The genus Salvia, commonly known as sage, is a diverse group of plants used widely in ornamental gardening for their vibrant flowers and aromatic foliage. The question of whether a salvia plant returns each year does not have a simple answer. This is because the genus includes plants with fundamentally different life cycles. Whether a specific salvia variety “comes back” depends entirely on its botanical classification and the climate in which it is grown.
The Salvia Spectrum: Annuals, Perennials, and Biennials
The determination of whether a salvia will return begins with its natural life cycle, which falls primarily into two categories. An annual salvia completes its entire life cycle—from germination to seed production—within a single growing season before dying completely. This requires replanting every spring. A common example is Salvia splendens, or scarlet sage, a popular bedding plant in cooler climates.
A perennial salvia possesses a root system that lives for three or more years, allowing the plant to re-sprout new growth each spring. These plants may die back to the ground in winter, but their root crowns survive beneath the soil surface. Many salvias treated as annuals in colder regions are actually tender perennials native to warmer tropical or subtropical zones.
Hardiness: The Role of Climate and Zone
A plant’s life cycle is only half the equation, as its ability to survive is tied directly to the local climate. Gardeners rely on the USDA Plant Hardiness Zone Map, which categorizes regions based on their average annual minimum winter temperature. A perennial must be rated to survive the lowest temperatures in its specific zone to reliably return.
For instance, hardy Salvia nemorosa (Woodland Sage) survives in zones as cold as 4. If a gardener in Zone 5 plants a tender perennial like Mexican Bush Sage (Salvia leucantha), hardy only to Zone 8, the plant’s root system will likely be killed by the first hard frost. In this situation, the tender perennial is functionally treated as an annual. The difference between a salvia that returns and one that does not comes down to matching the plant’s cold tolerance to the local minimum temperature.
Overwintering Care for Perennial Salvias
For salvias rated to survive the local climate, strategic care in late fall and winter increases their chances of a strong return. While some gardeners cut back dead stems in the fall, leaving the stalks standing provides insulation and protects the crown from harsh winter weather. It is preferable to wait until early spring to cut back the old stems, specifically when new green shoots begin to emerge from the plant’s base.
Proper mulching insulates the root crown and prevents frost heave, where freezing and thawing cycles push shallow-rooted plants out of the ground. Apply a loose, organic mulch, such as straw or shredded leaves, in a layer about 2 to 3 inches thick. Ensure the mulch does not directly touch the plant’s crown. This gap prevents moisture accumulation around the central growth point, which can cause rot. Dormant salvias require minimal supplemental watering during the winter, as cold, saturated soil is more damaging than dry soil.
Strategies for Protecting Tender Varieties
Gardeners who wish to save tender perennial salvias that cannot survive the local ground freeze must intervene before the first hard frost.
Overwintering Potted Plants
One strategy is to treat the plant as a temporary container plant by carefully digging it up and potting it in the fall. The plant should be trimmed back to 4 to 8 inches to reduce foliage. Move it to a cool, dark, and frost-free location, such as an unheated garage or cellar, where the temperature stays between 40°F and 50°F.
Taking Cuttings
Alternatively, gardeners can take cuttings from the plant in late summer or early fall as an insurance policy against winter loss. These small stem sections can be rooted indoors under bright light, growing into small, new plants over the winter. This method requires less space than overwintering a full-sized plant and ensures a supply of young salvias ready for spring planting.