Ornamental · Caryophyllaceae
Carnation
Dianthus caryophyllus
Offer it cool air, full sun, and sharp drainage, and the carnation returns the favor with fragrant, ruffled bloom.
Full sun
USDA 4–9
0–4 ft · 0.2–1.2 m
Overview
Carnations and the garden pinks alongside them sit within the dianthus family, cultivated for ages for their ruffled, clove-scented flowers. The range stretches from low cushions only a few inches high to long-stemmed border forms made for cutting, which gives you one shape for the edge of a bed and another for the table.
At heart these are cool-weather plants, most content in full sun with their roots set into gritty, fast-draining soil. They favor the alkaline end of things, accepting a pH anywhere from 6.0 to 8.0, a preference that quietly separates them from much of what surrounds them in a border.
Easy to grow yet short-lived, they tend to fade after a handful of seasons unless you keep replacements on the way. Feed with restraint, keep the crowns dry, and the return is weeks of fragrant bloom carrying from late spring into summer.
Care
The short version: full sun, cool conditions, and gritty, well-drained soil leaning neutral to alkaline. Hold the soil evenly moist while never letting it turn soggy, keep feeding light, and deadhead spent blooms so fresh flowers keep arriving.
Light
Carnations look for full sun, a solid six hours or more each day, to flower at their fullest and hold themselves upright. A little afternoon shade is welcome where summers heat up, easing the warmth they would rather avoid.
Water
Aim for soil that stays evenly moist but never soggy, and reach for the hose through any long dry stretch. Standing wet is the quickest route to crown rot, so let the surface dry between waterings and keep the crown itself on the drier side.
Soil
Set them into gritty, well-drained loam with a little organic matter mixed through. Unusually, carnations prefer neutral to slightly alkaline ground, a pH of 6.0 to 8.0, and crisp drainage outweighs richness every time.
Humidity
Everyday outdoor air is all they ask, so there is no figure to chase here. Airflow matters more than humidity, because foliage that sits crowded and damp is just what rust looks for.
Feeding
Keep feeding light across the growing season and resist any push to give more. Too much fertilizer grows a floppy, gappy plant on weak stems rather than a fuller display of flowers.
Pruning
Deadhead the spent blooms to keep more arriving, and pinch out the tips early to encourage bushier growth. Once the main flush has passed, shear the mat-forming pinks back to coax a light scatter of repeat bloom.
Size & spacing
Forms run from low cushions near 6 inches (15 cm) tall to border types touching 4 feet (120 cm), spreading 6 to 30 inches (15 to 76 cm) wide. Give each plant space so air can circulate and rust keeps its distance.
When to plant
Carnations keep to the cooler edge of the season. Sow seed indoors in late winter, move plants outside in spring after hard frost has passed, and watch for fragrant bloom from late spring through summer, drawn out longer when you stay on top of deadheading.
Northern hemisphere
Southern hemisphere
Typical months for a temperate climate: start earlier in warm zones, later where spring frosts linger.
- Sow: Late winter to early spring, about 8 weeks before last frost
- Plant: Spring after danger of hard frost; mat-forming pinks can also be set out in early spring
- Harvest: Late spring through summer (roughly May to July), prolonged by deadheading
Hardiness
USDA hardiness zones: 4–9
Temperature: down to -34°C
Troubleshooting
Carnation problems tend to begin either at the roots or in summer warmth. Keep an eye on the crown, the lower stems, and the fresh growth, and you can intervene before something minor takes hold. Find the match below, then act while action still counts.
A dark, soft stem base as the plant gives way
The cause is crown or root rot, brought on by soil that holds too much moisture, and it tends to set in across a damp winter. Once the crown has gone soft and dark the plant is past rescue, so lift it and throw it out. Sort the drainage and pull back on watering before anything new goes in its place.
Fix:
- Remove and discard severely affected plants
- Improve soil drainage
- Reduce watering and avoid wet, soggy soil
Rust-toned spotting along the foliage and stems
What you are seeing is rust, a fungal problem that settles in when leaves stay damp and the air sits still around the plant. Strip away the marked foliage the moment it appears, open up some breathing space between plants, and direct your watering at the soil so the leaves stay dry.
Fix:
- Remove and discard affected foliage
- Improve air circulation by spacing plants
- Avoid overhead watering to keep foliage dry
Fading, yellowing leaves through a summer heat spell
Warmth is the carnation's weak point, so a plant that slumps during a hot stretch is almost always reacting to heat stress, not a bug or a blight. Offer it some afternoon shade, hold the soil evenly moist through the worst days, and lean on heat-tolerant pinks such as the cheddar types if your patch sits in a warm climate.
