Gardenia (cape jasmine)
Gardenia jasminoides · Coffee family (Rubiaceae)
| Hardiness zones | 7 to 11 |
|---|---|
| Sun | part shade |
| Water | moderate |
| Life cycle | perennial |
| Frost | Half-hardy: takes a light frost |
| Soil pH | 5.0–6.5 |
About Gardenia (cape jasmine)
Gardenia is an evergreen shrub from southern China and Japan grown for waxy white flowers with a heavy, sweet scent in late spring and summer. It needs acid soil and steady care, and whiteflies are a common problem. Hardier cultivars like 'Kleim's Hardy' and 'Jubilation' extend it into zone 7.
Older cultivars are reliable in zone 8; newer ones survive zone 7 (Clemson); NC State lists 7b-11b.
When to plant
Timing is counted from your average last spring frost (and first fall frost). Sow & Tell works out the actual dates for your ZIP code.
Fall is the best time to plant; gardenias resent root disturbance, so place them once (Clemson). Mulch 2-3 inches and water weekly in summer droughts, ideally by drip. In central and south Florida, grafted plants resist root-knot nematodes but are less cold-hardy (UF/IFAS).
Soil
Moist, well-drained, acid soil rich in organic matter (pH below 6.0, Clemson; 5.0-6.5, UF/IFAS); grow it in a pot where your soil is alkaline.
Amend with compost or peat moss for a rich, well-drained soil with pH 5.0-6.5; use a container if your soil is alkaline (UF/IFAS).
Feeding
- Spring, once frost danger has passed: acid-forming, slow-release azalea fertilizer with about a 2-1-1 ratio. Follow the label and a soil test; water in (Clemson).
- About 6 weeks later: the same fertilizer. A second light feeding (Clemson). In Florida, UF/IFAS adds a September-October feeding.
Don't fertilize in fall in the Carolinas (Clemson). Yellow leaves often mean iron deficiency from high pH. Whiteflies and sooty mold are common on stressed plants.
Harvest
Main bloom is May-June with scattered flowers through summer (Clemson). Prune after flowering ends, removing straggly branches and faded flowers; in Florida finish before October to keep next year's buds (UF/IFAS). Bud drop comes from dry air, too much or too little water, or low light.
Varieties (9)
Extension sources document 9 gardenia cultivars.
| Variety | Type | Days | Notes |
|---|---|---|---|
| August Beauty | Gardenia (G. jasminoides) | 4-6 ft; double 3-inch flowers over a long season. | |
| Crown Jewel | Gardenia (G. jasminoides) | Spreading, about 2 ft tall and 4 ft wide; very cold hardy double. | |
| Jubilation | Gardenia (G. jasminoides) | Compact, rounded shrub with very fragrant 2-4 inch double flowers; drought tolerant once settled. | |
| Kleim's Hardy | Gardenia (G. jasminoides) | About 2-3 ft; single, star-shaped ivory flowers about 2 inches across with gold stamens. | |
| Lynn Lowrey | Gardenia (G. jasminoides) | Fragrant flowers with yellow centers. | |
| Mystery | Gardenia (G. jasminoides) | 4-6 ft, sometimes 8; very large double flowers. | |
| Scentsation | Gardenia (G. jasminoides) | Very fragrant. | |
| White Gem | Gardenia (G. jasminoides) | Dwarf, about 2 ft; good in containers. | |
| Radicans | Gardenia (G. jasminoides), dwarf groundcover | Low and spreading, 2-3 ft tall; very fragrant 1-2 inch double flowers. |
Pests to watch for
Whiteflies, Aphids, Scale insects, Mealybugs, Thrips, Root-knot nematodes, Tobacco budworm (geranium or petunia budworm)
Diseases and problems
Sooty mold, Root rot, Iron chlorosis
In the kitchen
NC State notes the orange fruit is used for a yellow food and fabric dye.
Safety: NC State rates it low severity: eating it can cause mild vomiting, diarrhea or hives.
Pets: Toxic to dogs, cats and horses (ASPCA): geniposide and gardenoside can cause mild vomiting, diarrhea and hives.
Sources
Photo: Photo: Alpsdake, CC BY-SA 3.0, via Wikimedia Commons (CC BY-SA 3.0). Photo resized for the web.
Planting dates and advice are general guidance; check with your local Cooperative Extension office for your area.