Rabbitbrush, Ornamental Grasses, and Russian SageRabbitbrush, Ornamental Grasses, and Russian Sage

Fall Garden Cleanup: Don't Prune These

Maintaining Our Gardens To Maximize Their Value As Habitat

by David Salman, Chief Horticulturist & Founder of High Country Gardens

Fall is well underway and many of us are focused on getting our gardens and landscapes ready for their winter rest. With the effects of climate change already impacting our lives, we no longer have the luxury of gardening just for beauty. We must also plant and care for our landscapes to benefit the creatures that share our environment. We can do this by providing habitat, supported by our plant choices and maintenance methods. Here is some guidance as to which plants need to be cut back in fall or winter and which should be left standing until spring to make your garden and landscape more "habitat friendly."

Read on for tips in all areas of your garden:

New Mexico Privet, Russian Sage, and Mountain Pine In OctoberNew Mexico Privet, Russian Sage, and Mountain Pine In October
New Mexico Privet, Russian Sage, and Mountain Pine In October

Deciduous Shrubs & Trees

Winter is an ideal time for pruning deciduous plants (woody plants that lose their leaves), because they are dormant.

  • Most fruit, flowering, and shade trees all benefit from winter pruning. This will help to remove crossed branches, gently shape their branch structure, and, with shade trees, help to maintain strong non-forked leaders.
  • Don't shear the branches of spring flowering shrubs (Forsythia, Lilac, New Mexico Privet, Spirea, Flowering Quince, and others). These shrubs produce flowers on last year's wood, so removing old growth will reduce or prevent flowering. These plants should be pruned immediately after they are done blooming. 
  • Summer blooming shrubs like Russian Sage (Perovskia), Spirea (Caryopteris), and Butterfly Bush (Buddleia davidii and hybrids) should be left untrimmed over the winter months.
    • Russian Sage should be cut back hard in mid-spring, leaving stems 12-15" tall. This should be done every spring to keep them blooming heavily.
    • Blue Mist Spirea and Butterfly Bush should be cut back by 1/3 to 1/2 of their height every third year (NOT annually) to re-invigorate the shrubs and encourage blooming.

Leaves 

Don't kick this valuable resource to the curb! Leaves are a valuable resource for soil building and mulching. They also provide habitat for pollinators, such as bumblebees and beetles, beneficial insects, and wildlife. 

  • Leaves should be raked from lawns but utilized elsewhere in the landscape. Chopping up leaves will help them break down more easily; rake them and put them through a shredder or use a lawnmower to shred them. They can also be added to your compost pile.
  • Use leaves as mulch under trees, shrubs, and evergreens.
  • Use chopped leaves to mulch perennial beds and vegetable gardens.
  • In wetter climates, it's best not to leave layers of fallen leaves on top of your untrimmed perennials and other flower beds, as they will cause problems with fungus and rot. Instead, chop 'em up and use them as mulch to improve your soil.
Fall Garden With Miscanthus Grass and GoldenrodFall Garden With Miscanthus Grass and Goldenrod
Fall Garden with Miscanthus Grass and Goldenrod

Ornamental Grasses

Why leave ornamental grasses standing? There are many reasons to leave these grasses standing over the winter months. Their foliage and seed heads offer texture, movement, and beauty in the winter; they'll be illuminated by the low angled winter sunshine. Plus, many beneficial insects use these grasses to provide protection for overwintering egg masses, larvae, and adult forms. Leaving ornamental grasses standing until late spring gives the insects time for their eggs to hatch and their larvae to change into adults. Birds will also utilize standing grasses as sources for seed and winter shelter. Ground birds, such as quail, will use large ornamental grasses for winter protection.

Switchgrass sways in the autumn breeze. Sedum and Bald Cypress Trees in the background.

Perennial Plants & Flowers 

Why leave perennial plants & flowers standing over winter months? Like ornamental grasses, it's a good idea to leave perennials standing as well. These plants will often provide the same shelter to beneficial insects as the ornamental grasses. 

Seed bearing perennials such as Purple Coneflower (Echinacea), Joe Pye Weed (Eupatorium), Hummingbird Mint (Agastache), Lavender (Lavandula), perennial Sunflower (Helianthus), and others, also provide valuable winter food for songbirds. Additionally, species with stiff stems and ornamental seed heads, such as Yarrow (Achillea), Purple Coneflower (Echinacea), Tall Stonecrop (Sedum), and others with flat or cone-shaped dried flowers, add to the garden's winter beauty.

Plus, perennials are more cold hardy when their stems are left standing over the winter. This is helpful for overwintering perennials that are living at the edge of their cold hardiness zones. For example, when native Sage (Salvia), Hummingbird Mint (Agastache), and Hummingbird Trumpet (Zauschneria) are planted in USDA zones 5 & 6, this will help them survive the winter cold. This is especially true for young plants (in the ground one to two growing seasons).

