Taxonomy of Red Salvia:
Plant taxonomy classifies red salvia plants as Salvia splendens. Despite an official common name of "scarlet sage," many people refer to the plants simply as "red salvia," which is the usage I employ.
Indigenous to Brazil, where it is a perennial, red salvia flowers are known as annual plants in temperate zones: they are damaged by hard frosts and will not survive through cold winters.
Characteristics of Salvia Splendens:
Although the scarlet varieties are the best known, Salvia splendens does come in other colors, including white, salmon, pink, purple, lavender, burgundy and orange. Salvia splendens reaches 18"-30" in height. Its flowers grow on spikes and are quite showy -- thus its popularity.
Sun and Soil Requirements for Red Salvia:
Grow red salvia flowers in a sunny area with a loamy, well-drained soil.
Care for Red Salvia:
To improve their looks and encourage better flowering, deadhead red salvia plants. You can do this by pinching off the flower spikes with spent blooms. Make your pinch fairly far down on their stems. Be on the lookout for snails, slugs and whitefly, all of which may bother red salvia plants.
Uses for Red Salvia in Landscaping:
Red salvia flowers can form a striking accent when massed together as bedding plants or lined up in a row as edging plants. They are also popular in container gardens, where they can serve as a vertical accent. Along with geraniums and impatiens, they are perhaps the first flowers that come to mind for many folks when using annuals to inject a splash of red into the landscape.
Red Salvia Flowers and Salvia Officinalis:
Don't confuse the red salvia flowers we've been discussing with Salvia officinalis. The latter is the culinary herb better known as "sage" and was also used medicinally going back to the Greeks and Romans (hence the genus name, which comes from the Latin for "save").