Mother Nature's Montrose Garden: August 2021

Fourwing Saltbush (Atriplex canescens): Mother Nature's Montrose Garden

As the climate becomes more variable, Western gardeners are switching to plants known for their flexibility and resilience. One such shrub – which also serves as a nice background to flowering plants – is the native Fourwing saltbush, Atriplex canescens. The scientific name is pronounced: AT-try-plex kan-ESS-sens.

The genus Atriplex, the Saltbushes or Oraches, contains over 200 species worldwide and is currently assigned to the subfamily Chenopodioideae of the family Amaranthaceae (note: formerly known as the family Chenopodiaceae). [1] Saltbushes grow in a wide range of habitats, from dry deserts to sea coasts and other moist places. They are known as saltbushes because they can grow in salty soils, often ‘harvesting’ and sequestering salt from the environment. They have also developed several adaptations to dry conditions (more on this below).

Fourwing Saltbush (Atriplex canescens): San Miguel Co, CO.

Fourwing saltbush is a common shrub or sub-shrub (part-woody plant) of western North America. Its range stretches from Western Canada east to North Dakota and south to northern Mexico and Baja California. It is a common sight in many Colorado counties, usually growing on ‘dry slopes and plains, 3800-8800 ft’. [2] It typically – but not always - grows in dry, alkali and often salty soils. In Western Colorado, such soils are often associated with ancient shallow seas.

Fourwing Saltbush (Atriplex canescens): growth habit

Atriplex canescens is a mounded medium to large shrub, typically 3-4 ft tall in sites with little rainfall, but reaching heights of 6-8 ft or more in very favorable sites. The width ranges from two to eight ft. The form is variable across the species’ range; in some places almost tree-like, while in other sites low and compact. Common garden studies (species from different sites raised in the same ‘garden’) suggest that the differences are likely genetic in origin. [3]

Fourwing Saltbush (Atriplex canescens): foliage

Fourwing shrubs are many-branched and evergreen to semi-evergreen, losing at least some leaves to winter cold and/or drought. There is considerable variability in foliage characteristics. But in all sites, plants appear silvery green in contrast to other shrubs. This is due to several factors including: 1) scales that cover young leaves; 2) trichomes (plant hairs) that cover older leaves and small branches; 3) on salty sites, a crust of salt crystals exuded by the trichomes.

The growth rate of Atriplex canescens is at least partly dependent on soil moisture. This plant is an opportunist, growing quickly when resources are abundant and more slowly in times of drought. Its root system makes the most of any soil moisture it receives. Like many of our most drought-tolerant Western shrubs, Fourwing saltbush has both a network of shallow roots and a deep taproot (20 ft. to as much as 40 ft. deep). The roots can utilize both monsoonal moisture and deeper soil water reserves. Not surprisingly, plants in the wild are long-lived, even in harsh climates.

Fourwing Saltbush (Atriplex canescens): in wild

Fourwing saltbush is dioecious; male and female flowers occur on separate plants. But that’s just part of the story. Plants can change sex, usually from female to male, in times of stress (like drought). [4] This is yet another adaptation to harsh and variable conditions.

Fourwing Saltbush (Atriplex canescens): male flowers

Fourwing saltbush isn’t a species to plant for flowers. Both male and female flowers are small and yellow-brown. But the seeds (female plants only) are housed in an interesting dry fruit with four ‘wings’ (bracts) which is unique to the species and attractive in fall and winter (below).

Fourwing Saltbush (Atriplex canescens): green fruits

Fourwing Saltbush (Atriplex canescens): ripe fruits

Atriplex canescens is an important habitat plant in the wild. The fruits and seeds are consumed by birds (including quail, grouse and other birds), rabbits and other small mammals. The fruits and foliage are browsed by Jack rabbits, bighorn sheep, antelope, deer and elk in fall and winter. This browse is high in protein and considered a nutritious food source. Shrubs are often browsed severely by spring (see photo, below). Shrubs also provide cover for small and medium-sized animals and birds. And insects, including lacewings, ladybugs, hoverflies and the larvae of Mojave & Saltbush Sootywing Skippers, eat either the foliage or insects on it. [4,5]

Fourwing Saltbush (Atriplex canescens): browsing elk

Fourwind saltbush is easy to grow in USDA Zones 6-10. It tolerates a wide range of soil textures, from sandy or gravelly to loams, with pH from 6.5 to 9.0 (alkali). It can be grown in full sun, even in hot gardens, but also tolerates some shade. It does need good soil drainage, particularly in areas with abundant rain, and is very drought tolerant once established.

Give it weekly water for the first summer or two, then once a month or less thereafter. In fact, there’s a greater danger over over- than under-watering established plants. Plants may be susceptible to root fungi, so plant them in a drier part of the garden, if necessary.

Fourwing Saltbush (Atriplex canescens): tolerates
drought and salty soils

As mentioned above, wild Fourwing shrubs are often well-browsed during fall and winter. They are designed to take a yearly shearing, so don’t hesitate to cut branches back by 1/3 in late winter or early spring. Pruned plants will be heathier, bushier and better looking than those left unpruned. And that’s about it for this hardy, disease-free shrub.

Fourwing Saltbush (Atriplex canescens): fruits are showy

So how can Atriplex canescens be used in the garden? If you have a hot, dry area where little else grows, you might want to consider it. It’s a good alternative to the cacti (or non-living ground covers) often used in such situations. If given a yearly pruning it’s tidy enough for the front yard; no one will even suspect it’s a native! It is also a good choice for a sheared hedge, due to its dense foliage; or can be included in a mixed hedgerow.

Fourwing Saltbush (Atriplex canescens): good choice
for dry conditions

In areas where Fourwing saltbush is native, it can provide an effective transition to wildland areas or a backbone shrub for local native plantings. We like it mixed with other native shrubs and flowering perennials (below). The silvery-green color of Atriplex canescens contrasts beautifully with the silvers and deep greens of other plants. It is relatively fire-resistant compared to other Western native shrubs, which is another plus. And, of course, its habitat value makes it a good choice for attracting wildlife.

Fourwing Saltbush (Atriplex canescens): foliage provides
nice contrast year-round

Atriplex canescens has been put to good use by humans as well. The leaves can be harvested and eaten, raw or cooked, most times of the year. The one exception is if your soil is high in selenium; this plant is a selenium-accumulator, so leaves should not be eaten from selenium-rich soils. The seeds are tiny, but can be ground for flour or pinole. [4]

The leaves produce a soapy lather for hair washing or to relieve itchy skin, rashes and insect bites. Leaves and roots can be used to make a soothing poultice for insect bites and stings. [6] The Hopi burn green foliage for an ash that enhances the color of blue corn products. This ash can also be used as a baking powder substitute. [3] And the foliage yields a yellow dye.

We are big fans of Fourwing saltbush. It’s a tough-as-nails, drought tolerant shrub that adds beauty and usefulness to the garden. It isn’t showy, but it fills a niche that few other native shrubs do so well. It is most often available from local native plant nurseries, though we suspect it may become more common in the future. We suggest you seriously consider it for your future-resilient garden!