Ornamental · Caryophyllaceae
Carnation
Dianthus caryophyllus
Hand it cool air, full sun, and sharp drainage, and the carnation gives back fragrant, ruffled bloom.
Full sun
USDA 4–9
0–4 ft · 0.2–1.2 m
Overview
Carnations, along with their relatives the garden pinks, sit in the dianthus group, and people have grown them for ages for those ruffled, clove-scented flowers. Some stay as low cushions only a few inches high while others put up long stems made for cutting, so you've got one shape for the front of the bed and another for the vase.
At heart these are cool-weather plants, most content in full sun with their roots tucked into gritty, fast-draining soil. They actually prefer the alkaline side and handle a pH anywhere from 6.0 to 8.0, which makes them stand out from most of their bed-mates.
They're simple to grow but they don't stick around long, petering out after a few seasons unless you keep new plants on the way. Go light with the feeding, keep those crowns dry, and you'll be paid back with weeks of fragrant bloom running from late spring into summer.
Care
The short version: full sun, cool conditions, and gritty, well-drained soil that leans neutral to alkaline. Keep the soil evenly moist but never soggy, feed only lightly, and deadhead spent blooms to keep the flowers coming.
Light
Carnations are after full sun, ideally six hours or more each day, so they bloom well and hold themselves up instead of flopping. Where summers get hot they'll accept a bit of afternoon shade, which also gives them a break from the heat they don't enjoy.
Water
Go for soil that stays evenly moist but never soggy, and give them a drink through any long dry spell. Sitting in wet soil is the quickest route to crown rot, so let the top dry off between waterings and keep the crown itself dry.
Soil
Set them in gritty, well-drained loam with a bit of organic matter mixed through. Carnations are a little unusual in that they like neutral to slightly alkaline ground, a pH of 6.0 to 8.0, and good sharp drainage counts for more than rich soil ever will.
Humidity
Regular outdoor air is all they need, so don't go chasing a target number. Airflow matters more than humidity here, because crowded, damp leaves are exactly what lets rust get a foothold.
Feeding
Keep the feeding light across the growing season and skip the temptation to overdo it. Too much fertilizer just builds a floppy, gappy plant with weak stems instead of giving you more flowers.
Pruning
Deadhead the spent blooms so fresh ones keep arriving, and pinch the growing tips off early to encourage bushier growth. Once the main flush is done, shear the mat-forming pinks back and you'll catch a scattering of repeat bloom.
Size & spacing
These run from low cushions around 6 inches (15 cm) tall up to border types hitting 4 feet (120 cm), with a spread of 6 to 30 inches (15 to 76 cm) across. Leave each plant some space so air can move and rust stays out of the picture.
When to plant
Carnations track the cooler end of the season. Get your seed going indoors in late winter, move plants outside in spring once hard frost is behind you, and watch for fragrant bloom from late spring through summer, which runs longer the more you deadhead.
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
Most carnation trouble kicks off either down at the roots or in the heat. Keep an eye on the crown, the lower stems, and the new growth, and you can jump in before a small issue gets bigger. Find what matches below, then deal with it while it can still do some good.
Dark, mushy stem base with the plant falling over
You're dealing with crown or root rot, which shows up when soil holds too much water, and a damp winter is often the trigger. Once the crown goes soft and dark there's nothing to bring back, so pull the plant and toss it. Sort out the drainage and dial back the watering first, then try again.
Fix:
- Remove and discard severely affected plants
- Improve soil drainage
- Reduce watering and avoid wet, soggy soil
Rusty orange bumps showing up on leaves and stems
What you're looking at is rust, a fungus that moves in when leaves stay damp and the air sits still. Strip off the spotted leaves the moment they appear, open up some breathing room between your plants, and point the water at the soil so the foliage stays dry.
