Xeriscaping is a form of landscaping which requires little to no water. As you might guess, it’s hard to find a ground cover plant that will suit this sort of environment. But I do have one excellent choice to offer: salvia sonomensis, or Sonoma sage.
Indigenous to parts of California, this sage forms a dense mat of grey-green leaves. When it flowers, spikes rise up from within and erupt in lovely blue-violet blossoms. It has a light sage scent, and it can tolerate long periods without moisture.
Ready to learn more about this sage species? Let’s get to it!
Great Products For Growing Sonoma Sage:
|Common Name(s):||Sonoma sage, creeping sage|
|Scientific Name||Salvia sonomensis|
|Zone:||8a-10b, performs best in zones 8-9|
|Height & Spread:||12″-16″ tall, 5 to 15 foot spread|
|Light||Full sun to partial shade|
|Soil||Well draining, with pH between 5.0-7.5|
|Water:||Drought-tolerant when established|
|Pests & Diseases:||Occasional aphids and powdery mildew.|
All About Creeping Sage
As I mentioned above, Sonoma sage is indigenous to California. Also called creeping sage, this perennial is common in foothill and mountain regions. Considered a chapparal plant, it can be grown outside its native environment as well.
Many sages grow throughout California, but this one has a distinct natural range. It can be found in coastal areas from Santa Barbara to San Diego. It’s also found in the Sonoma County region and parts of Napa County. The largest habitat for this plant is along the Sierra Nevada mountain range. There, it grows on southwest-facing slopes below 6000 feet, in foothills and slopes above the central valley region.
All these regions share similar weather conditions. They are arid, but often have nighttime humidity. The summers are hot but not extreme, topping 90-95 degrees but seldom going over 100. Winters rarely drop below 45 degrees for more than a few weeks, and there is almost never snow.
This salvia’s leaves are long spearpoints of silvery-green color. Lightly scented like most sages, its aroma tends to act as a pest repellent. When it flowers, it produces a tall stalk upon which slender, trumpet-like blooms form. These blossoms are often purplish-blue, but some cultivars bloom true purple or white.
Salvia sonomensis does not grow much taller than 8 inches tall. But its flower stalks can hit double that height while in bloom, giving a dual-layered look. What it lacks in height, it makes up for in width. This plant can easily spread in the wild, with some plants reaching nearly 15 feet in width.
Types Of Salvia Sonomensis
There are quite a few cultivars of creeping sage. While its natural form is stunning on its own, these cultivars have varying flower colors. Some are bred for even better drought resistance.
Let’s talk about a few of the most popular cultivars, as well as an extremely popular hybrid!
Salvia sonomensis ‘Serra Peak’
Preferring slightly higher elevations, Serra Peak tends to a blue-purple bloom. It performs best in higher foothill or low mountainous regions, but still remains below 6000′ altitude. Particularly hardy, it can tolerate harsher weather patterns than other creeping sages.
Salvia sonomensis ‘John Farmer Bowers’
This salvia has the same grey-green foliage as its kin, but one dramatic difference. Instead of blue flowers on its stalks, it produces a creamy white colored bloom. A bed made up of this cultivar with other blue or violet-bloomed varieties is lovely.
Salvia sonomensis ‘Fremont’s Carpet’
This fragrant, evergreen perennial is most common in northern California. Its flowers bloom in the spring, and tend towards the purple spectrum. Low in height, it will spread out to cover large swaths of space. Its aroma is quite appealing when sun-warmed.
Salvia sonomensis ‘Hobbit Toes’
Hobbit Toes is a compact growing form. Its leaves are a pale green and are covered in fine white hairs. This gives them a grey-silver appearance. This foliage forms a mat along the ground from which vivid deep violet flowers appear. It likes a little light afternoon shade.
Salvia sonomensis x mellifera, ‘Dara’s Choice’
Dara’s Choice is named after the horticulturist who developed it, Dara Emery. A hybrid of salvia sonomensis with salvia mellifera, it grows to reach heights of 18″ tall. The average spread is 4-6 feet in width. 3-4″ long leaves are a pale green on top with whitish undersides. This hybrid’s flowers are blue-purple and also form on spikes. Developed in Santa Barbara, it thrives in a coastal environment.
Salvia Plant Care
This tough plant handles its own needs more often than not. It’s one of the easiest plants to care for and maintain. But it does have a few preferences to consider. Let’s talk about those.
Light & Temperature
In coastal areas where the temperatures are cooler, this plant should always be in full sun. The same is true in foothill or low mountain areas below 6000 feet. These areas mimic its natural environment.
