October marks a crucial transition in Illinois gardens as plants prepare for winter’s chill. Taking time now to cut back certain plants helps prevent disease, encourages stronger spring growth, and keeps your garden tidy through the snowy months.
Grab your pruning shears and garden gloves – your outdoor space will thank you for these timely trims!
1. Peonies Need A Clean Slate
Fall is prime time to remove peony foliage right down to the ground. Cutting these beauties back helps prevent diseases like botrytis blight from overwintering in old leaves and stems.
Many gardeners mark the location of their peonies with small stakes before cutting, making them easier to find next spring. Leave no more than 2 inches of stem above soil level for best results.
2. Hostas Go Dormant Gracefully
Once frost turns hosta leaves mushy and yellow, it’s time for their annual haircut. Grab the foliage at its base and snip cleanly with sharp shears, removing all leaves and flower stalks.
Leaving decaying hosta foliage creates perfect hiding spots for slugs and snails to lay eggs. A thorough cleanup now means fewer pest problems next year when new growth emerges from the soil.
3. Daylilies Benefit From Tidying
Daylily foliage turns scraggly and brown by mid-October in most Illinois gardens. Cut all leaves back to about 6 inches from the ground, removing any seed pods and flower stalks completely.
The crown of the plant should remain visible just above soil level. Some gardeners in northern Illinois prefer cutting daylilies even shorter to prevent snow damage, while southern Illinois gardeners might leave slightly more foliage intact.
4. Bee Balm Needs A Reset
Mildew-prone bee balm benefits greatly from October cutbacks. Trim all stems to about 2 inches above the soil line, discarding the cuttings rather than composting them if they show signs of powdery mildew.
Removing old bee balm growth improves air circulation and reduces disease pressure for next year. Many Illinois gardeners find that their bee balm grows more vigorously after a thorough fall pruning session.
5. Coneflowers: Save Some, Cut Some
Purple coneflowers present a gardener’s dilemma in fall. Their seedheads feed hungry birds, but leaving all stems standing can spread disease.
A smart compromise is cutting back about two-thirds of your coneflower stems to ground level, leaving the strongest stems with the best seedheads for winter bird feeding. Come early spring, trim those remaining stems before new growth begins.
6. Iris Foliage Harbors Trouble
Bearded iris leaves become hiding places for iris borers if left standing through winter. Cut all iris foliage to about 4-6 inches tall, creating a fan shape rather than flat-topping them.
While trimming, remove any soft or mushy rhizomes and check for borer damage. Healthy rhizomes should feel firm. October is also perfect timing to divide overcrowded iris clumps in Illinois gardens.
7. Black-Eyed Susans Need Attention
Rudbeckia often develops unsightly black spot and powdery mildew by October. Cut infected plants back to ground level, disposing of debris in the trash rather than your compost pile.
For healthier specimens, you might leave a few sturdy stems with seedheads standing for birds. The plant’s basal rosette of leaves can remain through winter in milder parts of Illinois, providing some protection for the crown.
8. Ornamental Grasses: Wait Or Cut?
Maiden grass, switchgrass, and other tall ornamental grasses add winter interest but eventually need cutting. If you prefer tidiness, October is fine for cutting them back to 6-10 inches tall.
Many Illinois gardeners delay this task until February, enjoying the winter silhouettes and rustling sounds. When cutting grasses, bundle stems with twine first to prevent a messy scatter. Sharp hedge shears or a powered hedge trimmer works best.
9. Asparagus Ferns Signal Harvest’s End
Once asparagus ferns turn yellow and brown, it’s time for removal. Cut all stems at ground level after the first hard frost, typically by late October in most Illinois regions.
Cleaning up asparagus beds helps prevent fungal diseases and asparagus beetles from overwintering. After cutting, apply a layer of compost around the crowns but not directly on them. Some gardeners mark row locations with stakes before winter arrives.
10. Phlox Cleanup Prevents Problems
Garden phlox often suffers from powdery mildew by season’s end. Cut all stems down to about 1-2 inches above soil level, removing and disposing of all foliage rather than composting it.
A thorough fall cleanup dramatically reduces next year’s mildew issues. While cutting back, check for any crown rot and improve drainage around plants if needed. Healthy phlox crowns should be firm and whitish-green.
11. Clematis Varieties Need Different Approaches
Knowing your clematis type determines October pruning. Group 3 clematis (sweet autumn and Jackmanii types) can be cut to 12 inches tall now, while Groups 1 and 2 need minimal trimming.
When in doubt, simply remove dead and damaged vines, saving major pruning for spring. Mark your calendar for next year with specific pruning times based on your clematis variety. Illinois winters can damage clematis left completely unpruned.
12. Hollyhocks Harbor Rust Disease
Hollyhock leaves typically show orange rust spots by October. Cut all stems to ground level, carefully bagging and disposing of all foliage to prevent rust spores from overwintering.
The rosettes of new leaves at the base can remain if they appear healthy. Improving air circulation by thinning plants and applying fresh mulch around (not on) the crowns helps reduce next year’s rust problems in Illinois gardens.
13. Vegetable Garden Tomato Cleanup
Frost-blackened tomato plants need complete removal from Illinois gardens by mid-October. Pull entire plants, including roots, cutting larger plants into manageable pieces for disposal.
Never compost tomato debris as it often harbors late blight and other pathogens. After removal, consider planting a cover crop like winter rye in the empty bed. Rotating next year’s tomato location reduces disease buildup in the soil.
14. Rhubarb Leaves Turn Toxic
Rhubarb leaves naturally die back after frost, creating a soggy mess. Cut all leaves off at the base, leaving the crown exposed. Always dispose of rhubarb foliage in the trash, never the compost pile, as the leaves contain toxic oxalic acid.
After cleanup, apply a 2-inch layer of compost or well-rotted manure around (not covering) the crown. This feeding helps fuel next spring’s growth in Illinois gardens.