Tag Archives: groundcovers

Cultivate Low-Water Lushness with Drought-Tolerant Groundcovers

Soapwort flows past a boulder where Steve, my tabby, acts as overseer. Directly behind Steve, you can see bonfire euphorbia just starting to bloom with bits of yellow bracts showing. To the left of the soapwort sits Pawnee Buttes sand cherry, and in the center of the background is orange carpet hummingbird, which will burst forth with neon orange flowers in the next week or two.

While traveling through Louisiana years ago, I was amazed by the sheer lushness of the trees, grass and flowers.

Here in Colorado, I rarely spot lush residential landscapes.  What can you expect in such an arid climate?  All the same, I love luxuriant gardens in which plants simply flow into each other.

Most trees and shrubs, by their very nature, offer a degree of lushness, which is why homeowners love them.  But groundcovers can add a whole new level of richness.

I’ve been experimenting with various low-water groundcovers to create a sense of lushness in my Fort Collins landscape.  It has taken about four years to get close to achieving the sumptuousness I’m looking for, but I’m making progress.  I’ve propagated new plants from existing ones to keep costs down.

My goal has been to provide successional bloom; in other words, have something new flowering throughout the season for aesthetics and for pollinators.

Here are plants I’ve used successfully.

Spring bloomers

Woolly speedwell (Veronica pectinata).  One of my all-time favorites, woolly speedwell offers an evergreen carpet for flowering bulbs in early spring.  Then around April or May, small blue blossoms emerge on this ground hugger, creating a spectacle of color that lasts for three or four weeks.  Although drought tolerant, woolly speedwell performs best in part shade with regular watering.   To propagate it, dig up a chunk and move it where you need it.

Bloody cranesbill is one of the toughest groundcovers I’ve ever grown. It thrives in both sun and shade, offering a flush of bright fuchsia flowers in the spring.

Soapwort (Saponaria ocymoides).  This sun-loving, evergreen beauty begins blooming in late spring and continues into early summer with a profusion of perky pink flowers.  There’s a white-flowered soapwort, as well.  Soapwort reseeds prolifically, covering a significant amount of real estate in a short time.  Many web sites claim that soapwort spreads 15 to 18 inches.  Don’t believe it.  Some of my pink bloomers routinely grow 40 inches wide and eight inches high.  If you want to discourage soapwort’s spread, simply pull off the seed heads.

Candytuft (Iberis sempervirens).  Candytuft resembles a wedding bouquet with its profusion of white blooms.  The plant’s attractive deep green leaves keep their color year-round.  This underused plant begins flowering in late spring and extends well into June.  Candytuft will grow about two feet wide.  You can divide it for more plants.

Summer bloomers

Bloody cranesbill (Geranium sanguineum).  An early summer bloomer, bloody cranesbill produces bright fuchsia blooms in both sun and shade.  After its initial flush of flowers, this groundcover will continue to produce occasional blooms throughout the growing season.  It grows about 14 inches high and 36 inches wide, and is extremely drought-tolerant.  Propagate it by division.

Rozanne cranesbill (Geranium ‘Gerwat’ Rozanne).  Rozanne is Bloody’s cousin with bigger, longer-lasting blooms.  In my garden, Rozanne grows about 20 inches high and 36 inches wide, and explodes with two-inch-wide purple blossoms from June till September.  Like bloody cranesbill, Rozanne will grow in both sun and shade, and can be propagated by division.  Although drought-tolerant, Rozanne prefers regular watering.

Sumptuous Rozanne cranesbill provides purple blooms from June till September.

Prairie winecups (Callirhoe involucrata).  This hardy groundcover sends out 30-inch runners loaded with rich magenta goblet-shaped blooms.  Winecups begins blossoming in late May and keeps on going till frost.  The easiest way to propagate prairie winecups is by seed.

Bonfire euphorbia (Euphorbia epithymoides ‘Bonfire’).  I’ve loved this mounding plant ever since spotting it at the Colorado State University perennial trial garden years ago.  Its showy red/orange/purple foliage makes this plant a show-stopper throughout the growing season.  But when it blooms, whoa Mama!  Bonfire’s brilliant yellow bracts grab the attention of passers-by, who often pause and ask questions about the plant.  Although often described as a groundcover that grows 18 inches wide, my four-year-old bonfire is 30 inches wide and 14 inches high.

