No plant expresses the grace of the South better than gardenia. Intensely fragrant white blossoms contrast beautifully with shiny, leathery, dark green leaves. Double forms are a classic choice for corsages.
Gardenias are lovely in flower borders and also do well in large pots on decks and patios; gardeners in cold-winter areas can grow them in cool greenhouses.
G. jasminoides. COMMON GARDENIA, CAPE JASMINE. Zones LS, CS, TS; USDA 8-11, except as noted. Native to China, Taiwan, Japan. Glossy, bright green leaves and usually double white flowers to 3 in. across. Most are hardy to about 10F; they will survive 0F but are likely to die back to roots.
The many selections are useful in containers or raised beds, as hedges, espaliers, low screens, or single plants.
'Aimee' ('First Love'). Somewhat larger shrub than 'August Beauty', with larger double flowers. Spring bloom.
'August Beauty'. Grows 46 ft. high and 34 ft. wide. Blooms heavily midspring into fall. Large double flowers.
'Chuck Hayes'. Extra-hardy type, possibly as hardy as 'Kleim's Hardy'. To 4 ft. high and wide. Double flowers in summer, heavy rebloom in fall.
'Crown Jewel'. Selected from a cross between 'Kleim's Hardy' and 'Chuck Hayes'. Grows 2212 ft. tall and 4 ft. wide, with fully double blooms over a long period. One of the hardiest selections listed here, surviving -10F.
'Golden Magic'. Reaches 3 ft. tall, 2 ft. wide in 2 to 3 years, eventually larger. Extra-full flowers open white, gradually age to deep golden yellow. Blooms from spring through summer, peaking in midspring.
'Grif's Select'. Compact, 34 ft. tall and wide; profuse single flowers in late spring and early summer, red seed capsules in fall. Hardy to about 5F.
'Jubilation'. Compact grower to 34 ft. tall and wide. Very fragrant blooms are produced heavily in spring and again in fall.
'Kimura Shikazaki' ('Four Seasons'). Compact plant 23 ft. tall. Flowers similar to those of 'Veitchii', but slightly less fragrant. Extremely long bloom seasonspring to fall.
'Kleim's Hardy'. For cold- winter areas; hardy to 0F. To 23 ft. high and wide. Single flowers in summer. Grow in a wind-protected site.
'Miami Supreme'. Grows to 10 ft. tall and wide, with large double flowers (46 in. wide) in spring, periodic flowering through summer. Fast grower. Most popular selection for South Florida.
'Mystery'. Best-known selection. Bears 4- to 5-in. double flowers from mid- to late spring or longer. Tends to be rangy and needs pruning to keep it neat. Can reach 68 ft. high and wide.
'Pinwheel'. An interesting variation on the gardenia theme. Each petal is rolled at the base and flares at the tip, giving the flowers the appearance of a pinwheel. Intensely fragrant. Grows 4 ft. tall and wide, with good repeat bloom from late spring well into fall. Reportedly hardy to -10F.
'Radicans' ('Prostrata'). Grows 612 in. tall and spreads to 23 ft., with small leaves; inch-wide double flowers bloom in sum- mer. Good for small-scale ground cover or pots. Not as cold hardy as the species; not well suited to Middle South. 'Radicans Variegata' ('Prostrata Variegata') has gray-green leaves with white markings.
'Shooting Star'. Upright grower to 68 ft. tall and wide, with large leaves and single flowers in late spring and early summer. Hardy to 0F.
'Veitchii'. Compact, reliable grower to 312412 ft. tall and 6 ft. wide. Blooms prolifically from midspring into fall (and sometimes even during warm winters), bearing fully double 1- to 112-in. flowers.
'White Gem'. At just 12 ft. tall and wide, this selection is useful for edgings, containers, or raised beds, where the fragrance of its single, creamy white summer flowers can be appreciated.
G. thunbergia. STARRY GARDENIA. Zones TS; USDA 10-11. Native to South Africa, this winter bloomer is much less common than G. jasminoides, because it is less cold hardy and not as showy. Sometimes grown as an ornamental in south Florida. Primary use is as a rootstock to impart nematode resistance and increased vigor to G. jasminoides. Reaches 15 ft. tall and wide. Dark green leaves to 6 in. long; single, 3- to 4-in., white- to cream-colored flowers with a long tube and typically eight overlapping, petal-like lobes.
Provide fast-draining but moisture- retentive, acidic soil containing lots of organic matter. Plant gardenias high (like azaleas and rhododendrons) and don't let them be crowded by other plants or competing roots. To suppress weeds, mulch plants instead of cultivating around them. Feed every 3 to 4 weeks during the growing season with acid fertilizer, fish emulsion, or blood meal. Prune to remove straggly branches and faded flowers. Control whiteflies, aphids, and other sucking insects with light horticultural oil. Mag- nesium deficiency can result in yellow leaves with green veins; treat by dissolving one tablespoon of Epsom salt in a gallon of water and soaking the root zone (best done in early spring). Though you can grow gardenia as a houseplant, doing so can be pure torture: Mealybugs, mites, and whiteflies love it.