GARDENIAS
GARDENIA
Gardenias are lush, fragrant, flowering shrubs and are one of the most iconic and sought after blooming plants, enjoyed indoors and out. They belong to the family Rubiaceae, which is the fourth largest flowering plant family (coffee plants are also members of this family!). There are over 200 hybrids and species of Gardenia, which are native to Asia, the Pacific Islands, Africa, and Australia. Gardenia jasminoides is the most widely cultivated species of Gardenia, and is often used in hybridization.
Outside, Gardenias are an evergreen plant above zone 7b. This means that in Utah they are annuals, and will not withstand freezing temperatures. Inside, gardenias are evergreen shrubs, maintaining their dark green foliage throughout the year. Many folks choose to put their gardenias outside in the warm months, then overwinter them indoors once temperatures at night begin dropping below 60° F.
WATER
Gardenias are native to subtropical climates, and enjoy moist, well-draining soil. They only want to dry out roughly 10-20% of the soil between waterings. This means that the plant can be watered when it feels dry on the top of the soil. Gardenias prefer filtered water (NOT distilled) when possible, to prevent mineral deposits that can result in browning leaf tips. Do not allow your gardenia to sit in standing water for extended periods, or the plant may develop bud drop or root rot issues. If the plant is in a saucer, wait for all of the water in the saucer to be used before watering again. You can usually tell a gardenia needs more water if the leaves slightly start to wilt, but make sure it is watered hastily if you notice the plant wilting. They do not like to wilt, and the leaves and buds can quickly brown and dry out if left too long.
If the plant is kept outside in warm weather, they typically need watered more frequently than they do indoors, so be sure to check it regularly.
LIGHT & TEMPERATURE
Gardenias need bright direct light to maintain their glossy foliage and beautiful blooms. Indoors they should be kept directly in a west or south facing window with 4-8 hours of direct sun per day. Without this amount of direct light, gardenias are likely to drop most of their foliage, and may even drop their buds before they are able to bloom. In the summertime you can keep your gardenia outside in full shade (direct sun at this elevation will burn the leaves). They love warm weather and tend to bloom more prolifically outdoors. Gardenias can remain outside as long as nighttime temperatures stay above 60° F.
FERTILIZER
Gardenias are heavy feeders, and need to be fertilized every two weeks in spring and summer in order to bloom. Alternating a blooming fertilizer and an acid fertilizer is a great way to ensure the health of your gardenia.
Used coffee grounds are another great way to lower soil pH (make more acidic) and provide extra nutrients.
SPECIAL NOTES
Your Gardenia can bloom consistently from June-October when kept in the right conditions. Gardenias love humidity and heat, if your plant is struggling to open blooms, try using a hot shower to create a steam room and leave your gardenia in the “steam room” (not directly in hot water) until the humidity dissipates. This can help the buds to open up more easily. Gardenias also enjoy humidifiers, which is the best way to raise humidity consistently indoors.
Gardenias should be pruned to shape in late summer/early fall in order to generate vibrant new growth in the spring.
Gardenias can be prone to some pests, regularly showering off the foliage and removing unhealthy stems can help to prevent or control pests on your fragrant shrub.