Mexican bush sage (Salvia leucantha) is an evergreen shrubby perennial prized for its dense, arching spikes. It blooms in late summer and early fall with showy cascades of velvety purple flowers good for attracting butterflies, hummingbirds, and other beneficial pollinators. Mexican bush sage makes a great companion plant along with other plants that pollinators favor, such as coneflowers and sedum.
I. Appearance and Characteristics
Salvia leucantha, the Mexican bush sage, is a herbaceous perennial plant that is native to subtropical and tropical conifer forests in central and eastern Mexico. The flowers are usually white, emerging from coloured bracts. It is not frost hardy, but is often grown in warmer latitudes for its prominent arching velvety blue or purple inflorescences.
It grows up to 1.3 m (4.3 ft) high and 2 m (6.6 ft) wide, with numerous erect stems, often arching at their tips, and with long inflorescences. The linear-lanceolate leaves are a soft mid-green, with whitish, hairy undersides.
Although it comes back yearly in the southern states and along the Pacific coast, it is not winter hardy in areas that drop below freezing. It is grown as an annual in most of the United States It is best planted in the spring after the threat of frost passes. It typically grows two to three feet tall within one growing season. It can handle heavy pruning during the growing season but hold off on pruning in late fall or winter. Keeping its dead growth above the surface insulates the plant’s roots.
II. How to Grow and Care
Sunlight
The Mexican bush sage prefers full sun but tolerates partial sun. If located in partial sun, your plant might not be as dense and lush as in full sun.
Temperature and Humidity
The Mexican bush sage is a warm-weather plant that blooms at the end of summer and early fall. It will only survive winters that don’t go below 18 degrees Fahrenheit.
Watering
Water your newly planted Salvia leucantha plants deeply and thoroughly every few days for the first month after planting. Surround the plant with a light layer of organic mulch. After that point, the roots have become more established and can handle an increasingly longer amount of time without water. You only need to make sure it has adequate water until it is established. Reduce watering over time until you are only irrigating during times of drought. Remember, this is a very drought-tolerant plant that thrives in hot conditions so babying it with lots of water isn’t necessary and may prove counterproductive.
Soil
Mexican bush sages require heavier soils than other plants and are not prone to rot in heavy soil. You can work a three- or four-inch layer of organic compost into the soil with a tiller, improving drainage and providing additional nutrients.
Fertilizing
Mexican bush sage is genetically programmed to bloom later in the season, so dousing it with fertilizers will not make it bloom earlier. However, using a liquid organic fertilizer every few weeks throughout the growing season or adding a few tablespoons of a granular organic fertilizer once every 6 weeks from the time of planting will help the plant grow larger and fuller. Since the blooms are produced on the terminal points of all the branches, the more branches the plant has, the more blooms it is likely to produce. That being said, the plant will bloom just fine without a regular fertilization program, but there’s a good chance it will generate more blooms if it’s regularly fed.
Pruning
If you live in a warm climate where winter stays above 18°F and this plant returns year after year, do not prune Mexican bush sage back until the late winter or very early spring. Pruning in the fall could reduce the plant’s ability to survive the winter. Wait until you see new growth emerging and then prune the plant back to a point just above that new growth.
If you live in a cold climate and are growing this plant as an annual, there’s no pruning necessary. In fact, pruning during the growing season could delay the flowering time even further and prevent you from seeing any blooms at all before the arrival of a killing frost in the fall. After the plant has been blackened by frost, you can pull it out and toss it on the compost pile. Alternatively, leave the plant stand through the winter and compost it in the spring..
Propagation
The Mexican bush sage can be propagated with cuttings taken in spring or summer. While you can propagate from seed, propagating via cuttings is a productive use for excess branching. Here’s how to propagate Mexican bush sage with stem cuttings:
- Use clean, sharp pruners to cut a piece of hardwood bearing four to five nodes.
- Strip all but the top set of leaves.
