How to Grow Scarlet Sage Flowers in Your Garden

Scarlet sage (Salvia splendens) lights up the garden with tall spikes of tubular flowers. While red flowers are the most popular color, new cultivars boast white, purple, and pink flowers. All of these flowers attract dazzling displays of hummingbirds and butterflies. Plus, no matter what color flowers you choose, you’ll end up with a low-maintenance plant, in my experience. Here, I’ll take you through everything you need to know about growing and caring for Scarlet Sage at home, including planting, soil considerations, light preferences, feeding, pruning, and over-winter care. 

How to Grow Scarlet Sage (Salvia splendens)

Scarlet Sage Cares Basics:

Botanical Name:Salvia splendens
Also Known As:Scarlet sage, red salvia
Hardiness Zones:Can survive winter in zones 9-11, can be grown as an annual in zones 4-8
Flowering Months: May through November
Growing Difficulty:Easy
Type of Plant: Perennial, treated as an annual in cold areas
Light Requirements:Sun to part shade, prefers at least six hours of sun
Temp & Humidity:Thrives in temperatures between 60-90ºF, cannot survive temperatures below 32ºF
Watering Needs:Water about once a week in the summer and once every two weeks in spring and fall
Soil Preferences:Well-drained; prefers sand or loam
Feeding:Fertilize in the late spring and summer with a fertilizer designed for flowering plants
Growth Expectations:Up to two feet tall and two feet wide

How to Grow Scarlet Sage

Bright red Scarlet Sage flowers growing in a garden

Choosing a Location

Fortunately, scarlet sage plants aren’t too particular about their location. While they prefer full sun, they can survive in part shade and full shade.

Due to their tall form and dramatic flowers, these salvias make great additions to mixed flower beds as well as borders. Plant a line of these plants, and you’ll end up with a brilliant edge along a path or fence.

They also work well as container plants and add dramatic height to mixed planters.

No matter where you plant scarlet sage, you’ll want to check the drainage. If an area appears continually moist, it’s best to choose another location.

Best Times of Year to Plant

The best time to plant scarlet sage is in the spring after the danger of frost has passed. This will allow the plant to become established before the summer heat arrives.

If you live in an area without frost, you can also plant scarlet sage in mid-fall. The cool temperatures will allow plants to establish a strong root system so they can take off the following spring.

Growing From Seed vs. Transplanting

A cluster of Scarlet Sage grown from seed in a well manicured ornamental garden surrounded by groomed hedges

It is possible to grow scarlet sage from seed or transplants.

If you’d like to grow these plants from seed, you must plan ahead. Start seeds indoors about 6-8 weeks before the predicted last frost date. To provide the seedlings with enough light, place them near a sunny window or use a grow light.

Before you plant the seedlings outdoors, make sure to harden them off. This involves placing them outside for a few hours and then a few more hours the next day. Plants will be acclimated to the cold by the time you are ready to plant.

If you purchase transplants, wait until the danger of frost has passed. Then, you should harden them off before planting them in the ground.

What to Do Before Planting

Before you plant scarlet sage, you should inspect the area. Ensure the soil is well-draining and there are no signs of puddling.

If you are planting a mixed flower bed, lay out your plants before you plant them. Ensure each plant has enough room to grow without becoming crowded.

If you’re incorporating scarlet sage as part of a container planting, ensure the pot has drainage holes.

Best Soil Types

Scarlet sage isn’t too particular about soil.

The ideal soil for it is sandy loam, but it can thrive in any well-drained soil. It prefers a soil pH of neutral to slightly acidic.

How to Plant

If you are planting in the spring, it is essential to allow transplants to acclimate to outdoor conditions. Allow potted plants to sit outdoors for a few days before you plant them.

Once ready to plant, dig a hole a few inches larger than the plant’s root ball. Place the plant in the hole, cover it with soil, and water well.

Light Preferences

Scarlet sage blooming in a partially shaded location in a garden

Scarlet sage thrives when it receives at least six hours of bright light each day. However, it can also grow well in part-shade or dappled light.

While plants won’t die in full shade, they won’t thrive. Expect stunted plants and a lackluster flower display.

Temperature & Humidity Preferences

Salvia splendens prefers summer temperatures between 65-90ºF. Lower temperatures will slow plant growth.

Unfortunately, this plant is not frost tolerant. It will die if temperatures fall below 32ºF.


How to Care for Scarlet Sage

A collection of well cared for Salvia splendens flowers in bloom

Watering 

Scarlet salvia plants like soil that is moist but not wet.

During the summer, expect to water plants once a week during drought. If you receive substantial rain, you can skip watering.

Be aware that scarlet salvia plants are prone to root rot. If the top few inches of soil is wet, there is no need to water.

Fertilizing

Salvia splendens will benefit from regular fertilization.

To encourage a lot of flowers, fertilize once in the late spring with a fertilizer designed for flowering plants. For continuous blooms, fertilize once a month in the summer.

