Garden with Betty Cahill: Summer Workhorse Plants 2024

Garden Friend - I thought you might like to read my recent garden article that ran in The Denver Post on summer workhorse plants.

Link to The Denver Post article, click HERE. The full article is below.

Million bells, sapphire sage and other workhorse plants that thrive in Colorado conditions

Calibrachoa (cousin to petunia) is an annual affectionately called "Million Bells." (Betty Cahill, Special to The Denver Post) — Calibrachoa (cousin to petunia) is an annual affectionately called “Million Bells.” (Betty Cahill, Special to The Denver Post)

By Betty Cahill | Special to The Denver Post

PUBLISHED: August 13, 2024

By early August, it’s easy to spot plants that coast through dry and droughty summers like rock stars.

They look good for a reason. They are either happy in their growing conditions (good on ya for choosing the right plant for the right place), or the plant is what I term a workhorse — a garden plant star that thrives in our high altitude, dry, alkaline soil, and low yearly moisture.

Zauschneria, or Orange Carpet hummingbird trumpet, is a Western U.S. native, quick-growing and spreading orange groundcover. (Betty Cahill, Special to The Denver Post) — Zauschneria, or Orange Carpet hummingbird trumpet, is a Western U.S. native, quick-growing and spreading orange groundcover. (Photo from Plant Select)

If you’re new to Colorado, think of Denver metro and the Front Range this way: Boston gets on average of 44 inches of precipitation a year while Denver receives 14 — truly a mere pittance.

Let’s look at six workhorse plants that are well-matched to grow in Colorado.

Annuals

Even though annuals need to be replaced each season and come with a cost, they bring bloom and foliage staying power for season-long interest.

Affectionately called Million Bells, calibrachoa (cousin to petunia) easily meets the high standards of being low maintenance and incredibly showy as long-blooming annuals. The best part is that, except for regular watering and fertilizer (as required with most annual plants), there’s no dead-heading needed for spent flowers. Give them sun to part sun exposure and have fun choosing among the rainbow of colors and energy they bring to your garden all outdoor season long.
Variety is almost a prerequisite in a landscape, and when your eye finds a healthy, plush-looking, silver mound of foliage, then stop the tour bus and grab the camera. Plant Select’s Silver Dollar Plant (Plectranthus argentatus) is one annual worth using every summer because it looks great every summer in containers, beds and borders. Give it room to grow (up to 36 inches tall and 40 inches wide), and once it is established after a few weeks it can handle drier conditions.

Perennials and shrubs

“Fernbush is one of the best shrubs you don’t know you needed or loved until you grow it.” (Photo from Plant Select)

These perennial and shrub assets return and reliably reward us every summer by keeping us in the long-term gardenin

Epilobium canum, also known as Zauschneria, or Orange Carpet hummingbird trumpet, is a Western U.S. native, quick-growing and spreading orange groundcover of light green foliage that radiates with masses of orange-red, trumpet-shaped flowers from mid- to late summer. This long-lived perennial will make your time spent outdoors more pleasurable as you watch the hummingbirds dip and dive for their daily treat. Give it room to spread, water regularly the first year to get it well established, and trim in spring as needed. It tolerates all types of sunlight conditions except dense shade.
Autumn Sapphire Sage (Salvia reptans), is another valued plant in the Plant Select collection. When a plant looks good from the minute it emerges in the spring after its winter haircut and then steadily grows all summer in full sun, with willow-like attractive foliage, and grandly finishes the late summer garden with subtle, sapphire blue pollinator magnet flowers, then plant one or 10, as I did in my garden many seasons ago. There aren’t enough positive adjectives for this plant. Once established, it is drought tolerant, deer resistant and pest free. Seeing this plant in bloom with butterflies and bees galore offsets the eventual sadness of saying goodbye to summer.
There aren’t enough positive adjectives for Sapphire Sage. Once established, it is drought tolerant, deer resistant and pest free. (Photo from Plant Select)

“Fernbush (Chamaebatiaria millefolium) is one of the best shrubs you don’t know you needed or loved until you grow it,” said Plant Select director Ross Shrigley. That got my attention, so it is on my must-have list for fall planting. Fondly referred to by some who grow it as the hydrangea of the West, fernbush is in bloom right now. It is a very drought tolerant, dense shrub growing to 5 to 6 feet tall and wide with ornamental fern-like looking aromatic leaves and abundant long blooming small white flowers. Fernbush retains its leaves late into the fall and later in winter the pretty bronze seed heads are enjoyed by birds. The key to getting the best-rounded shape for fernbush is to prune it each spring which will encourage heavy, tight branching. Expect some internal leaf drop in summer, which is normal for fernbush as it prepares its new growth for next spring.
Gardeners love to grow lavender plants. In two words: They work. As herbs, they provide aromatic fragrance and are used in lotions, sachets and in the kitchen for making lavender shortbread cookies and more. They always look good through the summer in borders, containers and rock gardens. Newer lavender introductions include smaller varieties perfectly suited for the front of the border and smaller gardens. Give Plant Select’s Wee One Dwarf English Lavender a try. Like all lavenders, sharp drainage when planted is a must, along with a mostly sunny location. Wee One grows 8 to 10 inches tall by 12 to 15 inches wide.