  • Wait until mid-spring to cut back perennials.
  • If perennial plants are exhibiting some summer/fall disease or are infested with injurious insects, then in these instances, these damaged plants should be cut back, and scraps thrown away in the trash, not the compost, to prevent the disease or pests from spreading.
  • Learn More: Perennial Plant Care In Seasons 1 & 2

 

Gold Yarrow (Achillea) and Mulhy Grass In OctoberGold Yarrow (Achillea) and Mulhy Grass In October
Yarrow (Achillea) and Mulhy Grass add striking textures in this fall garden.

Lawns & Meadows

  • Native Buffalo Grass and Blue Grama Grass, as well as Dog Tuff lawns, should be given the last mowing in late October.
  • Mow the grass high, leaving it at least 4" tall. Never scalp the lawn in the fall, as this weakens it and leaves the stems vulnerable to damage from cold and dry conditions.
  • Grass meadows and wildflower meadows, like ornamental grasses and perennials, should also be left standing over the winter. Mow with the mower deck set high in mid-spring.

Habitat-Friendly Plants From High Country Gardens

  1. Siskiyou Blue Idaho Fescue Grass, Festuca idahoensis Siskiyou Blue

    This is a new selection of the native Idaho Fescue, notable for its enticing spruce-blue foliage. The thin leaves are much longer than the more familiar Festuca glauca, giving 'Siski...

    Learn More
    Siskiyou Blue Fescue Grass Siskiyou Blue Idaho Fescue Grass Festuca idahoensis Siskiyou Blue
    As low as $11.99 Sale $10.79
    Per Plant - 5" Deep Pot
    This is a new selection of the native Idaho Fescue, notable for its enticing spruce-blue foliage. The thin leaves are much longer than the more familiar Festuca glauca, giving 'Siskiyou Blue' a softer, more graceful look.
  2.  Calamagrostis acutiflora Karl Foerster, Calamagrostis acutiflora Karl Foerster, Karl Foerster Feather Reed Grass with Rudbeckia

    The world's most popular ornamental grass, 'Karl Foerster' has a strong upright habit and blooms with showy flowers that ripen to tawny seed heads that decorate the plant through the...

    Learn More
    Karl Foerster Feather Reed Grass Karl Foerster Feather Reed Grass Calamagrostis acutiflora Karl Foerster
    As low as $12.99 Sale $11.04
    Per Plant - 5" Deep Pot
    The world's most popular ornamental grass, 'Karl Foerster' has a strong upright habit and blooms with showy flowers that ripen to tawny seed heads that decorate the plant through the fall and winter months.

Text by Founder and Chief Horticulturist David Salman. 

Banner Image by Saxon Holt, featuring Rabbitbrush (Chrysothamnus), Switchgrass (Panicum virgatum), Silky Thread Grass (Nasella), and Russian Sage (Perovskia)

© All articles are copyrighted by High Country Gardens. Republishing an entire High Country Gardens blog post or article is prohibited without written permission. Please feel free to share a short excerpt with a link back to the article on social media.

by David Salman

Leave Ornamental Grass standing in the fall for winter interest.

Fall is well underway and many of us are focused on getting our gardens and landscapes ready for their winter rest. Here is some guidance as to which plants need to be cut back in fall or winter and which should be left standing until spring.

Maintaining Our Gardens To Maximize Their Value as Habitat

As I have said many times, with the effects of climate change already impacting our lives, we no longer have the luxury of gardening just for beauty. We must also plant and care for our landscapes to benefit the creatures that share our environment by providing habitat with our plant choices and maintenance methods. Here are some tips that will help to make your garden and landscape more "habitat friendly."

Panicum virgatum 'North Wind' in fall.
Gold Plate Yarrow (Achillea) with Muhly Grass (Muhlebergia) in fall.

Deciduous Shrubs and Trees: Winter is an ideal time for pruning woody plants that lose their leaves (deciduous) because they are dormant.

  • Most fruit, flowering and shade trees all benefit from winter pruning to remove crossed branches, gently shape their branch structure and, with shade trees, maintaining strong non-forked leaders.
  • But don't shear the branches of spring flowering shrubs (Forsythia, Lilac, New Mexico Privet, Spirea, Flowering Quince and others), as this will remove the old wood (last year's growth) that produces flowers in the spring.
  • Summer blooming shrubs like Russian Sage (Perovskia), Blue Mist Spirea (Caryopteris) and Butterfly Bush (Buddleia davidii and hybrids) should be left untrimmed over the winter months.
  • Russian Sage should be cut back hard in mid-spring, leaving stems 12-15" tall. This should be done every spring to keep them blooming heavily.
  • Blue Mist Spirea and Buddleia should be cut back by 1/3 to 1/2 of their height every third year (NOT annually) to re-invigorate the shrubs and encourage blooming.
  1. White Chamaebatiaria millefolium, Chamaebatiaria millefolium, Fernbush

    Chamaebatiaria millefolium (also known as Desert Sweet or Fernbush) is a beautiful native shrub that brightens the garden in mid-summer with big clusters of bright white flowers. It ...

