promotes dark green colour
  • P (Phosphorus) – promotes development of strong healthy root system and setting of flower buds
  • K (Potassium) – aids in the overall strength of stems and roots and resistance to disease

Once the season has progressed far enough to require the lawn to be cut, be sure to establish good ongoing lawn care practices. Specifically, cut the grass long (at least 2 & 1/2 inches); leave clippings on; water deeply, less frequently (1 inch of water per week); and pull weeds as they appear.

Hand trim the lawn around trees; or, even better, replace the grass around trees with ground covers to avoid the risk of damaging the tree trunks while cutting the lawn. Create ditch edges or a mowing strip edge (brick or stone laid level in sand) to hold the mower wheel as you cut along the edge.

Other Considerations

As you are doing your spring cleaning in the garden, observe the microclimates in your garden or lawn area. Which areas are damp and the last to thaw? Which are in full sun, partial shade or full shade? Are there areas that retain moisture throughout the growing season? Use this information to help when you select new plants for specific growing conditions.

It may also prompt you to consider moving plants to more suitable locations. You should also consider which plants will need staking and put support in place early.

Spring is also a great time to check your tools. Clean, repair, or replace them as needed. Sharpen and clean the lawn mower.

References

Time-Life Books Inc. Complete Guide to Gardening Landscaping. New York: St. Remy Press, 1991

Hole, Lois. Lois Hole’s Perennial Favorites. Edmonton, Alberta, Canada: Lone Pine Publishing, 1995

Savvy Gardening. Spring garden clean up done right. https://savvygardening.com/spring-garden-clean-done-right/

CBC. Spring clean your garden in 8 simple steps.  Posted April 22 2018. https://www.cbc.ca/news/canada/prince-edward-island/pei-garden-spring-cleanup-8-steps-1.4626291

University of Vermont Extension. Spring in the Perennial Garden. https://pss.uvm.edu/ppp/articles/perspr.html

Hamilton Pollinator Paradise. Spring Garden Care: Four Master Gardeners Tell you how.  Posted May 11 2018. https://www.hamiltonpollinatorparadise.org/blog/spring-garden-care-four-master-gardeners-tell-you-how

Forest Preserve District of DuPage County. Slow down on spring cleaning in your garden. Posted April 9 2020.  https://www.dupageforest.org/blog/spring-cleaning-garden

Date revised: September 2021

Prepared by the Toronto Master Gardeners, these Gardening Guides provide introductory information on a variety of gardening topics.  Toronto Master Gardeners are part of a large, international volunteer community committed to providing the public with horticultural information, education and inspiration.  Our goal is to help Toronto residents use safe, effective, proven and sustainable horticultural practices to create gardens, landscapes and communities that are both vibrant and healthy.

Statement on Invasive Plants: When choosing plants, avoid invasive plants, which can spread quickly and dominate gardens.  Invasive plants are sold by nurseries, big box stores or even at community plant sales.  Invasives may already be present in your garden.  They can invade gardens by spreading from under a neighbour’s fence or may be transported by wildlife.  For beautiful, sustainable options to invasive plants, see the Ontario Invasive Plant Council’s “Grow Me Instead – Beautiful Non-Invasive Plants for your Garden” at https://www.ontarioinvasiveplants.ca/resources/grow-me-instead/ before purchasing or accepting “gifts” of plants.

Statement on Home Remedies: The Toronto Master Gardeners do not recommend home remedies, as these have not been proven effective through scientific investigation, and may even damage other living organisms in the soil or plants in your garden.  There are other garden friendly options you can use.

If you have further gardening questions, reach us at our gardening advice line 416 397 1345 or by posting your question here in the Ask a Master Gardener section.  To book Toronto Master Gardener volunteers for talks, demonstrations, advice clinics, or other services, please contact us at 416 397 1345  or bookamg@torontomastergardeners.ca.