Ornamental · Lamiaceae
Salvia (Annual)
Salvia splendens
Pop scarlet sage in full sun and keep it watered, and you'll get flower spikes right through to frost.
Full sun
Every 3–7 days
50–90°F · 10–32°C
USDA 10–11
Overview
So what's annual salvia? It's scarlet sage, the bedding plant with those tall, fire-red spikes you spot along summer beds. It's part of the mint family, and here's the catch: it's really a tender perennial that only makes it through winter in zones 10 and 11. Everywhere else, folks just grow it as a warm-season annual and pop in new plants come spring.
The payoff? Color that hangs around. Those spikes start opening in early summer and don't quit until the first frost, and the bright tubular flowers are a magnet for hummingbirds and bees. Plants stay tidy at somewhere around 8 to 36 inches (20 to 91 cm) depending on the variety, so they'll fit a bed, an edge, or a pot on the porch.
Worried it'll be fussy? It won't. All it really wants is sun, warmth, and soil that doesn't dry out hard, and it'll flower without much help. Just snip off the spent spikes now and then, and the color keeps rolling all season long.
Care
The short version: full sun with maybe a bit of afternoon shade, soil that stays evenly moist instead of bone dry, a slow-release feed when you plant, and a quick deadhead now and then to keep those spikes coming.
Light
Salvia flowers best in full sun, though it won't mind a little afternoon shade if your summers get brutal. Give it too much shade, though, and it'll stretch out tall and floppy with way fewer spikes to show off.
Water
Keep the soil evenly moist, because this one's no fan of drought. Check the top inch, and once it starts drying out, give it a drink, more often if it's in a pot or the weather's hot. Let it get too dry and the flowers are the first to sulk.
Soil
It's happiest in well-drained loam with some organic matter mixed in, but honestly it'll get by in average soil too. And pH? It's not picky, anywhere from 6.0 to 8.0 suits it fine.
Temperature
Salvia likes it warm, roughly 50°F to 90°F (10°C to 32°C), and frost will finish it off fast. So hold off until both the soil and the air have warmed up before you plant it out.
Humidity
Regular outdoor humidity is plenty, so there's no number to chase here. What really counts is airflow, since plants packed together in stuffy air are the ones that end up with powdery mildew.
Feeding
Mix a slow-release fertilizer for annuals into the soil when you plant, then just top it up with a light feed as the season rolls on. That easy, steady feeding keeps the spikes coming without pushing out soft, floppy growth.
Pruning
Keep deadheading the faded spikes through summer and the plant will just keep flowering. If it gets leggy after a big flush, don't worry, shear it back and it'll bush right out again.
Size & spacing
Depending on the variety, you're looking at 8 to 36 inches (20 to 91 cm) tall and an 8 to 18 inch (20 to 46 cm) spread. Give each plant a little room so the air can move through, and you'll keep mildew from moving in.
When to plant
Here's the thing about salvia: it can't stand frost, so it's all about warmth. Start the seeds indoors in late winter or early spring, and don't rush the young plants outside until the last frost's behind you and the soil's warmed up. After that? The spikes just keep going from early summer until the cold finally calls it a season.
Northern hemisphere
Southern hemisphere
Typical months for a temperate climate: start earlier in warm zones, later where spring frosts linger.
- Sow: 6 to 8 weeks before the last spring frost; do not cover seed as light aids germination
- Plant: After the last frost when soil and air have warmed
- Harvest: Summer to frost (roughly June until first fall frost)
Hardiness
USDA hardiness zones: 10–11
Temperature: down to -1°C
Troubleshooting
Most of salvia's little troubles turn up early, either while the seedlings are tiny or when plants get crammed together in still air. Catch them soon and they're usually quick to sort out. Just find the symptom below that matches what you're seeing and step in before it spreads.
Seedlings keel over and rot right at the soil
If your seedlings suddenly flop and rot, that's damping-off, a soilborne fungus that loves cold, soggy seed-starting mix and pinches the little stems off at the surface. Toss the ones that went down, let the mix dry out a bit between waterings, and get more air moving over the tray. Then just resow in fresh sterile mix and clean pots, keep it warm, and you should be fine.
Fix:
- Discard affected seedlings
- Improve air circulation and let the surface dry between waterings
- Use sterile mix and clean containers for resowing
Plants wilt fast and rot at the base in hot, wet soil
If a plant wilts even though the soil's still damp and the base is going rotten, you're probably looking at southern blight or southern bacterial wilt, which love hot, waterlogged ground. There's no saving it, so pull the plant and toss it before it spreads. Then fix the drainage and give a different annual that spot next year.
