Gardenia
Gardenia jasminoides
Famously particular: hard water yellows the leaves, and a swing in temperature drops the buds before they open.
- Type
- Shrub · Perennial
- Botanical family
- Mixed / other
- Foliage color
- Green
- Flower color
- White
- Sunlight
- Partial shade to full sun, with shelter from harsh midday sun in hot climates.
- Watering
- Keep it moist but never waterlogged, and use rainwater or soft water.
- Feeding
- Ericaceous feed every three to four weeks through the growing season.
- Frost tolerant
- Yes
- Flowering
- June
- Pruning
- Trim lightly after flowering, and take out dead wood in spring.
- Apr–Jun Bud Break
- Jun–Sep Flowering
- Sep–Dec Growing
- Jan–Apr Growing
- Plant spacing
- 3 ft 11 in
- In-row spacing
- 3 ft 11 in
- Between rows
- 4 ft 11 in
- Square-foot density
- Not suited to SFG
- Root system
- A fine surface mat, and nothing below it
- Working depth
- 4–12 in
- Can reach
- 18 in down where the soil allows
- Spread
- 4–6 ft across, about 1–1.5× the width of the plant
- Shallowest pot
- 16 in of soil
Hair-fine roots in a shallow felt, with no deep anchor to fall back on. It cannot chase water, so it is the first casualty of a drought and the first thing killed by a hoe. Mulch it, never cultivate around it, and never let it go dry in its first two summers.
The habit is Gardenia’s own; the figures are what that habit usually comes to at this size, not a measurement of this species. Roots follow the soil either way: a compacted pan, a high water table or heavy clay stops them well short of any of it, and deep open ground lets them go further.
- Cats and dogs
- Recorded toxic
Recorded as toxic to cats and dogs by ASPCA.
Same species also filed as Cape Jasmine.
- Mealybugs White cottony sap-suckers that gather in leaf axils and along stems, mostly on houseplants and under glass. Dab colonies with a cotton swab dipped in soapy water and isolate affected plants.
- Scale insects Immobile brown or white bumps fixed to stems and leaf undersides, sucking sap and weakening growth. Wipe off with a damp cloth or dab with horticultural soap; watch for the sooty mold that follows.
- Spider mites Near-invisible mites that stipple leaves yellow and spin fine webbing in hot, dry conditions. Raise humidity, mist and rinse foliage, and introduce predatory mites under glass.
- Sooty mold Sooty mold over the leaves
- Iron chlorosis Chlorosis — leaves yellowing where alkaline soil locks up the iron
- Bud drop, brought on by swings in temperature or dry air
Beneficial predators that hunt this plant's pests — grow their favourite flowers nearby to recruit them. companion plant
- Ladybird (lady beetle) Coccinellidae
The gardener’s favorite ally: adults and their alligator-shaped larvae each eat thousands of aphids, plus scale, mealybugs, and other soft-bodied sap-suckers. Grow flat, open flowers for the adults and never spray a colony that ladybird larvae are already working.
- Green lacewing Chrysoperla carnea
Its bristly larvae — "aphid lions" — impale aphids, mealybugs, thrips, and mite colonies, eating hundreds a week. Adults feed on nectar and pollen from small open flowers and overwinter in hollow stems left standing.
- Hoverfly Syrphidae
Bee-mimicking flies whose legless larvae graze aphid colonies clean while the adults pollinate. A ribbon of shallow, nectar-rich flowers kept in bloom all season recruits wave after wave of them.
- Big-eyed bug Geocoris spp.Hunts Spider mites
A stubby 3 mm bug with enormous wrap-around eyes, working the soil surface and the low foliage for aphids, mites, thrips and insect eggs. It is the main natural check on chinch bugs in a lawn and it is killed outright by insecticide.
- Minute pirate bug Orius spp.Hunts Spider mites
A pinhead-sized true bug that is the best natural check on thrips, and happily spears aphids, mites, and insect eggs too. It needs pollen when prey is scarce, so keep something flowering nearby.
- Predatory mites Phytoseiulus & AmblyseiusHunts Spider mites
Fast orange mites that hunt spider mites egg-by-egg, and cousins that clear thrips and fungus-gnat larvae. Sold as a biological control for greenhouses; outdoors they follow humidity — mist and mulch, don’t dust with sulfur.
- Rove beetle StaphylinidaeHunts Spider mites
Slim, quick beetles with short wing cases that hunt in soil and litter, taking root-fly eggs and larvae, fungus-gnat larvae, and mites. Mulch and undisturbed ground keep them resident year-round.
Azalea, Camellia, Rhododendron, Japanese Pieris, Ferns
Shrubs, like this one.
The Cottage Garden Companion — the gardener's herbarium at cottagegardencompanion.com