Dormancy Pruning in Michigan: A Horticulturist’s Perspective

Dormancy is one of the most powerful tools Mother Nature gives us. Learning to prune during this period can transform the health, structure, and longevity of your plants. But timing matters. Not all woody plants appreciate a winter prune, but in Michigan’s climate, making the right call can mean the difference between vigorous spring growth and another season of unruly, unhealthy growth.

What is Dormancy Pruning?

Dormancy pruning simply means pruning plants during their sleep phase. Typically after leaf drop in late fall through early spring before bud break. Here in Michigan, that window usually runs from December through early April, depending on weather patterns.

Pruning during dormancy allows us to:

• Reduce spreads of disease

  A wounded plant is most vulnerable to infections and illness of any sort. Opening these injuries during wintertime helps negate the risk of spreading infections as the cold kills most pathogens. This allows for the plant to start healing as it awakens.

  
  

• See branch structure clearly, resulting in easier decision making for attractive form

  
  

• Minimize sap loss

  
  

• Stimulate strong spring growth

  Dormant pruning allows the energy a plant has to focus on the branches and buds that remain. Giving plenty of energy to encourage a more robust and healthy bloom.

  
  

• Avoid summer stress on freshly pruned plants

This Acer palmatum 'Crimson Queen' is in dormancy, which is peak time for a healthy prune. Photo by Chelsea Maylone

Plants that benefit from Dormancy Pruning

1. Trees, especially those with strong susceptibility to pest and pathogens during the growing season

• These are some of the best candidates for dormant pruning:

• Oak (Red, White, Pin Oak) – Winter pruning helps prevent oak wilt spread.

• Maple (Red, Sugar) – Best pruned in late winter to avoid heavy sap flow.

• Linden, Elm (Dutch elm disease prevention requires special timing), Ash (where healthy and minimally affected by EAB)

• Hackberry, Honeylocust, Sycamore

• Generally any tree not grown for spring flowers

Dormancy pruning helps correct structure, remove rubbing branches, and reduce hazards from snow and wind. A wounded plant is the most vulnerable to infections and illnesses of any sort. Opening these injuries in wintertime practically negates the risk of immediate infection as the cold kills most pathogens. This allows for the plant to start immediately healing in spring, when the number of bacteria is still low, and means that the wound is open for the shortest amount of time possible in the warmer weather, as the plant can start healing as soon as it awakens.

2. Fruit Trees

Michigan’s fruit-growing heritage makes this category especially important.

• Apple

• Pear

• Cherry

• Plum

• Peach (late winter only—peaches are sensitive to over-pruning)

• Dormancy pruning encourages fruiting spurs, improves air circulation, and reduces disease pressure such as fire blight in apples and pears.

An early dormant-season prune on this burning bush will show heavy regrowth starting in spring. Wait until May and the gardener is left with a sparse shrub for the rest of the year.

3. Many Common Michigan Shrubs

These woody shrubs respond very well to winter pruning:

• Dogwood (Red- and Yellow-twig)

• Spirea (summer-blooming varieties like Japanese Spirea)

• Ninebark (Unless grown for flowering - many varieties are grown for foliar color)

• SMOOTH Hydrangea (Hydrangea arborescens, e.g., ‘Annabelle’)

• Panicle Hydrangea (Hydrangea paniculata, e.g., ‘Limelight’)

• Buddleia (Butterfly bush - typically die down to a few buds)

• Cotinus (Smoke bush)

• Boxwood (Heavy thinning needed after years of shearing hedges)

• Potentilla

• Lilac —only for structural shaping when flowers can be sacrificed

Without any leaves to hide the stems, these flowers become easy to prune. This Hydrangea paniculata can be pruned very hard - simply leave a set of buds near the bottom of stems. Photo by Chelsea Maylone

4. Roses

Most shrub roses and hardy varieties (e.g., Knock Out roses) benefit from dormant pruning to remove winter die-back and encourage dense growth. Atzinger Garden typically does this in April once viable buds can be identified, but before the plant has fully leafed out.

Michigan Plants That Should NOT Be Pruned in Dormancy

Some plants are better left untouched until after they bloom or during the growing season. Pruning any of the following in winter can remove future flowers, stress the plant, or invite disease.

1. Spring-Blooming Shrubs

Prune these after they bloom, never during winter, or you will remove flower buds already set the previous fall:

• Forsythia

• Lilac (common lilac – major cuts should wait until after bloom)

• Weigela

• Mock orange

• Viburnum

• Rhododendron & Azalea

• Magnolia (tree)

2. Evergreen Trees

Avoid winter pruning on evergreens unless removing damaged or hazardous limbs:

• Pines

• Spruce

• Fir

• Hemlock

• Arborvitae

• These conifers respond best to pruning during the growing season when they can actively produce new buds or candles.

  
  

4. Bigleaf Hydrangea (Hydrangea macrophylla)

This is a major point of confusion. While it is possible to gain some blooms from new growth, most blooms come from the previous years buds.

These hydrangeas bloom on old wood and are notoriously sensitive in Michigan’s colder zones (especially 5 and 6). Winter pruning = minimal flowers.

Best Practices

Time your cuts right

Late winter (February–March) is ideal—temperatures rise enough to reduce desiccation, but buds haven't broken yet.

Sanitize tools

Especially for fruit trees and diseased wood—use 70% isopropyl alcohol between cuts.

Don’t remove more than 25–30% of a plant in one dormant season

Over-pruning weakens the plant and makes it more susceptible to stress.

Always use sharp tools

Dull shears and knives can crease stress marks and crush tissues making it difficult for branches to heal properly.

Follow other general pruning guidelines

Know the goal - Perform heading cuts to encourage growth and thinning cuts to reduce growth.

Start by removing dead, diseased, or crossing/rubbing branches

Much pruning happens by Atzinger Gardens in February and March. Key pruning techniques must be followed. Here, evidence of dull pruners used can be shown in the crushed tissues. Despite the dormant pruning timing advantage to disease resistance, pruners and saws must be sharp and sanitized.