When the heat index spikes up above 90 degrees on a regular basis, providing afternoon shade is wise. If it’s occasionally too hot, your plants can handle it. Weeks of extreme weather can cause difficulties, though.
It flowers best with at least eight hours of direct sunlight per day.
When established, this plant is extremely drought-resistant. After all, it grows wild in hilly portions of California. These regions seldom receive measurable rain during the summer. At most, they have a little dew that accumulates overnight.
But young plants do need more water. New plants should be watered at least twice a week to develop their deep root systems. Try to avoid wetting down the foliage. Instead, use drip irrigation or water at the plant’s base.
Older plants need at most one light watering session per week, and no watering if it has rained. Mulching around the plant’s base will help prevent moisture evaporation. During excessive heat, an extra light watering in the early morning may be beneficial. This simulates the overnight dew which the plants receive.
Avoid overwatering. Sages are perfect for xeriscaping because of their low water needs. Too much water can cause dieback due to fungal root rots. When in doubt, skip watering.
In the wild, creeping sage often is found in areas with gabbro soil types. These soils are comprised of decomposing igneous rock, and often hold little water.
Outside of their natural environment, gabbro soils are uncommon. We can simulate them to a degree by providing extremely well-draining soils. Sandier soil types are preferred. Avoid hard-packed clay, as the roots cannot easily penetrate it.
If you cannot provide a sandy soil blend, opt for a potting mix which is perlite-heavy to promote as much drainage as possible.
Fertilizer is generally unnecessary for salvia sonomensis. It is tolerant of nutrient-deficient soils, and needs little to sustain itself. This tough little ground cover is determined to live against all odds!
Propagation of Sonoma sage is best via cuttings or seed.
Seeds should be scratched lightly on a sheet of sandpaper to scar their hard surfaces. Once scratched, soak them in water for 24-48 hours. Shallowly plant them within one week of soaking, with just a fine coating of soil over top.
Cuttings should be from young, vigorous stems. Use of a rooting hormone is recommended to encourage fast root development. Place in moist sand or perlite, keeping the potting medium damp until 1-2″ roots form. You can then repot into prepared soil.
Like its relative white sage, this salvia is not tolerant of heavy pruning. Never remove more than a quarter to a third of this plant’s height at any time.
Most pruning will be to remove spent flower stalks. It’s recommended that you allow the flowers to completely dry and to drop their seeds first. They will self-seed and remain perennial in their placement. Once the seeds have dropped, clip the stems at a height to match the rest of the plant.
Sonoma Sage Problems
Tough and resilient, few problems plague this creeping sage. We’ll discuss those rare problems below and how to handle them.
Overwatering can cause dieback of the plant. Most often, this is directly caused by fungi that develop in overly-wet soil. Like many drought-resistant plants, this salvia is at risk of fungal root rots.
It’s best to err on the side of too little water than too much. In fact, if the weather is moderate, you may not need to water at all!
The sage oils which the plant naturally produces in its leaves act as pest-repellent. Very few pests find this or other sages appetizing.
In very rare situations, you may find a few aphids on your plant. This is most true after the plant has recently had a watering. The hollow, woody stems act as moisture storage for the plant’s leaves. After a watering, aphids will pierce the leaf surfaces to drink this sap. A quick spritz of insecticidal soap eliminates these quickly.
What the plant does draw in are beneficial insects. Salvia sonomensis flowers are natural lures for all manner of butterflies, bees, etcetera. Pollinators find this plant to be irresistable. If you’re trying to develop a pollinator garden, this is a perfect choice!
Outside of fungal-origin root rot, the only plant disease that is common is powdery mildew. It can be hard to spot on the grey-green foliage, but at the same time, it rarely causes severe damage. Use a biofungicide to clear up obvious mildews when you spot them.
Frequently Asked Questions
Q: Is salvia sonomensis edible?
A: Technically, most sage species are edible. But this is not a culinary sage, and its flavor does not work well in food uses. If your toddler snacks on a leaf, it won’t cause harm. But I don’t advise tasting it.
Q: Is creeping sage used medicinally?
A: Some tribal groups have used it medicinally, but its relative white sage is far more common for medicinal use. As a general rule, this is only used when something better is not available.
Sonoma sage can be a wonderful addition to your garden. If you’re trying to develop a low-water landscape, it may be just what you’re looking for. The flowers are beautiful, the foliage is distinctive, and its aroma is enticing. Give it a try!