Meidiland groundcover roses perform spectacularly in the garden, especially in hot, dry areas. This fire meidiland, with its double blooms, is a show-stopper.

Groundcover roses.  My favorite groundcover roses are the meidilands, which come in red, pink, yellow and white.  These ground-hugging, weed-squelching stalwarts thrive in the hottest, driest growing conditions and feature stunning, deeply colored blooms.  I favor fire meidiland, in particular, with its lush double blooms, but have also grown red meidiland successfully.  Another delightful groundcover rose is seafoam, a white variety that grows in the White House rose garden.  My only caveat with white roses is that they’ll turn brown if you grow them in sun that’s too intense.  The roses bloom from June till frost.  Groundcover roses are easy to propagate by simple layering.

Hardy plumbago (Ceratostigma plumbaginoides).  This gorgeous plant will grow in sun or shade.  I like growing it under trees.  It’s drought tolerant, but grows best with regular watering.  In July, plumbago delivers striking gentian blue flowers, followed by lovely copper-colored seed heads.  Then in the fall, the foliage turns red.  Plumbago spreads readily by itself, but you can encourage it by digging up a chunk to plant where you need it.

Fall bloomers

Except for bloody cranesbill and bonfire euphorbia, all of the summer bloomers mentioned above continue flowering through the fall.  Another summer/fall bloomer is orange carpet hummingbird (Zauschneria garrettii).

Groundcovers act as organic mulches that save you time and money you might otherwise spend on wood and rock mulches.  If you haven’t used groundcovers on a large scale, I encourage you to try them.



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Ogren’s ‘Allergy-Fighting Garden’ Can Help You Breathe Easier

The reddish-gold leaves of the low-allergen Regent serviceberry brighten a garden in the fall.

The reddish-gold leaves of the low-allergen Regent serviceberry brighten a garden in the fall.

When I consult with my landscape design clients, I typically ask if any family members have allergies. Over the years, I’ve learned that landscaping with low-allergen plants can improve an allergy sufferer’s quality of life considerably.

For a reference guide, I’ve used Thomas Leo Ogren’s Allergy-Free Gardening: The Revolutionary New Guide to Healthy Landscaping. This week, Ten Speed Press released Ogren’s latest book, The Allergy-Fighting Garden, and I like it even better than his earlier book.

In The Allergy-Fighting Garden, Ogren again includes his Ogren Plant Allergy Scale (OPALS) for ranking various plants. He has updated the rankings since publishing Allergy-Free Gardening in 2000. He also devotes a chapter to eliminating mold spores, a major source of allergic reactions. Then there’s his chapter on allergy-blocking hedges.

Ogren rates plants on a scale of 1 to 10, with 1 being lowest in allergens, and 10 being highest. Using Ogren’s rankings, what low-allergen plants might you install in your Colorado garden?

For ground covers, you could use prairie winecups (Callirhoe involucrata), veronica, soapwort (Saponaria), orange carpet hummingbird (Zauschneria garrettii) and cranesbill geraniums, all of which I’ve grown successfully in my Denver garden. They rank from 1 to 3.

Blue iris and pink allium add beauty to your garden without producing masses of allergens.

Blue iris and pink allium add beauty to your garden without producing masses of allergens.

As for taller bulbs and perennials, try iris, allium, tall garden phlox, geum, Jupiter’s beard (Centranthus ruber), hummingbird mint (Agastache), sea lavender (Limonium), wild indigo (Baptisia australis), Butterfly weed (Asclepias tuberosa) and snapdragon (Antirrhinum majus).

Then of course, there are trees and shrubs to consider. They’re particularly important because the males (who are the pollen producers) generate significantly more allergens than smaller plants do. Good choices include hawthorns (Crataegus), barberry (Berberis), butterfly bushes (Buddleia), red chokeberry (Aronia arbutifolia), deciduous viburnums, serviceberries (Amelanchier), and some maples, such as Acer rubrum ‘Autumn Glory’, ‘October Glory’ and ‘Red Sunset.’

