I used to think any time was a good time to prune—until I made a few mistakes in my Illinois garden. Some plants really hate being cut back in late summer and can struggle come fall.
But others? They actually benefit from a little cleanup right now. I’ve learned which ones to leave alone and which ones to tidy up for a healthier season ahead.
If you’re reaching for the shears this month, here’s what to skip and what to trim.
1. Hydrangeas
Hold off on cutting back those beautiful hydrangea bushes across Illinois yards! They’ve already set their flower buds for next season on old wood. Pruning now removes next year’s blooms entirely.
Wait until after flowering next summer to shape these beauties. Many Illinois gardeners make this mistake and wonder why they get leafy bushes with no flowers the following year.
2. Lilacs
These fragrant favorites have already formed next year’s flower buds in Illinois gardens. Cutting them back now means sacrificing those sweet-smelling spring blooms everyone loves.
The best time to prune lilacs is right after they finish flowering in late spring. Illinois gardeners should focus on removing dead wood only if absolutely necessary this month.
3. Azaleas
These spring-flowering shrubs have already set their buds for next year throughout Illinois landscapes. Taking pruners to them now would remove those flower buds completely.
Wait until just after they finish blooming next spring for any major pruning work. Many Illinois homes feature these colorful shrubs, and timing pruning correctly keeps them looking their best.
4. Forsythia
Those bright yellow harbingers of spring have already formed their flower buds on last season’s growth. Pruning forsythia now in your Illinois garden means cutting off next spring’s cheerful display.
Hold off until immediately after flowering next spring for any major cutting back. Many Illinois homeowners enjoy these as one of the first bursts of color after winter.
5. Rhododendrons
Like their cousins the azaleas, rhododendrons have already set their flower buds for next spring in Illinois gardens. Pruning now would remove those gorgeous blooms before they have a chance to open.
Save your pruning energy for right after flowering next year. These acid-loving shrubs thrive in many Illinois landscapes when given proper care and pruning timing.
6. Magnolias
These stunning flowering trees have already formed their flower buds for next spring throughout Illinois. Pruning now would remove those spectacular blooms before they have a chance to unfurl.
Wait until after flowering next year for any needed pruning. Illinois gardeners treasure these early-blooming trees as one of the first signs that winter is truly over.
7. Oak Trees
Pruning oaks during warm months in Illinois can spread deadly oak wilt disease. The beetles that carry this fatal disease are attracted to fresh pruning wounds and are active now.
Wait for the coldest winter months (December-February) when the beetles are dormant. Oak wilt has devastated many Illinois communities’ tree canopies, so timing pruning correctly is crucial.
8. Flowering Cherries
These showstopping spring bloomers have already formed their flower buds for next year in Illinois landscapes. Pruning now removes those buds and diminishes next spring’s display.
Hold off until immediately after flowering next spring for any necessary pruning. Many Illinois parks and neighborhoods feature these trees as spectacular spring attractions.
9. Redbuds
Illinois’ native redbud trees have already set their flower buds for next spring’s display. Pruning now would remove those stunning pink-purple blooms that emerge directly from branches.
Wait until after flowering next spring for any major pruning work. These understory trees are beloved throughout Illinois for their early spring color and heart-shaped leaves.
10. Weigela
These spring-flowering shrubs have already formed next year’s flower buds on old wood in Illinois gardens. Pruning now would significantly reduce next spring’s trumpet-shaped blooms.
Save your pruning for right after flowering next year. Many Illinois gardeners appreciate these easy-care shrubs for attracting hummingbirds and providing reliable spring color.
11. Rose of Sharon
Unlike many flowering shrubs, Rose of Sharon blooms on new growth in Illinois gardens. This makes fall the perfect time for pruning without sacrificing next year’s flowers.
Remove dead or crossing branches and shape as needed now. Throughout Illinois, these late-summer bloomers provide valuable color when many other flowering shrubs have finished their show.
12. Butterfly Bush
Fall is an excellent time to prune butterfly bushes in Illinois gardens. These fast-growing shrubs bloom on new wood, so cutting them back now won’t affect next year’s flowers.
Trim them down by about one-third their size to prevent winter damage. Many Illinois gardeners appreciate how these drought-tolerant shrubs attract pollinators all summer long.
13. Panicle Hydrangeas
Unlike their mophead cousins, panicle hydrangeas like ‘Limelight’ bloom on new wood, making fall an ideal pruning time in Illinois. Cut them back by one-third to improve structure and flowering.
These sturdy shrubs can handle Illinois’ harsh winters even after pruning. Many gardeners throughout the state love these low-maintenance hydrangeas for their reliable blooms and fall color.
14. Roses
Most modern roses benefit from fall pruning in Illinois gardens. Remove dead or diseased canes and cut back by about one-third to prevent winter wind damage.
Don’t prune too severely – save major cutbacks for spring. Illinois rose growers know that proper fall maintenance helps these beauties survive our challenging Midwest winters with minimal dieback.
15. Raspberries
Fall-bearing raspberries can be pruned completely to the ground after harvest in Illinois gardens. This simple approach removes disease potential and promotes better fruiting next year.
For summer-bearing varieties, remove only the canes that fruited this year. Many Illinois gardeners enjoy these easy-to-grow berries that thrive despite our challenging weather patterns.
16. Clematis (Group 3)
Late-flowering clematis varieties (Group 3) bloom on new growth and benefit from fall pruning in Illinois gardens. Cut these vigorous climbers back to about 12 inches from the ground.
This prevents tangling and promotes better flowering next summer. Many Illinois gardeners appreciate how these versatile vines can cover fences, trellises, and arbors with minimal care.
17. Spirea (Summer-Flowering)
Summer-flowering spireas like ‘Gold Mound’ and ‘Anthony Waterer’ bloom on new growth, making fall the perfect pruning time in Illinois. Cut them back by one-third to maintain shape and vigor.
This rejuvenation prevents these spireas from becoming woody and promotes better flowering. Throughout Illinois, these hardy shrubs provide reliable color and attract beneficial pollinators.
18. Caryopteris
Also called blue mist shrub, caryopteris blooms on new growth and benefits from fall pruning in Illinois gardens. Cut back by one-third to maintain a compact shape and prevent winter damage.
These late-summer bloomers are drought-tolerant once established in Illinois landscapes. Many gardeners appreciate their blue flowers when few other shrubs are blooming in late summer.
19. Red-Twig Dogwood
Fall is perfect for pruning red-twig dogwoods in Illinois landscapes. The youngest stems display the brightest winter color, so removing older, grayer branches improves their winter show.
Cut about one-third of the oldest stems to ground level each year. Many Illinois gardeners rely on these native shrubs for winter interest when the landscape is otherwise dormant.
20. Ninebark
This native shrub responds well to fall pruning in Illinois gardens. Cutting back by one-third maintains its shape and promotes more vibrant foliage next year.
Remove any dead or crossing branches for better air circulation. Throughout Illinois, ninebarks are becoming increasingly popular for their colorful foliage, drought tolerance, and four-season interest.