Black dalea is an airy, delicate-looking shrub that is much tougher than it looks. It’s actually a resilient landscape plant that thrives on neglect. Here’s everything you need to know about growing this Chihuahuan Desert native.
Black dalea (Dalea frutescens) is a medium size shrub with small, dainty leaves and flowers that belie how tough it is. It has fine, fern-like, gray-green leaves composed of tiny leaflets. Clusters of small purple flowers dot branch tips. Its seed pods are inconspicuous.
So it can come as a surprise to learn that this delicate-looking shrub is a Chihuahuan Desert native that thrives in full sun, drought, and temperature extremes. When grown as a landscape plant, it suffers more from too much attention (watering, pruning, fertilizing) than from neglect.
It blooms in the fall and is at its best when many shrubs are looking tired after a long, hot summer.
Black dalea is a source of nectar for bees, butterflies, and hummingbirds. It’s also a larval host for several species of butterflies.
Why I Like This Plant
- Lacy, fern-like foliage
- Purple flowers in the fall
- Thrives on neglect
- No thorns, non-toxic, low litter
- Supports bees, butterflies, hummingbirds
Things to Watch Out For
Black dalea is semi-deciduous and occasionally goes bare. It may lose its leaves in the winter, depending on how cold it gets. It can also lose its leaves during summer drought.
Both deer and rabbits like to nibble on this plant, especially when it’s young, so keep that in mind if these hungry critters frequent your yard.
Optimal Growing Conditions
If you’re thinking of adding a black dalea to your garden, you need to find a suitable place that will keep your plant healthy and looking good… while minimizing maintenance for you.
Here are the key factors to keep in mind.
Temperature
Black dalea should be grown in USDA Hardiness Zones 6 – 11. It’s a heat lover that thrives in the hottest spot in your yard and tolerates cold down to 0℉.
Sun Exposure
As a Chihuahuan Desert native, black dalea likes full sun and doesn’t mind reflected heat. Plants tolerate some part shade, but need at least 6 hours of full sun to look their best. They get leggy with too much shade.
Size and Growth Rate
Black dalea grows moderately fast. Plants typically reach a size of 5 feet tall by 4 feet wide.
Soil
In its natural habitat, black dalea grows on dry, limestone hills. It grows well in most native soil — rocky, sandy, limestone, or gravelly — provided it’s well-draining. It does not do well in heavy clay.
Other Location Considerations
Since it is non-toxic, has no thorns, and is low-litter, it’s a plant you can place near a sidewalk, driveway, pool, or patio, or anywhere else it might come in contact with people or pets. But, of course, be mindful that it can attract bee activity.
Black Dalea:
The Essentials
| Common Name | Black dalea |
| Scientific Name | Dalea frutescens |
| Origin | Chihuahuan Desert |
| Plant Type | Semi-deciduous shrub |
| USDA Zones | Zones 6 – 11 |
| Cold Hardiness | To 0℉ |
| Flower Color | Purple |
| Flower Season | Fall |
| Mature Size | 5’ high x 4’ wide |
| Growth Rate | Moderate to fast |
| Sun Tolerance | Full, reflected sun |
| Water Needs | Low |
| Pests & Diseases | Root rot |
| Garden Friendly | No thorns, non-toxic, low litter |
| Wildlife | Attracts butterflies, bees, hummingbirds |
How to Plant
The rule of thumb when planting any shrub in the desert is to dig a hole three times as wide as the root ball but no deeper.
Amending the soil is not recommended. Counterintuitively, backfilling with the same native soil you just dug up helps your black dalea develop a stronger root system.
When to Plant
The best time to plant black dalea is in the fall. This gives it three seasons to grow roots and get established before the following summer.
The second best time is in spring, the earlier the better. This still gives your shrub time to get established before the intense heat of June arrives.
How to Care for Black Dalea
Whether you’ve recently planted a black dalea or have an existing plant in your yard, here’s how to take care of it to keep it healthy and looking its best.
How to Water New Plants
Once you’ve got your shrub in the ground, watering is your most immediate concern. Here is the recommended watering schedule for new shrubs planted in the spring or fall.
| Weeks 1 & 2 | Every 3 – 4 days |
| Weeks 3 & 4 | Every 5 – 7 days |
| Weeks 5 & 6 | Every 7 – 10 days |
| Weeks 7 & 8 | Every 10 – 14 days |
After week 8, gradually extend the time between waterings.
How to Water Established Plants
Once your shrub is established, water it twice per month during the summer and once per month in spring and fall. There’s no need to water during the winter, unless you’ve experienced extreme drought.
Take care not to overwater this plant. Too much water can cause root rot, leggy growth, and fewer flowers.
Too little water in the summer can result in leaf drop.
Should You Fertilize?
Black dalea doesn’t need fertilizer. This plant has evolved to get all the nutrients it needs from poor, desert soil. And like all members of the legume family (Fabaceae), it fixes nitrogen, which naturally improves its surrounding soil.
Fertilizer can actually reduce the number of flowers.
How to Prune
Black dalea should be pruned back by one-half to one-third every 2 years in late winter to early spring. This keeps plants compact, dense, and bushy, and encourages more flowers.
Plant Lover Facts
Black dalea (Dalea frutescens) is also called black indigo bush and black prairie clover. The only explanation I’ve heard for the descriptor “black” is that it’s named for its black seed pods.
It’s native to New Mexico, Oklahoma, Texas, and northeastern Mexico.
The genus Dalea, not to be confused with the genus Dahlia, is named in honor of the English naturalist Samuel Dale.
There are several species of Dalea grown as desert landscape plants, but black dalea produces the most flowers.
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Author Bio
Deane Alban is the creator of Southwest Gardener. She is a science writer with a bachelor’s degree in botany from the University of South Florida. Gardening is her lifelong passion. She’s been gardening in Tucson for over 15 years.