    Learn More
    Fernbush (Chamaebatiaria) Fernbush Chamaebatiaria millefolium
    Sale Price I Save 15%
    $12.99 Sale $11.04
    Per Plant - 5" Deep Pot
    Chamaebatiaria millefolium (also known as Desert Sweet or Fernbush) is a beautiful native shrub that brightens the garden in mid-summer with big clusters of bright white flowers. It also has attractive dried seed heads and olive-green foliage. Drought resistant perennial plant (xeric).
  2. Blue Caryopteris clandonensis Dark Knight, Caryopteris clandonensis Dark Knight, Blue Mist Spirea Dark Knight

    Dark Knight Blue Mist spirea (Caryopteris clandonensis) blooms with a profusion of dark blue flowers in late summer when few other shrubs are flowering. Its modest size makes it very...

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    Dark Knight Caryopteris Dark Knight Blue Mist Spirea, Bluebeard Caryopteris clandonensis Dark Knight
    Sale Price I Save 15%
    $11.99 Sale $10.19
    Per Plant - 5" Deep Pot
    Dark Knight Blue Mist spirea (Caryopteris clandonensis) blooms with a profusion of dark blue flowers in late summer when few other shrubs are flowering. Its modest size makes it very useful in smaller yards. A fantastic nectar source for bees and butterflies. Drought resistant/drought tolerant plant (xeric).
  3. White Prunus besseyi ‘PS’ (Pawnee Buttes), Prunus besseyi ‘P0S’, Pawnee Buttesand Sand Cherry

    An outstanding selection of our western native sand cherry, Pawnee Buttes® is a low growing, groundcover shrub with a profusion of fragrant white flowers in early spring and show...

    Learn More
    Pawnee Buttes® Sand Cherry (Prunus) Pawnee Buttes® Sand Cherry Prunus besseyi P011S
    As low as $11.99 Sale $10.19
    Per Plant - 5" Deep Pot
    An outstanding selection of our western native sand cherry, Pawnee Buttes® is a low growing, groundcover shrub with a profusion of fragrant white flowers in early spring and showy mahogany-red foliage in the fall. Drought resistant/drought tolerant plant. Prunus besseyi P011S is a 2000 Plant Select® introduction. 12-18" tall x 4-6' wide.
  4. Blue Caryopteris clandonensis First Choice, Caryopteris clandonensis First Choice, Blue Mist Spirea First Choice

    First Choice is a newer selection with particularly deep blue flowers and a more compact mature size than other Blue Mist spirea. Blooming late summer it is an invaluable nectar sour...

    Learn More
    First Choice Caryopteris First Choice Blue Mist Spirea, Bluebeard Caryopteris clandonensis First Choice
    $12.99
    Per Plant - 5" Deep Pot
    First Choice is a newer selection with particularly deep blue flowers and a more compact mature size than other Blue Mist spirea. Blooming late summer it is an invaluable nectar source for bees and butterflies. Drought resistant/drought tolerant plant (xeric).

    Ornamental Grasses: Leave these grasses standing over the winter months.

  • Their foliage and seed heads offer us winter beauty when the low angled winter sunshine illuminates them.
  • Wait until mid-spring to cut grasses back, as many beneficial insects use these grasses to provide protection for overwintering egg masses, larvae, and adult forms. This gives the insects time for their eggs to hatch and their larvae to change into adults.
  • Birds will also utilize these standing grasses as sources for seed and winter shelter. Ground birds, like quail, will use large ornamental grasses for winter protection.
  • Warm season grasses include Little Bluestem (Schizachyrium), Big Bluestem (Andropogon), 'Blonde Ambition' Blue Grama (Bouteloua), Muhly (Muhlenbergia), Prairie Switchgrass (Panicum), Chinese Maidenhair Grass (Miscanthus), Giant Sacatoon (Sporobolus wrightii) and others. They should be cut back in mid-spring.
  • Cool season grasses, like Blue Avena Grass (Helictotrichon), Fescue grass (Festuca), Silky thread Grass (Nassella) and 'Karl Foerster' Feather Reed grass (Calamagrostis) have evergreen foliage that should not be cut to the ground. Instead vigorously "comb out" dead leaves with gloved hands and clip off the dead leaf tips. In early spring, clip off old seed head stalks as far down into the foliage as possible to leave room for late spring flowers.
  • If the grass plant has a ring of living leaves with a dead center, it's time to divide the grasses to re-invigorate them. (This is necessary once every three to five years depending on the species and growing conditions.)