Fix:
- Remove and destroy affected plants
- Improve drainage
- Avoid replanting susceptible annuals in the same spot
That white powdery stuff creeping over the leaves
See a chalky white film on the leaves? That's powdery mildew, and it shows up when plants are crowded and the air just sits there. Give them more space, pull off the worst leaves, and stop splashing the foliage late in the afternoon. Pop them in full sun with room to breathe and it won't come back.
Fix:
- Increase spacing and airflow
- Remove badly affected foliage
- Avoid overhead watering late in the day
Twisted shoots, sticky leaves, and teeny bugs
Warped new growth with a sticky feel usually means aphids, whiteflies, or spider mites are munching on the tender bits and leaving honeydew behind. Blast them off with a strong spray of water first, then treat any stragglers with insecticidal soap. Keep the watering steady, invite a few beneficial insects in, and the next batch won't get far.
Fix:
- Rinse plants with a strong spray of water
- Apply insecticidal soap to affected areas
- Encourage beneficial insects
Toxicity
Got pets or little ones? Good news: scarlet sage is totally non-toxic. The ASPCA has it down as safe for cats and dogs, and there's nothing in it to worry about for other animals, livestock, or kids. So go ahead and plant it wherever the family hangs out.
Safe for
People · Cats · Dogs · Horses · Rabbits · Livestock · Birds
Cats None
No need to stress about the cat, scarlet sage is on the ASPCA's safe list. If one eats a whole bunch it might throw up, like with any plant, but there's nothing toxic going on.
Dogs None
Dogs are fine around this salvia too, and the ASPCA calls it non-toxic to them. A dog that scarfs down a lot of leaves could get a bit of a tummy ache, but that's true of most greenery.
Horses Safe
Horses have nothing to fear here, there's nothing poisonous in it, so it's no worry in a pasture or along a border.
Rabbits Safe
Rabbits can nibble the leaves and flowers no problem. Just ease it into their diet slowly, like you would any new green, so their tummy adjusts.
Livestock Safe
Cattle, goats, and sheep? They're all fine, since there's nothing toxic in this salvia if they graze on it.
Birds Safe
Birds are safe around it, and the flowers pull in pollinators all season. Backyard chickens can peck away without any trouble.
People Safe
And people? Scarlet sage isn't poisonous to people either, since it's grown for the flowers, not for eating. So there's no need to panic if a kid handles it or gives it a taste.
Varieties
There are loads of named salvias out there, but only a few show up again and again at the garden center. Those are the ones worth knowing about.
Bonfire
Bonfire lines up neat scarlet spikes on upright plants that hit about 26 inches tall.
Salsa Series
The Salsa Series stays nice and compact at 12 to 14 inches in scarlet and mixed colors, and it takes the Southeast's heat in stride.
Vista Group
The Vista Group blooms early on little dwarf bedding plants and comes in all sorts of colors.
Salvia farinacea (mealycup sage)
Then there's Salvia farinacea, or mealycup sage, with blue-to-violet or white spikes on 1 to 2 foot clumps, and it's often grown as an annual too.
How to propagate
Want more salvia? It's easy. You can either start a fresh batch from seed, or take a few cuttings to keep a plant you love going over winter.
SeedModerate
Start indoors 6 to 8 weeks before the last frost; surface sow because light aids germination · Several weeks to germinate and grow on before transplanting after frost
Most folks just grow salvia from seed, sown indoors about 6 to 8 weeks before the last frost. Press the seeds onto the surface and leave them uncovered, since light's what gets them going. Keep the tray warm and bright, and give it a few weeks, the seedlings need that time to sprout and grow before they head outdoors once frost is done.
Stem cuttingsModerate
Take softwood cuttings in late summer to overwinter plants indoors · A few weeks to root
Cuttings are a handy way to hang onto a plant you really like. Take softwood cuttings in late summer, let them root over a few weeks, and keep the little plants in a bright, cool spot until spring rolls around.
Myths
That scarlet sage in the flower bed is the same thing as the psychoactive Salvia divinorum.
Nope, they just happen to share a genus name. The garden annuals, Salvia splendens and Salvia farinacea, are all about the flowers, and they've got none of the effects people link to Salvia divinorum.
Once salvia's settled in, you can quit watering because it handles drought.
Not really, because annual scarlet sage is not drought tolerant at all. It blooms best when the soil's warm, well-drained, and evenly moist, so let it dry out and those spikes fade in no time.