Gardenia (Gardenia jasminoides) care

Flowering · fussy to keep

Gardenia (Gardenia jasminoides) wants bright light with some direct sun. Water it every 5 days. Keep evenly damp with rainwater or filtered water. Hard tap water will yellow the leaves within a couple of months whatever else you do. Pot it in ericaceous (acid) compost — this is not optional. An ericaceous or acid-loving plant feed every two weeks in spring and summer, and repot once a year. Humidity: above 60%, consistently. Mildly toxic to cats and dogs; causes vomiting and diarrhoea.

The gardenia: glossy dark leaves and thick white flowers with one of the strongest scents of any plant. It is also the most demanding plant on this list — it needs acid soil, rainwater, humidity above 60% and absolute consistency, and it drops every bud if any of those slip.

Quick facts

Water: Water every 5 days. Keep evenly damp with rainwater or filtered water. Hard tap water will yellow the leaves within a couple of months whatever else you do.
Light: Bright light with some direct sun.
Humidity: Above 60%, consistently.
Soil: Ericaceous (acid) compost — this is not optional.
Feeding: An ericaceous or acid-loving plant feed every two weeks in spring and summer.
Repotting: Repot once a year.
Toxic to pets: Mildly toxic to cats and dogs; causes vomiting and diarrhoea.
Difficulty: Fussy.
Mature size: 50–100 cm indoors.
Native to: Southern China, Taiwan and Japan.

Watering a Gardenia

Water every 5 days. Keep evenly damp with rainwater or filtered water. Hard tap water will yellow the leaves within a couple of months whatever else you do.

That cadence is the one PlantParlour sets for this species when you name it, and it is deliberately on the cautious side — a plant that asks a day early is safer than one that asks a day late. Log each watering and the reminder moves with the plant rather than with the calendar.

Light

Bright light with a few hours of direct sun. Gardenias are demanding plants and light is the least of it.

Humidity and temperature

Above 60%, consistently. Central heating in winter is what turns a comfortable room into a dry one, and it is the usual reason an established plant suddenly browns at the edges or picks up spider mites.

Soil and potting

Gardenias need acid soil, pH 5 to 6. In ordinary compost or with hard tap water they cannot take up iron and go yellow between the veins. Use ericaceous compost and rainwater.

Feeding

An ericaceous or acid-loving plant feed every two weeks in spring and summer. Stop feeding in autumn and start again when you see new growth in spring — feeding a plant that isn't growing just builds up salts in the pot.

Repotting

Repot once a year. Every second spring, into fresh ericaceous compost.

Common problems

Yellow leaves with green veins
Iron deficiency from soil or water that is too alkaline — the classic gardenia problem.

Fix: Repot into ericaceous compost, water with rainwater, and feed with a sequestered iron product.
Buds dropping before opening
A change in temperature, light, watering or humidity. Gardenias object to all of them.

Fix: Keep everything constant once buds form, and humidity above 60%.
Sticky leaves, black sooty mould
Scale or mealybugs.

Fix: Treat weekly for a month and wipe the mould off.

Propagation

Semi-ripe cuttings in summer with bottom heat, under cover. Not easy.

A cutting taken in PlantParlour keeps its link to the plant it came from, so a propagation years later still traces back to the mother plant — which is the point if you ever sell or trade it.

Toxicity and safety

Mildly toxic to cats and dogs; causes vomiting and diarrhoea.

Questions people ask

How often should you water a Gardenia?

Water every 5 days as a starting point — that is the cadence PlantParlour sets for Gardenia jasminoides. Keep evenly damp with rainwater or filtered water. Hard tap water will yellow the leaves within a couple of months whatever else you do. Light, pot size and the time of year all move that number, so treat it as a reminder to go and check rather than a rule.

How much light does a Gardenia need?