How to Grow and Care for Mountain Mahogany (Cercocarpus)

Cercocarpus spp.

Looking for a hardscrabble shrub for a western native landscape project? Perhaps something with a bit more personality than an imported conifer from the big box store?

Mountain mahogany (Cerocarpus spp.) is a drought-tolerant tree or shrub that requires little care once established, and provides both winter interest and rugged good looks.

A favorite of hikers in the western US, mountain mahoganies grow natively in arid shrubland and semi-desert habitats west of the Mississippi.

These woody shrubs or trees have dense branches and bear small deciduous, semi-evergreen, or evergreen leaves, and in spring or summer, small fragrant flowers.

They present a wind-swept, rugged appearance along the lines of a bristlecone pine and will bring an element of the wild to your cultivated landscape.

In this article you’ll learn all about how to grow mountain mahogany.

Here’s what I’ll cover:

There are nine species in the Cercocarpus genus, which are members of the rose family, Rosaceae.

These nitrogen fixing plants are native to Mexico, as well as the western and central US, and are closely related to cliffroses (Purshia spp.), also from the same regions.

The smallest species reach about three feet tall and wide, while the largest grow to 35 feet tall and wide.

They are called “mahoganies” because their heartwood resembles that of the tropical trees known by the same common name.

The scientific name for the genus, Cercocarpus, means “tailed fruit,” referring to the feathery tail that helps disperse seeds.

Mountain mahoganies thrive in USDA Hardiness Zones 3 to 9, depending on the species.

And, thanks to their extensive root systems, these cold-hardy shrubs or trees can also be employed in erosion control.

How to Grow

In the wild, these trees and shrubs do just fine on their own – but when you grow one in your yard, you’ll need to make sure you have the right conditions and provide the proper care to help them become established in your landscape.

As already mentioned, there are several different species of mountain mahoganies, and they grow in different niches and different types of climates.

Be sure to check growing information for your chosen species as well as using these general guidelines:

Climate and Temperature

These US native plants thrive in dry conditions, where they experience both hot summers and frigid winters.

The temperature adaptation varies depending on the species, with cold tolerance down to -20°F and as high as 100°F.

However, since there are several different species and subspecies, pick one that is native to your region for the best results.

Light

These trees and shrubs require full sun – that’s to say, at least six hours of direct sunlight per day.

In addition to satisfying the light requirement, consider positioning these trees or shrubs in locations where you can view them with backlighting from the sun, which will make their feathery seed tails appear to glow.

Soil

And in general, the soil should have excellent drainage.

Water

Once established, mountain mahoganies are extremely drought tolerant, with mature specimens requiring 15 to 26 inches of rain a year.

In some regions where they grow wild, they only receive 10 inches per year!

You’ll need to provide supplemental water for the two to three years that it takes for the plants to become established before they can survive on such minimal amounts of precipitation.

During hot summer weather and immediately after transplanting, water daily in the first year. In the second year, water weekly during hot weather, and weekly to monthly the third year.

When they are established, plants may need to be irrigated once or twice a month during the summer months, depending on local weather conditions.

Fertilizing

During the establishment period, fertilizer will help, though it isn’t strictly necessary unless you have very depleted soil.

It’s a good idea to conduct a soil test to determine what nutrients are missing from the earth in your garden. Then you can amend accordingly.

If you want to provide some fertilizer but don’t want to test your soil, I suggest a product like Yum Yum Mix which is mild, with an NPK ratio of 2-1-1.

It’s well suited for plants growing in the dry conditions and poor soils of the western US.

Yum Yum Mix Fertilizer

You can pick up a five-pound bag of Yum Yum Mix fertilizer from Soil Mender via Amazon.

For the first few years, you can add a handful of fertilizer to the soil at the base of the plant and water in well.

Species to Select

There are nine or 10 different species of Cercocarpus depending on who you speak to – here’s a selection to get you started:

Alderleaf

Alderleaf mountain mahogany (C. montanus syn. C. betuloides) is also known as true or silverleaf mountain mahogany as well as hardtack.

This species is a deciduous to semi-evergreen shrub with veined leaves that look like those of birches or alders.

It reaches three to 10 feet tall and wide, and can be grown in Zones 3 to 6.

Want to grow your own?

You can purchase packs of 10 alderleaf mountain mahogany seeds from the CZ Grain Store via Amazon.

