Are you confused as to when and how to prune your perennials in your garden? Follow these simple instructions and guidelines to make the task easier.
FALL
fall cleanup should include removal of any dead or diseased foliage. Any cleanup you get done in fall makes for less work in the spring and prevents the spread of disease. Water plants well, especially evergreens, before the ground freezes to ensure they are well hydrated over the winter. Fall is a good time to add compost around your plants to improve the quality of your soil, especially clay soil. Mulch can also be added in the fall, preferably after the ground freezes.
anemones: cut back after frost
daisies: cut back to 6 inches in fall.
geraniums (perennial): cut back if frost turns leaves mushy, otherwise leave foliage on over winter.
grasses (ornamental): can be cut back to ground in fall or left intact over winter. If left, cut back first thing in spring, before new growth appears.
hemerocallis/daylilies: remove dead leaves or cut back whole plant to 4 inches. Although these do not have to be cut back in the fall, it will prevent messy/slimy cleanup in spring.
iris (bearded): cut plants back to 6 inches after frost to prevent disease. Overgrown clumps should be separated in late summer or early fall.
ligularia: remove leaves when frost turns them mushy
monarda/beebalm: cut plants back to 6 inches to prevent mildew
peony: cut plants back to 8 inches to prevent mildew
phlox (tall): cut plants back to prevent mildew
poppy: leave foliage over winter for protection. Move or divide in August only
queen of prairie/filipendula: cut back in fall after blooming
salvia: cut back to 8 inches in fall
sunflowers/helianthus: cut back to 8 inches in fall
AFTER BLOOMING
some plants just need deadheading (removing dead flower heads), others need the long flower stalks removed. Others require shearing back the plant by half of its size. Each of these techniques improves the appearance of the plants and sometimes promotes reblooming…
achillea: cut flower stalks back to base after blooming
artemsia: although they do not flower, cut back plant mid May and late July to prevent flopping
asters: cut back to 12 inches after blooming in fall
astrantia major/widows’ tears: shear back after flowering to promote reblooming. Leave foliage on for winter protection
campanula/bellflower: cut flower stalks back to base of plant after blooming
coreopsis/tickseed: shear off flower stems after blooming
daisies: remove dead flower heads after blooming to promote rebloom
delphiniums: cut flower stalks back to base after blooming
dianthus/sweet william: shear plant back after blooming
digitalis/foxglove: cut back flower stalks to base of plant after blooming
euphorbia: cut plant back after blooming to prevent flopping
gaillardia/blanket flower: cut flower stalks back to base of plant after blooming
geraniums (perennial): remove flower stalks after blooming to base of plant to promote rebloom
globe thistle/echinops: cut back late July to promote rebloom
hemerocallis/daylilies: remove flower stalks after blooming
hostas: remove flower stalks after blooming
iris (bearded): cut back flower stalks after blooming
lavender: cut back flower stalks after blooming to promote rebloom
monarda/beebalm: cut flower stalks after blooming to promote rebloom
peony: cut off flower stalks after blooming.
phlox (border): shear back after blooming. Do not cut back in fall.
poppy: plants go dormant after blooming. Leave foliage over winter for protection
rudebekia/black eyed susans: deadhead after blooming if desired, do not cut back
salvia: shear back after blooming to promote rebloom
sedums: cut back both fall blooming and ground cover sedums after flowering. Flower heads can be left on the fall blooming variety if desired for winter interest.