Avoid most grasses, especially Kentucky bluegrass, whose male cultivars carry a 9 rating. But be aware that the female cultivars (if you can find one) carry only a 1 rating. A good choice for turf grass is tall fescue, which Ogren ranks at 3.

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Groundcovers Beautify Garden While Preventing Weeds

Plumbago provides a carnival of colors throughout the fall.

Plumbago provides a carnival of colors throughout the fall.

When it comes to weeds, an ounce of prevention is worth a pound of cure.  As you know from experience, it takes a lot of time, money and energy to get rid of weeds once they appear.  What’s worse is when weeds go to seed.  Just one weed can produce hundreds of seeds for current and future germination.

Weeds can pop up anywhere, but their favorite places to show up are bare patches of ground or patches where vegetation is sparse.  That’s why it’s so important to fill spaces between trees, shrubs and other plants in your borders to shade the ground and keep weeds from germinating.  You can fill those spaces with various types of mulch, or you can fill them with groundcovers.

Most groundcovers are one foot tall or less.  But there are taller groundcovers as well.  Ideally, the groundcovers should spread grow densely and spread relatively quickly to keep weeds down.

Attractive spring-blooming groundcovers that meet these criteria include basket of gold (Aurinia saxatilis), prostrate veronica (Veronica prostrata), woolly speedwell (Veronica pectinata), bloody cranesbill (Geranium sanguineum) and June-bearing strawberries (Fragaria). Ever-bearing strawberries send out few or no runners, so if you’re looking for dense coverage, June bearers are a better bet.

Dense summer-blooming groundcovers include prairie winecups (Callirhoe involucrata), Kannah Creek buckwheat (Eriogonum umbellatum var. aureum ‘Psdowns’), orange carpet hummingbird (Zauschneria garrettii), lady’s mantle (Alchemilla mollis) and seafoam artemisia (Artemisia versicolor ‘Seafoam’).  However, seafoam artemisia’s best feature is its curled, silvery-blue foliage rather than its flowers.

A great fall bloomer is plumbago (Ceratostigma plumbaginoides) with its cornflower blue blossoms and copper seed heads.

With its glossy green leaves and double blooms, the sea foam rose enhances the landscape while preventing weeds.

With its glossy green leaves and double blooms, the sea foam rose enhances the landscape while preventing weeds.

For taller groundcovers, try seafoam rose (Rosa ‘Seafoam’), which produces double white blooms from early summer till frost.  This gorgeous, low-maintenance rose is so popular that it grows in the White House rose garden.  The plant grows two to four feet high

Another taller groundcover is Pawnee Buttes sand cherry (Prunus besseyi ‘Pawnee Buttes’).  This hardy, drought-tolerant plant generates showy white blooms in the spring and blazing red foliage in the fall.  It grows 15 to 18 inches tall.

By getting to know groundcovers and their uses, you can enjoy a more beautiful garden with lower maintenance.

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Get a Jump on Gardening with Free Library Programs

Crocodiles enliven this shady "pond" in one whimsical Denver-area garden.

Crocodiles enliven this shady “pond” in one whimsical Denver-area garden.

If you’re eager to get a jump on the gardening season, you’re welcome to attend one of my talks at the Denver Public Library in March and April.  The programs, which are free and open to the public, include:

  • Add Whimsy to Your Garden for Next to NothingTimes and places: Wednesday, March 6, at 6pm at the Smiley branch; Saturday, April 13, at 1pm at the Ross-Cherry Creek branch; and Saturday, April 27, at 2pm at the Bear Valley branch.
  • How to Grow a Low-Sneeze, Breathe-Easy GardenTime and place: Saturday, March 30, at 2pm at the Ross-University Hills branch.
  • 12 Gorgeous Groundcovers for Preventing Weeds. Times and places: Wednesday, April 6, at 6pm at the Ross-Cherry Creek branch; and Sunday, April 14, at 2pm at the Schlessman Family branch.

For details and branch locations, pick up a Fresh City Life brochure at your Denver Public Library branch or visit denverlibrary.org/fresh/mybranch.  The programs run from 45 minutes to an hour.

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