Because this plant grows so fast, the typical routine is to cut the plant down to just above ground level after blooming is finished in the fall; the new spring growth will be more vigorous with this treatment, and the plant will recover its full size within a matter of a few weeks.
Light
In most regions, this plant will do best in a site with full sun, but in very hot climates it will appreciate some shade during the heat of the day.
Soil
Give the plant moderately fertile, well-drained soil. Autumn sage does well in gravely, rocky soil, but may not tolerate dense clay-based soil.
Water
Water regularly after planting. Once established, plants require only average watering—no more than one inch per week. Do not overwater; in many regions, rainfall is enough. Like most types of salvia, autumn sage does not do well with excess moisture. If your garden soil does not meet this need, consider planting in a container or a xeriscape landscape.
Temperature and Humidity
Native to southern Texas, New Mexico, and Mexico, this type of salvia is tolerant to heat, humidity, and drought. Autumn sage is generally hardy to about 15 degrees Fahrenheit. Lower temperatures can be damaging or deadly to the plants. Autumn sage often remains evergreen through the winter in warmer climates (zones 8 and 9) but is usually deciduous in zones 6 and 7.
Fertilizer
All sage plants are light feeders, and autumn sage is no exception. If your soil is moderately fertile, no additional feeding may be necessary at all. At most, you can apply a handful of balanced slow-release fertilizer around the base of the plant each spring.
Types of Autumn Sage
There are several cultivars of autumn sage, all with similar shapes and growth habits, but with different flower hues:
‘Wild Thing’ is a widely used cold-hardy cultivar with hot pink flowers.‘Radio Red’ is the brightest red of all cultivars.‘Elk Pomegranate’ has raspberry-colored flowers.‘Glimmer Heatwave’ has pure white flowers.‘Ignition Purple’ is a recent introduction with bright purple flowers.‘Furmans Red’ is another bright red cultivar.‘Lowrey’s Peach’ has rosy orange flowers with yellow throats.‘Playa Rosa’ has lovely two-toned pink flowers.
Pruning
An early-season shearing that removes about one-third of the stem length will cause the bush to become very dense and full, though it does slightly delay the first blooms. Flowers can be deadheaded as they fade and wilt; failure to do this may result in many volunteer plants, as this plant will self-seed quite vigorously. During the growing season, individual branches can be trimmed back to the main stems to keep the shrub full and nicely shaped. At the end of the growing season, it’s best to severely prune the shrub back to just above ground level, which encourages quick and robust regrowth the following spring.
Propagating Autumn Sage
Autumn sage is best propagated through softwood cuttings or root divisions. Here’s how to propagate through softwood cuttings: The other common method, root division, is done in early spring as the overwintered stems are just beginning to unfurl their leaves. Dig up the entire root ball with a shovel, and carefully divide it into quarters with a sharp knife or trowel. Immediately replant the divisions into new locations, keeping them well-watered until they are established and actively growing.
How to Grow Autumn Sage From Seed
The seed pods that appear after the flowers have faded can be collected, dried, and split open to collect the seeds inside. The seeds can be started indoors in pots filled with commercial potting mixture blended with sand, or sown directly in the outdoor garden after the last frost of winter. Be aware that seed propagation is a considerably slower process than propagating by cuttings or division. It normally takes about three weeks for the seeds to germinate and sprout, and the seedlings must then be nursed along for many weeks until they are robust enough to transplant into the garden. By contrast, stem cuttings or basal divisions will often produce flowering plants in their first year.
Potting and Repotting
Though it’s not common, growing autumn sage in a container on a patio or deck is perfectly possible. Make sure to use a gritty, well-draining potting mix (potting mix blended with sand is a common formula) and a large pot with good drainage holes. But this is not a successful houseplant that adapts well to moving back and forth between indoor and outdoor locations.
Common Pests and Plant Diseases
Being nearly disease-free and fond of dry conditions, the autumn sage plant is easy to maintain with no serious issues, but there are a handful of pests to watch out for:
Leafhoppers are tiny insects that may create small white or yellow spots on the leaves of autumn sage. The best solution is to use a horticultural soap; chemical pesticides can also control leafhoppers. Slugs and snails will arrive to feed if the ground is covered with too much moist mulch or plant debris. Autumn sage likes relatively dry conditions, which discourages these pests. Rosemary beetles feed on leaves, creating ragged holes. They are best hand-picked off the plants, but if you are squeamish about handling bugs, you can use pesticides to kill them. Remember, though, that chemical pesticides will also kill garden pollinators. Whiteflies and aphids can also be a problem with autumn sage; they are easily controlled with horticultural oils and soaps.
Few plant diseases affect autumn sage, but crown rot can occur if the plant is struggling in poorly draining dense soil. This plant is especially resentful of wet winter conditions.
How to Get Autumn Sage to Bloom
Normally, this plant blooms robustly in spring and early summer, then again in fall, with somewhat more sparse flowering continuing during the heat of summer. A partial shearing after the spring blooms are complete will often stimulate an impressive second flush of flowers. This plant needs lots of sun; shady locations will reduce flowering. And excessive feeding can result in fewer blossoms, as fertilizer tends to promote foliage growth at the expense of flowers. At most, feed once in the spring, using a balanced slow-release fertilizer—most plants bloom fine with no feeding at all.
Common Problems With Autumn Sage
Autumn sage is a largely problem-free plant, but you may notice the following issues:
Leaves Turn Yellow
While there can be a temptation to water frequently during hot spells, these plants don’t tolerate more than about one inch of water per week. If you have regular rainfall, additional irrigation is usually not necessary at all. Too much water often results in yellowing leaves.
Leaves Turn Brown, Fall Off
In very hot climates, autumn sage plants can burn if they receive too much direct sunlight. Prolonged temps above 110 degrees can burn out plants, and in such a climate it is best to grow autumn sage where it gets some shade during the heat of the afternoon.
Wilting Leaves and Stems
Autumn sage may wilt if it is overwatered—or if it is watered heavily at the wrong time of day. It’s best to water in the morning—not in the afternoon, when quick evaporation can raise humidity levels around the plant, causing wilting.
