There are two camps of flower enthusiasts:
- those who prefer low-maintenance plants
- those who will go the extra mile for high maintenance plants
For the latter group, Gardenia jasminoides (gar-DEEN-ya jaz-min-OY-deez) is well worth the effort.
Sometimes referred to as common gardenia or cape jasmine, this species of gardenia is native to Southeastern Asia. It ranges from Southern China and Japan to India and Bangladesh.
As a perennial member of the Rubiaceae family, it not only has over 140 relatives in the Gardenia genus but several gardenia jasminoides cultivars of its own, including:
- Chuck Hayes
- Crown Jewel
- Golden Magic
- Shooting Star
- Summer Snow
- White Gem
Each of these cultivars was bred for various traits, such as size, cold tolerance, bloom time, and color.
Gardenia jasminoides Care
Size & Growth
This evergreen shrub tends to grow to around 3′ – 8′ feet, with indoor plants averaging a mere 18″ inches.
Dwarf varieties of Gardenia jasminoides range a much smaller 6″ inches to 2′ feet.
Common gardenia has a medium growth rate, although some cultivars will grow more slowly.
Flowering & Fragrance
Cape jasmine is well-known for its unique fragrance and creamy white blooms.
These blooms first appear in mid-spring and last into summer.
Thanks to the many cultivars, you can choose a version of gardenia with larger or smaller flowers, either single or clustered.
Some cultivars also offer shades of white or pale yellow and may bloom earlier or later in the growing season.
Learn about the bloom time of Gardenias here.
Light & Temperature
Common gardenia burns easily by direct sunlight and is best suited for bright, indirect light.
The plant will somewhat tolerate partial shade conditions, especially in the afternoon.
In general, only plant cape jasmine outdoors in USDA hardiness zones 8 to 11, although some newer cultivars will survive down to zone 7a.
Its ideal temperature range is between 68° – 74° degrees Fahrenheit. Older varieties are not frost tolerant, so the minimum night temperature should not fall below 60° degrees Fahrenheit.
Gardenias need a high level of humidity to thrive, so if you’re not keeping it in a terrarium, you’ll need to improve the ambient humidity levels.
Set up a humidifier near the plant or place a tray of pebbles under the pot and fill it with water.
Low humidity will not only dehydrate the plant but will also cause blooms to dry out and fall off early.
Watering & Feeding
Common gardenia requires some careful watering.
As long as the soil or potting mix is well-drained, it will be tougher to overwater it.
Check the soil regularly to ensure the soil is moist.
Once the soil has dried down about 1″ inch, water it thoroughly.
Avoid getting water on the blooms, as this can cause the flowers to turn brown.
Fertilize your gardenia after the final frost using a good Azalea or Gardenia fertilizer (2-1-1 NPK ratio) as directed on the packaging.
Feed again six weeks later to ensure fuller blooms.
Soil & Transplanting
Proper soil is essential to a healthy gardenia. Buy a commercial gardenia potting mix or create your own.
Any homemade mix should be peat-based and have excellent drainage, with a pH between 5.0 and 6.0.
Amend the soil with organic material and cover with a mulch layer to help protect the roots from temperature changes and keep moisture in.
The mulch will also help control weeds, which tend to cause gardenias a lot of grief.
When possible, avoid transplanting your gardenia, as it stresses easily and reacts to any degree of root damage.
Grooming & Maintenance
The best time for pruning your gardenia is after it stops blooming.
At this point, you should remove any straggly limbs.
Deadheading (removal of spent blooms) is also advised.
While optional for many plants, pruning your gardenia before it goes into hibernation will often improve its frost resistance and bring it back stronger the following spring.
How To Propagate Common Gardenia
As with many popular ornamentals, propagate cape jasmine through stem cuttings.
Harvest the cuttings in early spring, removing 3″ – 4″ inches from the tip of a stem to just below a leaf node.
Dip the cutting into rooting hormone at the cut end.
Plant the cuttings into pots containing a mix of gardenia potting soil and perlite. Keep moist.
Once the roots have formed, transfer into 3″ inch pots.
Experienced gardenia enthusiasts can also propagate via seeds.
Harvest the seeds from pods dried over 4 weeks and plant ⅛” inch deep in a perlite and peat moss mix.
Place the planter away from sunlight and keep the soil moist until sprouts appear between 4 and 6 months later.
Transplant the seedlings into pots with a peat-based potting mix once they’re several inches high.
Cape Jasmine Pests Or Diseases
Poor maintenance and care can lead to many problems for common gardenia.
The most dangerous issue is root rot, caused by overwatering.
Other common problems include bud drop, powdery mildew, and stem canker.
Gardenia is susceptible to fungal infections. Phomopsis gardeniae, a species that mainly targets gardenia varieties, causes stem cankers.
Common infestations include all the usual suspects:
- Spider Mites
Gardenias are mildly toxic to pets and may cause diarrhea, hives, and vomiting. They are non-toxic to humans.