Curl Leaf

Curl leaf mountain mahogany (C. ledifolius) are upright evergreen trees or shrubs that grow to three to 35 feet tall and wide, though more typically they reach 15 feet tall and wide.

C. ledifolius has leathery, lance shaped leaves, and can be grown in Zones 3 to 8.

Little Leaf

Also known as C. intricatus or C. ledifolius var. intricatus, little leaf mountain mahogany is an evergreen shrub that reaches four to five feet tall and three to four feet wide.

Little leaf mountain mahogany bears small, narrow leaves and is hardy in Zones 3 to 9.

Maintenance

Pruning in early fall or spring can encourage growth – but take care not to cut too much back as these are very slow growing species.

Plan to prune mountain mahogany in late winter or early spring, except for species that bloom in spring – for those it’s best to wait until after blooming.

Learn more about pruning ornamental trees and shrubs here.

Propagation

Cercocarpus species can be propagated from seeds or cuttings, and then transplanted to a permanent location. Let’s look at all three methods.

From Seed

If you can get your hands on seeds, make sure they are less than five years old and be sure to sow in the fall.

Here’s how:

1. Start seeds outdoors to provide temperature variations for better germination rates. Germination can take two months to a year.
2. Alternately, try soaking seeds in a solution containing 30 percent hydrogen peroxide for 30 minutes to break seed dormancy.
3. Sow seeds a quarter of an inch deep, one seed per square foot.
4. Cover with straw mulch and keep the growing medium moist until seeds germinate.

After germination, water frequently during hot weather and protect the young plants from deer.

From Cuttings

Propagation from cuttings in spring or early summer tends to be less dependable than from seed, but if you’d like to give it a try, here are the steps you should follow:

1. Take six- to 12-inch-long cuttings, using sterilized garden pruners. Keep the cuttings in water until they are ready to propagate.
2. Fill four-inch pots nearly full with growing medium, leaving an inch gap between the surface and the rim of the pot.
3. When you are ready to plant, make a perpendicular scrape along the base of the cutting, apply rooting hormone, then insert into the center of the pot.
4. Place the pots in a warm location such as on a heat mat, to keep the temperature around 73°F.
5. Keep the growing medium moist but not soggy, and place in filtered, bright light. Expect rooting to happen within about eight weeks.

When the cuttings are well rooted and there is evidence of new growth, you can transplant into the garden. It’s best to wait until fall to do this.

Transplanting

When you have a specimen to transplant, start by preparing the planting site – preferably in fall.

Clear weeds from the planting location, then dig a hole twice as wide and at least two inches deeper than the nursery pot.

Situate the plant in the center of the hole. If you’re in an arid region, it’s a good idea to plant the specimen an inch or two deeper than the soil level, creating a basin to catch rain water.

Backfill the hole with soil, patting the surface of the ground gently to remove air pockets. Then water in well.

Water daily for the next week or longer, depending on the weather.

Managing Pests and Disease

These native plants are not particularly prone to pest or disease damage, but you’ll want to know what to be on the lookout for, just in case.

Herbivores

The main four-legged nibblers to be concerned about are deer, which love to browse on Cercocarpus plants.

While they generally won’t harm an established specimen, young plants can be damaged by deer browsing, so protect vulnerable plants with fencing.

Insects

These trees and shrubs are known for being quite resistant to insect pests, but weakened specimens may become the targets of flatheaded borers and aphids.

Aphids can usually be removed very simply – with a strong jet of water from a garden hose. Repeat weekly until the pests are gone.

In turn, these caterpillars provide food for the birds and small mammals that make up part of the natural ecosystem.

So keep in mind that when you grow native, the goal is to feed the other members of the ecosystem!

Disease

It’s unlikely you’ll encounter disease problems with your mountain mahogany. Rarely, these plants are affected by anthracnose, canker, and powdery mildew.

Bring Your Hike Home

Beyond the benefits to wildlife and the charms of cultivating a native landscape, growing Cercocarpus in your yard can be a reminder of all those lovely walks in nature you’ve taken – or are dreaming about taking!

Now that you know the essentials, do you have any remaining questions? Are you already growing mountain mahogany in your landscape and looking for an opportunity to show them off? Drop your questions, comments, and photos in the comments section below!

Need more guidance for growing shrubs in the landscape? We have more reading for you right here:

• How to Manage Winter Damage in Evergreen Shrubs
• The 5 Best Shrubs for Hedges High and Low
• How to Grow and Care for New Jersey Tea