Gardenia care guide

The gardenia has glossy, dark green leaves and creamy white flowers with a rich, sweet scent. It is one of the most loved flowering shrubs, and one of the fussiest to grow indoors. It wants bright light, acid soil, moist air, steady water, and cool nights. Give it those, and it rewards you with flowers. Miss one, and it drops its buds.

Light

Give it bright light. An east window is ideal. A south or west window with a sheer curtain works too. It needs at least four hours of bright light a day to bloom. A few hours of soft morning sun is good.

Hot afternoon sun through glass scorches the leaves. In low light, it grows but does not bloom.

Water

Water when the top 2 cm (1 in) of soil is dry. Water until it drains, then empty the saucer. Keep the soil moist, never soggy, and never bone dry. In winter, it needs water less often.

Use rainwater or room-temperature water. Cold water shocks the roots. Hard tap water raises the soil pH over time, which yellows the leaves. Read how to tell if a houseplant is overwatered or underwatered.

Soil and potting

Gardenias need acidic soil. Use a potting mix made for azaleas, camellias, or acid-loving plants.

Repot every two to three years in spring, one size up. Do not repot while it has buds. See how to repot a houseplant step by step.

Humidity and temperature

Gardenias need moist air. Aim for 50% humidity or higher. Dry air is a top cause of bud drop. A humidifier helps most. Keep it away from heat vents and wood stoves.

Cool nights help it set buds. Keep it at 18 to 24°C (65 to 75°F) by day and 15 to 18°C (60 to 65°F) at night. Warm nights, above about 21°C (70°F), stop buds from forming.

Feeding

Feed every two weeks in spring and summer with an acid fertilizer for azaleas and camellias, at half strength. Skip feeding in fall and winter.

Why buds drop

Gardenias drop buds when anything changes. Common causes:

• The pot was moved or turned
• Dry air
• Warm nights
• Soil that dried out or stayed soggy
• Not enough light

Pick a good spot and leave it there. Keep care steady while buds form.

Yellow leaves

Yellow leaves with green veins mean it cannot take up iron. The soil is not acidic enough. Water with rainwater, feed with an acid fertilizer, or add a chelated iron product.

Older leaves that turn all yellow and drop now and then are normal. Many yellow leaves at once point to too much water, cold, or a sudden change.

Pruning

Prune right after it finishes blooming. Cut back long stems to shape it. Cut just above a leaf. Pinch off spent flowers. Do not prune in fall or winter, or you cut off next year’s buds.

Propagation

In late spring or summer, cut a stem tip 10 to 12 cm (4 to 5 in) long. Pull off the lower leaves. Dip the end in rooting hormone. Push it into moist, acidic mix. Cover it with a clear bag and keep it warm and in bright indirect light. Roots take four to eight weeks.

Problems

What you see	Most likely cause
Buds drop before opening	Dry air, warm nights, a move, or uneven water
Yellow leaves with green veins	Soil not acidic enough
Many yellow leaves at once	Too much water, cold, or a sudden change
Brown leaf edges	Dry air, or fertilizer buildup
No buds	Not enough light, or warm nights
Black, sooty coating on leaves	Sooty mold from pests
Fine webbing under leaves	Spider mites

Pests

Spider mites, mealybugs, aphids, whiteflies, and scale all like gardenias. Check under the leaves and along the stems every week. Rinse the leaves in the shower to knock pests off. Black sooty mold grows on the sticky waste some pests leave.

Pet safety

The ASPCA lists gardenia as toxic to cats and dogs. It can cause mild vomiting and diarrhea. Keep it out of reach.

Varieties

• Gardenia jasminoides ‘Veitchii’ blooms on and off for much of the year. It is the best choice for indoors.
• Gardenia jasminoides ‘Radicans’ is a dwarf with small leaves and small flowers.
• Gardenia jasminoides ‘August Beauty’ blooms over a long season with large flowers.
• Gardenia jasminoides ‘Kleim’s Hardy’ has single, star-shaped flowers. It is one of the more cold-tolerant forms for gardens.