To Prune or Not to Prune
General Rule: October is for clean up rather than shaping. Save structural pruning for late winter!
Prune in October
Peonies: Cut to the ground after frost; discard foliage to reduce botrytis.
Bee balm (with powdery mildew): Discard infected foliage so spores don't overwinter.
Phlox (with powdery mildew): Discard infected foliage so spores don't overwinter.
Iris (with leaf spot): Remove spotted leaves and borer-damaged foliage.
Hostas: Cut back once foliage collapses after frost.
Daylilies: Cut back once foliage yellows.
Summer-bearing raspberries & blackberries: Remove the spent canes that fruited this year.
Asparagus: Cut ferns once they turn brown.
Prune Late Winter (Feb-early March)
Roses: Main pruning in late winter; in fall only remove dead/diseased canes
Apple, pear, peach, plum: Prune while dormant.
Grapes: Prune while dormant.
Crape myrtle: Thin rather than top; topping weakens the plant.
Panicle hydrangea (e.g., Limelight): Blooms on new wood.
Smooth hydrangea (e.g., Annabelle): Blooms on new wood.
Butterfly bush: Hard fall cuts raise winter damage risk.
Ornamental grasses: Leave for winter interest and crown protection.
Lavender, rosemary, sage: Light tidy only; avoid cutting into old wood.
Boxwood, holly & other evergreens: Shape in late winter; a light holiday trim in December is fine.
Summersweet, beautyberry & other summer bloomers: Bloom on new wood.
Coneflower, black-eyed Susan, sedum: Leave seedheads for birds and stems for overwintering insects.