SPRING
wait until soil is no longer soggy to avoid compacting it or damaging bulbs, but don’t wait too long. April is usually best in our zone 4-5 area of Ontario. If plants looks green and healthy, leave them alone. A light cleanup involves removing dead/brown leaves and stems only.
astilbe: foliage protects plant over winter, needs light cleanup in spring only
bergenia: needs light cleanup in spring only
campanula/bellflower: cut plant back in spring. Cut flower stalks after blooming to base of plant
clematis (most): deadhead spent flowers, cut plant back to 6 inches in spring
coreopsis/tickseed: cut plant back to 6 inches in spring. Shear off flower stems after blooming
crysthanthemums/mums: foliage protects plant over winter; cut plant back in spring. Remove faded flower heads after blooming
delphiniums: cut plant back in spring. Cut back flower stalks to base of plant after blooming
diantus/sweet william: foliage protects plant over winter, cut back plant in spring
digitalis/foxglove: requires light cleanup in spring only. Cut flower stalks to base of plant after blooming
echinacea and other coneflowers: deadhead after blooming if desired, only requireslight cleanup in spring
globe thistle/echinops: requires light cleanup in spring only, do not cut back in fall
grasses (ornamental): if not cut back in fall, cut back to ground BEFORE new growth appears in spring
heuchera/coralbells: leave foliage over winter, requires light cleanup only in spring
hosta: leave foliage over winter, cut back flower stalks after blooming
hydrangeas: peegee, annabelle and snowball varieties can be cut back to 12 inches if overgrown
iris (bearded): remove dead leaves to prevent disease. Can be divided in spring if did not bloom previous spring.
iris (siberian): foliage protects plant over winter, cut back in spring to 4 inches
joe pye weed: no maintenance required
lady’s mantle: light cleanup in spring only
lambs ears: light cleanup in spring only
lavender: do not cut back in fall, wait until new growth appears in spring to remove winter kill. Shear flower stalks back after blooming to promote rebloom
liatrus/gayfeather: light cleanup in spring only
lupines: foliage protects plant over winter, light cleanup in spring
red hot poker: foliage protects plant over winter, light cleanup in spring
russian sage: cut back to 6 inches in spring, only after new growth appears
sedum (fall blooming): cut back to 6 inches in early spring if not done so in fall
AFTER BLOOMING
some plants just need deadheading (removing dead flower heads), and some need the entire flower stalks removed. Others require shearing back the plant by half of its size. Each of these techniques improves the appearance of the plants
achillea: cut flower stalks back to base after blooming
artemsia: although they do not flower, cut back plant mid May and late July to prevent flopping
astrantia major/widows’ tears: shear back after flowering to promote reblooming. Leave foliage on for winter protection
campanula/bellflower: cut flower stalks back to base of plant after blooming
coreopsis/tickseed: shear off flower stems after blooming
daisies: remove dead flower heads after blooming to promote rebloom
delphiniums: cut flower stalks back to base after blooming
dianthus/sweet william: shear plant back after blooming
digitalis/foxglove: cut back flower stalks to base of plant after blooming
euphorbia: cut plant back after blooming to prevent flopping
gaillardia/blanket flower: cut flower stalks back to base of plant after blooming
geraniums (perennial): remove flower stalks after blooming to base of plant to promote rebloom
globe thistle/echinops: cut back late July to promote rebloom
hemerocallis/daylilies: remove flower stalks after blooming
hostas: remove flower stalks after blooming
iris (bearded): cut back flower stalks after blooming
lavender: cut back flower stalks after blooming to promote rebloom
monarda/beebalm: cut flower stalks after blooming to promote rebloom
peony: cut off flower stalks after blooming.
phlox (border): shear back after blooming. Do not cut back in fall.
poppy: plants go dormant after blooming. Leave foliage over winter for protection
rudebekia/black eyed susans: deadhead after blooming if desired, do not cut back
salvia: shear back after blooming to promote rebloom
Good luck with your pruning. There are so many varieties of perennials that I have only named the ones popular in my garden zone. Do not hesitate to ask if I have missed something you have in your garden.
I’ll be keeping this for reference!
Hi Lori, I appreciate your gardening tips. I pruned my salvia and peony quickly this morning. I never know when to do these things. I will do the day lilys tomorrow. Happy Thanksgiving
Sylvia
>
Passing this a long as well as a Tree Specialist. Good info!