September marks a critical transition in Ohio gardens as summer heat gives way to fall’s cooler temperatures. This timing makes it perfect for pruning many plants before winter dormancy sets in.
Proper September pruning helps strengthen plants against harsh Ohio winters, removes diseased growth, and sets the stage for vibrant spring performance. Let’s explore which plants in your Ohio garden will benefit most from your pruning shears this month.
1. Tomato Plants
The first frost typically arrives in Ohio by mid-October, making September ideal for tomato maintenance. Trim away yellowing leaves and stems to direct energy to ripening fruit.
I’ve found cutting back excessive growth helps prevent disease spread and improves air circulation. My neighbor’s unpruned tomatoes always seem to suffer more from early blight than mine.
Focus on removing suckers and lower branches that touch the soil. This late-season trim won’t encourage much new growth but will help existing fruits reach maturity before frost arrives.
2. Summer-Flowering Shrubs
Plants like hydrangeas and butterfly bushes benefit from September pruning after they’ve finished their summer show. Cutting back spent blooms prevents energy waste on seed production.
During my years gardening in Columbus, I’ve learned that moderate pruning now helps these shrubs withstand winter snow loads. Remove no more than one-third of the plant to maintain its natural shape.
Look for crossing branches that might rub against each other during winter storms. These create wounds that invite disease and pests into your prized flowering shrubs.
3. Blackberry Canes
September is perfect for blackberry maintenance in Ohio gardens. Cut out all canes that produced fruit this year – they won’t fruit again and removing them reduces disease risk.
Last fall, I skipped this chore and regretted it come spring. My patch became a tangled mess that was harder to manage and produced fewer berries than my well-pruned sections.
Thin remaining first-year canes (primocanes) to about 5-6 per square foot. This spacing allows better air circulation and sunlight penetration, resulting in healthier plants and bigger berries next summer.
4. Perennial Herbs
Woody herbs like lavender, sage, and thyme need September attention in Ohio gardens. Light pruning prevents them from becoming woody and unproductive over time.
After experimenting with different pruning times, I’ve found September cuts allow just enough regrowth before winter without stimulating tender new growth that would die in frost. Aim to remove about one-third of the current year’s growth.
For sage and thyme specifically, shaping them into slightly rounded forms helps snow slide off rather than collecting in the center and causing breakage.
5. Climbing Roses
September offers the perfect opportunity to tame those sprawling climbing roses before winter arrives. Remove completely dead canes and any showing signs of disease or pest damage.
After years of trial and error in my Cleveland garden, I’ve learned to secure remaining canes to their supports now. Winter winds can whip unsecured canes around, causing damage to both the plant and nearby structures.
Hold off on major structural pruning until spring, though. Just clean up problem areas now, removing crossing branches that rub against each other and any growth extending beyond your desired boundaries.
6. Raspberry Bushes
Ohio gardeners should approach September raspberry pruning differently based on variety. For summer-bearing types, remove canes that fruited this year while keeping the new green canes for next year’s crop.
My raspberry patch in Toledo taught me that fall-bearing varieties benefit from a different approach. You can either prune out just the tips that fruited this fall to get two smaller harvests next year, or cut everything to the ground for one larger fall harvest.
Whichever method you choose, thin remaining canes to stand about 6 inches apart. This spacing prevents the fungal diseases that plague overcrowded raspberry patches in Ohio’s humid climate.
7. Flowering Dogwood Trees
September is ideal for light maintenance pruning of dogwoods in Ohio landscapes. Focus on removing dead, diseased, or damaged branches that could become entry points for pests over winter.
When I first moved to Cincinnati, my dogwood suffered from overcrowding. Selective thinning of interior branches improved air circulation dramatically, reducing the powdery mildew issues common in Ohio’s humid climate.
Remember that dogwoods form next year’s flower buds in fall, so extensive pruning now will reduce spring blooms. Limit yourself to problem branches and save major structural pruning for just after flowering next year.
8. Ornamental Grasses
Unlike many plants, most ornamental grasses should not be cut back in September. Their dried plumes provide winter interest and habitat for beneficial insects in Ohio gardens.
However, September is perfect for removing any damaged sections and dividing overgrown clumps. I’ve found that grasses planted in my Dayton garden for more than three years often develop dead centers that benefit from division now.
Mark your calendar for February or March instead for the major cutback. Leaving the dried foliage intact provides winter protection for the crown in Ohio’s sometimes harsh winter conditions.
9. Apple Trees
September pruning helps control the size and shape of apple trees in Ohio orchards. Remove any water sprouts – those straight shoots growing straight up from branches – which steal energy without producing fruit.
After growing several varieties in my Akron backyard, I’ve learned to identify and remove branches showing signs of fire blight, a bacterial disease common in Ohio. Look for blackened, crook-shaped branch tips and cut well below the damage.
Save major structural pruning for winter dormancy, though. September cuts should focus on problem areas and minor corrections to maintain good airflow through the canopy.
10. Everblooming Roses
September deadheading extends the blooming season of roses in Ohio gardens. Cut spent flowers back to the first five-leaflet leaf to encourage more blooms before frost.
During my years maintaining the rose garden at Toledo Botanical Garden, we’d always do a light cleanup pruning in September. This included removing any diseased leaves and canes to prevent problems from overwintering.
Hold off on major cutting back until spring. Ohio winters can cause dieback on roses, so waiting to see what survived winter before heavy pruning saves you from removing healthy canes unnecessarily.
11. Blueberry Bushes
September is perfect for maintenance pruning of blueberry bushes in Ohio gardens. Remove any dead or damaged wood and branches that drag on the ground where they can pick up soil-borne diseases.
I’ve grown blueberries in my Columbus garden for years and always take time now to remove any crossed branches. These create rubbing wounds that become entry points for disease and pests over winter.
Save rejuvenation pruning for late winter when plants are fully dormant. September work should focus on cleanup and minor shaping to prepare plants for winter’s snow loads.
12. Summer-Blooming Clematis
Late-flowering clematis varieties (Group 3) benefit from September attention in Ohio gardens. These bloom on new growth, so cutting them back helps prevent the tangled mess of stems common with neglected vines.
My neighbor’s clematis always outperforms mine, and I finally learned why – she does a light trim in September to remove diseased portions and prevent winter damage from snow weight on the vines.
Don’t confuse these with spring-blooming types, which should be left alone now. If your clematis flowers in July or later, it likely falls into the category that welcomes September pruning.