plant of the month
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Gardenia augusta (syn.
Cape jasmine, Common
Gardenia plants feature
glossy dark green leaves and intensely fragrant Camellia-like
waxy-petaled flowers that can grow as large as 3 inches in
diameter. Bloom size and shape (flat or dome-shaped) vary among
cultivars, which include dwarf and standard.
Bloom colors range from bright white to creamy white; they
change to pale yellow as they age.
Blooms can last from three
to eight days, but the plants can live up to 10 years, indoors,
with proper care. Unfortunately, many consumers have limited
success with these plants because they are so demanding.
plants are available year-round from national and regional
IN-STORE AND CONSUMER CARE
Bright, indirect light is
essential for plants displayed indoors, but protect them from
direct hot midday sunlight. Outdoors (summer only), keep these
plants in shady, sheltered areas.
Keep the soil moderately
and evenly moist—but not soggy. Water thoroughly when the soil
surface is dry to the touch, using lukewarm soft water. Over
watering can cause leaves to drop, and irregular and under
watering can cause buds to drop.
To bloom, these plants
require a consistent, narrow temperature range—62 F to 65 F at
night and 70 F to 72 F during the daytime. Flower buds may drop
or fail to form if daytime temperatures are higher than 75 F or
if nighttime temperatures are higher than 65 F or lower than 60
Gardenias love high relative
humidity (at least 70 percent), which is best provided with a
pebble tray or humidifier. Misting the air around the plants is
OK but must be done several times a day; misting leaves can
cause fungal growth.
Fresh, moist (humid) circulating air is a necessity, especially
during the winter. Hot, stale and/or dry air can cause fungal
Feed the plants every two to three weeks, from April/May through
September/October, with a Rhododendron (azalea) food or
nonalkaline (acidic) fertilizer.
SOIL Gardenias require
acidic (5.0 to 5.5 pH), moist, well-drained soil. A peat and
soil mix is ideal.
GROOMING Remove blooms as
they fade, and cut Gardenias back when they have finished
REPOTTING Repot plants
yearly, in late winter or early spring (March-May), until the
roots fill an 8-inch-diameter pot. After the root mass reaches
this size, repot plants every two years.
Gardenias are moderately sensitive to ethylene gas, so
make sure your plants are treated with an ethylene inhibitor at
the greenhouse or during transportation. Also, protect them from
sources of ethylene gas, including ripening fruit, automobile
exhaust and tobacco smoke.
PESTS AND DISEASES
Mealybugs, scale insects, spider mites and aphids are common
problems for Gardenias. An infestation can result in sooty mold
or webbing on leaves. These sucking insects excrete honeydew,
which supports the growth of the black fungus.
Causes include nighttime temperatures lower than 62 F, alkaline
soil, poorly drained soil, over watering, watering with too cold
and/or hard water.
BUD DROP, LEAF DROP
These problems are the result of too little light, over or under
watering, poorly drained soil, lack of humidity, too high or too
low temperatures, and drafts.
NO BUD PRODUCTION
Failure of flower buds to form is a result of too high
temperatures (day and/or night) as well as too low temperatures
ROOT ROT Causes include
over watering and/or poorly drained soil.
is a member of the Rubiaceae (madder) family.
Relatives include Bouvardia, Cinchona
(quinine), Coffea (coffee), Nertera (coral
bead plant) and Pentas.
WHAT’S IN A NAME
The genus Gardenia was named for Dr. Alexander Garden
(1730-1791), a Scottish physician and botanist who lived in
Charleston, S.C. The species epithet jasminoides means
“resembling jasmine,” referring to the flowers’ fragrance.
HOME SWEET HOME
Gardenias are native to southern China. It was once
thought, however, that these plants came from the Cape of
Good Hope, in South Africa. This, along with the flowers’
fragrance, gave rise to the common name, cape jasmine.
Buy plants that are loaded with well-formed buds and,
perhaps, one or two open blooms.
Check flower buds, stems
and leaves for signs of wilt, browning or yellowing
foliage, mold and rot.