Fix:
- Remove and discard affected foliage
- Improve air circulation by spacing plants
- Avoid overhead watering to keep foliage dry
Leaves going yellow and the plant slipping in summer heat
Heat is rough on carnations, so a plant that sags during a warm stretch is almost always feeling heat stress and not bugs or disease. Move it into some afternoon shade, keep the soil evenly damp while the heat lasts, and if your area runs warm, lean on heat-tolerant pinks such as the cheddar types.
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 covered in tiny bugs
Those little soft bodies bunched up on the buds and stems are aphids, and that sticky coating they leave is called honeydew. Knock them loose with a hard spray of water, trim away any shoots that are really crawling, and bring in insecticidal soap if they won't quit. Keep the feeding light too, because all that soft new growth is what pulls them in.
Fix:
- Spray plants with a strong stream of water
- Remove heavily infested shoots
- Use insecticidal soap if needed
Toxicity
Carnations are just mildly toxic, so they're a pretty low-risk plant to have around. A nosy cat or dog that chews on the leaves might get a quick upset stomach, and the sap can leave a mild rash, but the petals even show up as an edible garnish for people. Keep your pets from snacking on the foliage and there's really not much to worry about.
Toxic to
Cats · Dogs · Horses · Rabbits · Livestock · Birds
Safe for
People
Cats Mild
If a cat takes a bite of the leaves or flowers, expect maybe some drooling, vomiting, or a touch of diarrhea, and rubbing against the sap can bring on a mild rash. None of it is serious, and it usually settles by itself.
Dogs Mild
It goes pretty much the same for dogs: a chew might bring on a bit of vomiting or soft stool, and the sap can cause some mild skin irritation. Nothing risky, but if it lingers, give the vet a quick call.
Horses Caution
Nobody's reported actual poisoning in horses, but that same mild irritant could still unsettle the gut. Keeping them from grazing on it is the safe move.
Rabbits Caution
There's no record of rabbits being harmed, yet it isn't something they should be eating either, so it's better kept off their plate.
Livestock Caution
Cattle, goats, and sheep don't have any logged cases of carnation poisoning, but that irritant compound might still bring on a mild stomach ache if they graze a clump.
Birds Caution
Carnations aren't on any list as a bird danger, though so little is known about their effect on birds that keeping pet birds clear of the leaves just makes sense.
People Petals safe
Those petals are edible and show up as a garnish, so there's no real danger to people here. The one thing to watch is that the sap can leave sensitive skin a little irritated, so rinse up after a long stretch of handling.
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 turn up in hundreds of shapes, from tall florist types right down to low fragrant mats. Here are a few that are well worth knowing by name.
Clarion
This border carnation holds clear yellow double flowers on sturdy upright stems, set off by gray-silver foliage.
Bath's Pink
A mat-forming cheddar pink whose fragrant fringed soft-pink blooms handle heat, humidity, and drought better than most dianthus can.
Firewitch
Gardeners love this cheddar pink for its bright magenta single flowers, blue-gray foliage, strong scent, and genuine cold hardiness.
How to propagate
Carnations don't live long, so it makes sense to keep new plants on the go, whether that means splitting an old clump or rooting a handful of cuttings.
Stem cuttingsModerate
Take terminal cuttings in early summer · Several weeks to root
Want to copy a named cultivar? Cuttings are how you do it, since seed won't give you a true match. Clip a healthy shoot tip in early summer, pop it into moist mix, and after several weeks to root you'll have a plant just like the one it came from.
DivisionEasy
Early spring as new growth begins · One growing season
Since carnations don't live long, dividing up the clumps every few years keeps the plants around. Dig and split them in early spring as new growth shows, and the divisions get comfortable over a single growing season.
Myths
Carnations are tough plants that thrive in hot summer climates.
Actually the opposite is true. Carnations love cool weather and have a hard time when it gets hot, so they're an iffy choice for warm 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.
Load on the fertilizer and what you get is tall, floppy stems and a gappy plant, not extra flowers. A light hand at feeding gives you the sturdiest growth and the best bloom.