Fix:
- Provide afternoon shade in hot regions
- Maintain even soil moisture during heat
- Choose heat-tolerant pinks such as cheddar pinks in warm climates
Twisted new shoots dotted with tiny insects
Those small soft bodies massed on the buds and stems are aphids, and the tacky coating they leave is honeydew. Knock them loose with a firm spray of water, prune away any shoots that are heavily covered, and turn to insecticidal soap if they return. Keep feeding modest as well, because the soft new growth they crave is precisely what overfeeding produces.
Fix:
- Spray plants with a strong stream of water
- Remove heavily infested shoots
- Use insecticidal soap if needed
Toxicity
Carnations rate as only mildly toxic, which makes them an easy plant to live with. A curious cat or dog that chews a leaf might feel a passing stomach upset and the sap can raise a mild skin rash, yet the petals turn up as an edible garnish for people. Keep pets from treating the foliage as a snack and there is little cause for concern.
Toxic to
Cats · Dogs · Horses · Rabbits · Livestock · Birds
Safe for
People
Cats Mild
Should a cat sample a leaf or flower, expect a little drooling, vomiting, or diarrhea, and any contact with the sap can raise a faint skin rash. None of it is serious, and the symptoms usually settle on their own.
Dogs Mild
A dog responds in the same fashion, with some vomiting or a loose stool after a nibble and now and then a touch of skin irritation from the sap. None of it is harmful, though a vet call makes sense if the trouble lingers.
Horses Caution
No case of poisoning in horses has been recorded, but the same mild irritant might unsettle the stomach. Keeping them away from grazing on it is the safer choice.
Rabbits Caution
No harm to rabbits has been noted, yet the plant is not feed for them either, which makes it best left off their plate.
Livestock Caution
Cattle, goats, and sheep show no recorded poisoning from carnations, but the irritant compound might still bring on mild stomach upset should they graze a stand of it.
Birds Caution
Carnations carry no warning as a bird hazard, though so little is understood about their effect on birds that keeping pet birds clear of the foliage is the prudent move.
People Petals safe
Edible petals that often appear as a garnish mean the carnation holds no real danger for people. The single caveat is the sap, which can leave sensitive skin slightly irritated, so a rinse of the hands after a long session of handling is sensible.
Sap may cause mild skin irritation in sensitive people; wash hands after handling.
Helpline numbers
United States
ASPCA Animal Poison Control: (888) 426-4435 (fee applies)
United Kingdom
Animal PoisonLine: 01202 509000 (fee applies)
Australia
Animal Poisons Helpline: 1300 869 738
Varieties
Carnations and pinks arrive in hundreds of forms, from tall florist stems to low fragrant mats. The handful below are the ones worth recognizing by name.
Clarion
A border carnation lifting clear yellow double flowers on sturdy upright stems above gray-silver foliage.
Bath's Pink
A mat-forming cheddar pink whose fragrant fringed soft-pink blooms take heat, humidity, and drought in stride better than most dianthus.
Firewitch
A cheddar pink valued for vivid magenta single flowers, blue-gray foliage, strong fragrance, and genuine cold hardiness.
How to propagate
Since carnations do not last long, it makes sense to keep fresh plants arriving, whether by splitting a tired clump or rooting a few cuttings.
Stem cuttingsModerate
Take terminal cuttings in early summer · Several weeks to root
To reproduce a named cultivar you turn to cuttings, since seed will not breed those true. Take a healthy shoot tip in early summer, set it into moist mix, and over several weeks it roots into a plant that matches its parent exactly.
DivisionEasy
Early spring as new growth begins · One growing season
Given how short-lived carnations are, dividing the clumps every few years keeps a planting alive. Lift and split them in early spring as new growth appears, and the divisions take hold across a single growing season.
Myths
Carnations are tough plants that thrive in hot summer climates.
The truth runs the opposite way. Carnations favor cool weather and labor through high heat, which makes them an uncertain choice for hot southern gardens. Reach for heat-tolerant pinks like the cheddar types if your summers run warm.
Feed carnations heavily and you'll get the best blooms.
Heap on the fertilizer and the result is tall, floppy stems and bare gaps in the plant, not a fuller show of flowers. A light hand at feeding gives you the sturdiest growth and the best bloom.