Perennials: Also leave perennials standing as well.

  • These plants will often provide the same shelter to beneficial insects as the ornamental grasses.
  • Additionally, species with ornamental seed heads such as Yarrow (Achillea), Purple Coneflower (Echinacea), Tall Stonecrop (Sedum) and others with flat or cone-shaped dried flowers, add to the garden's winter beauty.
  • Seed bearing perennials such as Purple Coneflower (Echinacea), Joe Pye Weed (Eupatorium), Hummingbird Mint (Agastache), Lavender (Lavandula), perennial Sunflower (Helianthus) and others provide valuable winter food for songbirds.
  • Perennials that are living at the edge of their cold hardiness are more cold hardy when their stems are left standing over the winter. So when native Sage (Salvia), Hummingbird Mint (Agastache), Hummingbird Trumpet (Zauschneria) are planted in USDA zones 5 & 6, this will help them survive the winter cold. This is especially true for young plants (in the ground one to two growing seasons).
  • Wait until mid-spring to cut back perennials, unless the perennial plants are exhibiting some summer/fall disease or are infested with injurious insects. In these instances, these damaged plants should be cut back.

Leaves: Leaves are a valuable resource for soil building and mulching. Don't just throw them away.

  • They should be raked from lawns, but utilized elsewhere in the landscape where they can be used as mulch under trees, shrubs and evergreens. Or rake them and put them through a shredder, so you can mulch perennial beds and vegetable gardens with the chopped-up foliage.
  • In wetter climates, it's best not to leave them on top of your untrimmed perennials and other flower beds as they will cause problems with fungus and rot. Instead, chop 'em up and use them as mulch to improve your soil.
  • Red Happiness Agastache with Sipa gigantea and Chilopsis in seed.

Grass Meadows and Lawns:

  • Native (Buffalo and Blue Grama Grass) and Dog Tuff lawns should be given a last mowing in late Oct. But mow the grass high, leaving it about 4" tall. Never scalp the lawn in the fall as this weakens it and leaves the stems vulnerable to damage from cold and dry conditions.
  • Meadows, like ornamental grasses and perennials, should also be left standing over the winter. Mow with the mower deck set high in mid-spring.
Gold Plate Yarrow (Achillea) with Muhly Grass (Muhlebergia) in fall.
Gold Plate Yarrow (Achillea) with Muhly Grass (Muhlebergia) in fall.

Text and Photos by Founder and Chief Horticulturist David Salman.

© All articles are copyrighted by High Country Gardens. Republishing an entire High Country Gardens blog post or article is prohibited without written permission. Please feel free to share a short excerpt with a link back to the article on social media websites, such as Facebook and Pinterest.

  1. Pink Agastache Ava

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    As low as $11.99 Sale $10.19
    Per Plant - 5" Deep Pot
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  2. Orange Zauschneria garrettii Orange Carpet, Zauschneria garrettii Orange Carpet, Creeping Hummingbird Trumpet

    2001 Plant Select Winner 4-6" tall x 15-18" wide. Orange Carpet® is a vigorous perennial groundcover that blooms in mid- to late summer with a profusion of bright orange trumpet ...

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    2001 Plant Select Winner 4-6" tall x 15-18" wide. Orange Carpet® is a vigorous perennial groundcover that blooms in mid- to late summer with a profusion of bright orange trumpet shaped flowers. Spreading with underground stems, this beauty is perfect for slopes and cascading over the edges of raised beds.
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    Sale Price I Save 15%
    $11.99 Sale $10.19
    Per Plant - 5" Deep Pot
    Exclusive. Santa Fe is a selected form of Maximilian's Sunflower chosen for its huge, bright yellow daisies that tightly pack the 6 foot tall flowering spike. A tough perennial for difficult growing conditions, it blooms in mid-September. Drought resistant/drought tolerant plant (xeric). A High Country Gardens introduction.
  4. Echinacea purpurea Pow Wow White Photo Courtesy of Walter's Gardens Inc.

    16-20" x 14-16" wide. Pow Wow® White Echinacea is an outstanding, seed grown cultivar that blooms all season with a profusion of white flowers over a compact plant....

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    Sale Price I Save 15%
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    Per Plant - 5" Deep Pot
    16-20" x 14-16" wide. Pow Wow® White Echinacea is an outstanding, seed grown cultivar that blooms all season with a profusion of white flowers over a compact plant.