Gardenia
( gar - DEEN - ee - uh )
At-A-Glance InformationThis group of evergreen shrubs can take full sun or partial shade, and need regular to ample water. Known for their strong, wonderful fragrance and beautiful shiny dark leaves. Gardenia shrubs are native to the tropical and subtropical areas of Africa, Asia, Madagascar, Australia and the Pacific Islands. These shrubs produce white flowers which come in many forms. Gardenia shrubs can be used as potted plants on patios or walkways or be planted in the ground in mixed beds.
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Gardenia Species and Varietals
The genus Gardenia is included in the Coffee family, Rubiaceae, and includes 128 species and over 200 varieties. The genus was named by Carl Linnaeus and John Ellis for Alexander Garden, a Scottish-American naturalist. Gardenia growing zones vary by species; see the descriptions below for more information. To find your zone, click here: Zone Map.
Gardenia jasminoides (Gardenia augusta)
Grows best in zones 7-9, 12-16, 18-24, H1 and H2. This species is native to China, Japan, and Taiwan. Bright green leaves and very fragrant double-white flowers make this a great specimen. Hardy to 20 degrees Fahrenheit, but needs summer heat to thrive and bloom well. Difficult to grow in adobe or alkaline soils. Great in containers and raised beds, and can be used as hedges or screens. Varieties are outlined below.
'Aimee' ('First Love')
Upright growth 4-6 feet tall and wide. Very large double blossoms with elegant spirals. Blooms spring to summer. |
'August Beauty'
Erect growth to 4-6 feet tall and 3-4 feet wide. Loosely double flowers show in early summer. |
'Belmont'
Vintage variety that grows to 5 feet tall and wide, with large leaves and rose-like blossoms; blooms late spring to early summer. |
'Chuck Hayes'
Grows in zones 6-9, 12-16, 18-24, H1 and H2. Hardy variety that is heat tolerant. 4 feet tall and wide. Double flowers bloom in summer, heavy fall rebloom. |
'Frostproof'
Gets to 5 feet tall and 4 feet wide. Profuse blooms spring through summer. Buds are undamaged by late frosts. |
'Kimura Sikazaki' ('Four Seasons')
Compact grower to 2-3 feet tall and wide. Long bloom season spring to fall. |
'Kleim's Hardy'
Grows best in zones 6-9, 12-16, 18-24, H1 and H2. Forms 2-3 foot high mound. Single, star blooms intensely fragrant, profuse bloom in early summer and then sporadically. Cold hardy. |
'Miami Supreme'
6 feet tall and wide, with large double flowers that bloom in spring. Periodic blooms in summer. |
'Mystery'
6-8 feet tall and wide. Formal blossoms (standard for corsages) show in midsummer to fall. Needs pruning to keep it neat. |
'Radicans' ('Prostrata')
Miniature gardenia, gets to 6-12 inches tall and 2-3 feet wide. Double flowers bloom in early summer. Can be used as groundcover or container plant. Has a variegated variety. |
'Summer Snow'
Grows in zones 4-9, 12-16, 18-24, H1 and H2. 4-5 feet tall and wide, with fragrant double blooms that pop up late spring through summer. Very cold hardy. |
'Veitchii' (Everblooming Gardenia)
To 4 feet tall and 6 feet wide. Pure white blossoms late spring to fall, and continues into warm winters. |
Caring for and pruning Gardenia shrubs
Gardenias are a bit tricky to grow, but once gardeners learn their likes and dislikes, they can become permanent members of the garden, providing both beautiful leaves and flowers as well as powerful fragrance in the garden. Grow Gardenia shrubs in full sun to light shade, providing afternoon shade in warm climates. They prefer moist, well-draining soil that is rich (amended with plenty of organic material) and has a pH of between 5.0 and 6.5 (acidic). Soil pH is important for these plants, as they are sensitive to soils that are not ideal for their growing needs. Apply a 2-4 inch layer of mulch around the base of your Gardenia shrub to increase soil moisture retention. These shrubs are sensitive to extremes in temperature, preferring daytime temperatures of between 65 to 70 degrees Fahrenheit and nighttime temperatures of between 60 and 65 degrees Fahrenheit. They prefer high humidity, and will thrive in these conditions.
Fertilize every 2-4 weeks during their active growing and blooming seasons (March through October) with a diluted fertilizer that is good for acid-loving plants. Hold off on fertilizing from November through February. These shrubs should be pruned for shaping purposes when the plant is dormant to promote a bushier habit.