Pruning

A collection of potted Scarlet Sage flowers in bloom showcasing tall plumes of red flowers

Scarlet sage doesn’t require regular pruning, but removing dead flowers and stems will keep it tidy.

If you are growing scarlet sage as a perennial, you can prune the plant in late winter. Use a sharp pair of pruning shears to cut the plant back to four to six inches tall. This will encourage new growth and flowers.

Propagation

Scarlet sage is easy to propagate via seed and stem cuttings.

Seed

If you’d like to grow new plants from seed, start seeds 6-8 weeks before you want to plant them outside. Keep seeds warm and moist until they germinate. Once seedlings have emerged, provide bright light so the plants can grow.

Stem Cuttings

Since many scarlet sage cultivars are hybrids, seeds won’t produce plants that resemble the parents. You can use stem cuttings to produce plant clones of the parent.

To propagate scarlet sage via stem cutting, follow these steps.

  1. Cut a piece of stem that is 4-8 inches long.
  2. Remove any leaves from the bottom two inches of the stem.
  3. Place the cutting in a glass of water so the cut end is submerged. Ensure that no leaves are in the water.
  4. Place the glass and cutting in an area with indirect light.
  5. Change the water every few days.
  6. After a few weeks, you should see roots form. Allow these roots to grow until they are at least half an inch long.
  7. Pot up the cuttings in a container filled with potting mix.

Overwintering

A close shot of deep red scarlet sage flower against green leaves and foliage

Scarlet sage can survive the winter in areas that do not receive frost.

If you live in an area that receives only one or two light frosts per year, plants may survive with some help. If frost is forecasted, cover your plant with a piece of frost cloth or bedsheet. Remove the covering the next day.

If you live in an area with cold winters, it’s best to grow scarlet sage as an annual. 

However, you can overwinter it indoors. To do so, dig up the plant and place the root ball in a container. Store the plant in a cool, dark area until spring arrives.

Repotting

If you’re growing scarlet sage as an annual container plant, you won’t need to repot it. Just make sure you give it enough space to start.

If you’re growing a perennial container plant, you should repot every two or three years. Repot in the late winter or early spring.

When it comes time to repot, remove the root ball from the container and brush off excess soil. Add a few inches of new potting soil, add the plant, and fill with more potting soil.

Deadheading

Deadheading will encourage scarlet salvia plants to produce new blooms. You should begin deadheading in early to mid-summer and continue through the fall.

Deadheading involves removing all dead flowers. Since scarlet sage flowers grow on a stalk, you’ll want to remove the whole stalk. Use a pair of sharp shears to cut the flower stalk a few inches from the ground.


Common Problems and How to Treat Them

Scarlet sage flowers growing in a garden patch

Fortunately, scarlet sage plants don’t deal with many diseases or pests. Due to a strong odor, they are resistant to rabbits and deer.

The most common problems are powdery mildew and root rot. While these diseases can occur naturally, they are often caused by an improper environment.

Proper plant spacing and at least six hours of sun will help prevent powdery mildew and other foliage fungi. 

Root rot, a fungus that affects roots, is often caused by overwatering or poorly drained soils. Ensure to only water when the top few inches of soil is dry, and use containers with drainage holes.

Essential Tools

A selection of garden tools and accessories

Scarlet sage doesn’t require too many specialized tools, but the following items will be useful:

  • Soaker hose or watering can
  • Pruning shears
  • Perlite or sand
  • Soil probe or moisture meter
  • Mulch, compost, or slow-release fertilizer pellets

Growing Scarlet Sage FAQs:

How Big Does Salvia splendens Get?

Salvia splendens can grow up to two feet tall and two feet wide.

What Do You Do With Scarlet SageOver Winter?

If you live in zones 9-11, scarlet sage will survive the winter without any additional care. If frost is expected, cover your plant with a piece of frost cloth or bedsheet. Remove the covering once temperatures rise above freezing.

Scarlet sage plants will not survive heavy frosts. If you’d like to save your plants, you can dig them up and bring them inside over the winter.

Is Scarlet Sage Invasive?

No, scarlet sage is not invasive.

Is Scarlet Sage a Perennial?

Yes, scarlet sage is a perennial. However, it is often treated as an annual in cold climates.

How Do You Deadhead Scarlet Sage?

Once flowers have died, you should remove entire flower stalks. Use a pair of pruning shears to cut the flower stalk a few inches above the ground.

Will Scarlet Sage Grow in Shade?

Scarlet sage will grow in shade, but it prefers part-shade or full sun. If grown in full shade, it will appear stunted.

Wrapping Up

If you want a low-maintenance yet show-stopping flower, scarlet sage is a great choice.

Contributing Editor | briana@petalrepublic.com | Full Bio

Briana holds a B.S. in Plant Sciences from Penn State University. She manages a small market garden where she grows vegetables and herbs. She also enjoys growing flowers and houseplants at home.

Spread the love

Leave a Reply

Your email address will not be published. Required fields are marked *