- Dip the end of the cutting into a rooting hormone.
- Plant the cuttings in a pot filled with moist potting mix and place the pot in a warm and sunny location.
- Water well, and after a few weeks, a root system and new foliage should develop.
- When the plant is several inches tall, harden it off before planting it outdoors in the late spring.
Overwintering
If you’d like to overwinter your Mexican bush sage but your climate is too cold for the plant to survive outdoors, you have three options.
- Overwinter the entire plant indoors. To overwinter Mexican bush sage plants and grow them as houseplants, dig them up before the first frost and pot them into large containers with drainage holes. Cut the plant back to a third of its current size. Move the pot into a well-lit room or place it under grow lights. Water it sparingly throughout the winter once every 4 to 6 weeks. Slowly reintroduce it to outdoor conditions in spring, after the danger of frost has passed.
- Overwinter the entire plant in a semi-dormant state. Another option is to pot up your Mexican bush sage and move the pot into a garage or shed that stays just above freezing in the winter. Water it sparingly every 6 weeks. The plant will shift into semi-dormancy so only minimal light is needed. Yes, the plant will likely drop all its leaves and depending on how much light it receives, only the roots may survive. But, come spring, move the plant outdoors slowly (move it back into the garage at night or anytime cold temperatures are expected), and it will sprout new growth from the roots.
- Overwinter cuttings. Another option for those who don’t have the room to overwinter an entire plant is to take a bunch of cuttings using the method described above and grow them on a sunny windowsill or under grow lights until spring arrives. When using this method, you’ll have to pinch the plants back three or four times throughout the winter.
Pests and Diseases
Common Pests & Plant Diseases
Mexican bush sage is susceptible to several pests and diseases. Pest risks include whiteflies, aphids, and spider mites. However, these insects usually attack Mexican bush sages grown in a greenhouse. The plant can also develop diseases such as rust and leaf spot.
Common Problems
The plant is generally low-maintenance and problem-free but is prone to issues common to all woody outdoor plants.
Plant Leaves Falling Off
Leaves infected with rust can cause leaf drop. Rust is a fungal disease that thrives in overly wet soil, so you should adjust your watering practices if you notice leaves falling off your Mexican bush sage.
Yellow Leaves
Like leaf loss, yellow leaves on your Mexican bush sage are often caused by overwatering or an overly nitrogen-rich fertilizer. You can address this issue preemptively by mixing at least 20% sand or grit with compost into your soil. Check the soil to ensure it’s dry enough or well drained if you notice yellow leaves.
III. Varieties of Salvia leucantha
While the straight species has many merits, there are a handful of Mexican bush sage varieties with specific traits that might suit your garden even more. Here are a few of my favorites.
- ‘Santa Barbara’ – A more compact plant than the straight species with a height and width of 3 feet. Looks beautiful in containers or in beds and borders mixed with other late-blooming plants. The flowers are deeper purple than the straight species.
- ‘Midnight’ – This variety has very dark purple flowers and a compact growth habit. It reaches 3 to 4 feet in height with a width of 4 to 6 feet. Sometimes also called ‘Purple Velvet’ or ‘All Purple’, Midnight Mexican bush sage is quick-growing and the foliage is covered with fuzzy hair. In warmer climates, this plant is in bloom from spring through fall. May be slightly less hardy than the straight species.
- ‘Danielle’s Dream’– This is a pink-flowering selection of Mexican bush sage. It’s tough to come by but is worth seeking out. Other names for this plant include ‘FerPink’, ‘Velour Pink’, and ‘Wellington Pink’. It tops out at just 2 to 3 feet in height.
IV. Uses and Benefits
Mexican Bush Sage is a flowering plant that is greatly valued by gardeners for its showy, velvety blossoms. This species is commonly planted in garden beds and garden borders, where its flowers are often cut for bouquets. Mexican Bush Sage attracts bees and butterflies while remaining resistant to deer.