Fertilize every 2-4 weeks during their active growing and blooming seasons (March through October) with a diluted fertilizer that is good for acid-loving plants. Hold off on fertilizing from November through February. These shrubs should be pruned for shaping purposes when the plant is dormant to promote a bushier habit.
Propagation
Gardenia can be propagated either by using cuttings or from seed. To ensure that your propagated plant will have the exact same qualities and characteristics as the parent plant, use the cutting method. If you would like to experiment and see what plant you can grow from seed, just keep in mind that it will not necessarily be the same as the parent plant. To propagate your shrubs, follow the instructions below:
Propagating Gardenia by Cutting
Propagating Gardenia by Seed
Propagating Gardenia by Cutting
- Gather your materials. You'll need a clean, sanitized, sharp pair of garden shears, rooting hormone, a pencil, and a 3-inch pot filled with well-draining compost or other organic material. If you don't have any potting medium on hand, you can make some. Just mix together equal parts (by volume) moss peat and horticultural-grade sand or grit sand.
- In spring or early summertime, choose the plant that you'd like to propagate. Ensure that this plant has had a good watering the night before, as this will improve the chances your cutting will take root. Cut one or more 3 to 4 inch portion(s) of the end of a non-blooming branch and strip the leaves off of the lower half. Make a hole in your planting medium by pushing your pencil into the soil. Dip the end of the stem in rooting hormone, and plant it in your pot. Fill in soil around the cutting to support it, but do not pack it down too much.
- Moisten with water, and ensure that the pot has good drainage. Your pot should be kept in warm, sunny conditions indoors (and not in direct sunlight). Water whenever your soil is dry under the top layer. After about four to six weeks have passed, your cutting should be rooted. When you notice new growth, you'll know you have roots.
- Keep your new plant in an area with bright light (though not direct sunlight) and temperatures between 55 and 70 degrees Fahrenheit. Ensure that the soil stays moist, but not wet, until the next spring, when you can transplant it to its new home. Ensure that the last frost of the year has occurred before doing this, as it can seriously damage your new shrub.
Propagating Gardenia by Seed
- Keep in mind that the plant you get from seed will not necessarily mimic all of the characteristics of the parent plant, and that your Gardenia grown from seed will take around 2-3 years to start producing blooms. To propagate by seed, you will need a razorblade, a fine mesh strainer, a paper towel, a pot or tray filled with well-draining compost or other organic material, a spray bottle and a fork. If you don't have any potting medium on hand, you can make some. Just mix together equal parts (by volume) moss peat and horticultural-grade sand or grit sand. You will also, after a few weeks, need individual 3-inch pots for each seedling that grows filled with potting medium.
- Harvest your seeds. You'll know the seed pods are ready to be harvested when they are about 1.5 inches in diameter and have turned a dark brown color. Remove the pods from the plant, and cut them open with a razorblade. Pick out the seeds from the pod with your finger. Rinse the seeds using a fine mesh strainer and lay them out on a paper towel to dry. Then, place the seeds in a paper bag and allow them to dry out in a cool, dark, dry place for about 20 days to a month.
- In early winter, water your prepared seed tray or pot filled with soil, and ensure that good drainage is occurring. Place your seeds in your prepared pot or seed tray about a quarter inch to a half-inch under the soil surface. Cover them with soil and water with your spray bottle. Place your tray of seeds in a warm area that receives bright, indirect light. A greenhouse is the most ideal climate, but a planting tray inside a window will do as well. Germination usually takes 4-6 weeks from sowing. Once you begin to see seedlings sprout and they are able to be handled, transplant them to their own individual 3-inch pots, filled with the same potting medium as described in Step 1. Loosen the seedlings from the potting medium by digging down with the tines of your fork about an inch and a half, gently working the seedling up until it is out. Then, replant the seedling in its individual pot.
- Keep the seedling's potting medium moist, but not wet, by spraying the soil with your spray bottle. Keep your new plant in an area with bright light (though not direct sunlight) and temperatures between 55 and 70 degrees Fahrenheit. Ensure that the soil stays moist, but not wet, until the next spring (after the danger of frost has passed), when you can transplant it to its new home.
Problems and Pests
Gardenia shrubs suffer from the following ailments:
- Whiteflies
- Mealybugs
- Aphids
Gallery
Videos
How to grow Gardenias in your garden.
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How to plant Gardenia.
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Getting the most out of your Gardenia shrubs.
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Everything you need to know about caring for Gardenias.
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Resources
The New Sunset Western Garden Book: The Ultimate Gardening Guide (2012) - Page 332, Gardenia
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