Gardenias are a sight to behold with their waxy, creamy-white blooms and leathery, dark green leaves that make this plant attractive both as a flowering plant and as a foliage plant.
But all that beauty comes with a price — gardenias are notoriously temperamental and difficult to grow, especially outside their subtropical and tropical native lands.
But don’t let this discourage you, especially if you don’t mind giving your gardenia plants some extra attention. I trust the plant care recommendations below will come handy in growing gardenias.
Size & Growth
The height which gardenias achieve at maturity, depends on the gardenia cultivar you’re growing.
Most cultivars will reach a height of 3 to 8 feet and about the same in spread. But there are also dwarf gardenia varieties that reach a height between 6 inches to 2 feet.
The plant has a shrub-like growth pattern, which explains the ornamental value these plants boast.
While dwarf varieties make excellent houseplants because of their manageable size, larger cultivars can also be kept indoors, where they tend to stay at an average size.
One of the first difficulties in successfully growing a gardenia plant is managing its light requirements.
Generally, gardenias are sun loving plants, which means they should receive full sun exposure. However, in very warm zones, gardenias fare better if they get full sun exposure during the first half of the day, then light shade during the warmest parts of the day.
Mulch around the base of the plant can help retain moisture and prevent dehydration due to full sun exposure.
If grown outside in containers, it’s best to avoid full sun exposure. A site with filtered shade or bright, indirect light should be chosen over direct sun exposure.
Indoors, however, the situation is different. You should place gardenias in a sunny window with 6-8 hours of direct light.
Another difficulty that arises with gardenias is related to correctly watering them. Most gardenia plant care guides will recommend that you keep the soil moist but not soggy.
There’s also the recommendation to give the plant 1 inch of water each week. So, if it doesn’t rain enough for gardenias grown in the garden, you’re going to need to water them.
Adding a layer of organic mulch (2-4 inches) will also help with moisture and temperature control during periods of warm weather.
To avoid overwatering or underwatering your gardenias, simply poke the soil with your finger to see its moisture level. Don’t allow the soil to dry out completely.
Gardenia plants have special requirements even when it comes to the soil, they grow in. For starters, the soil should be well-draining so it doesn’t become saturated with too much water that will make the mix soggy.
Secondly, gardenias need slightly acidic soil with a pH between 5.00 and 6.00. Use a pH meter to check the soil’s acidity. Keep it within this range. Soil that’s too acidic or too alkaline will not work for the gardenia.
As for the quality of the soil, it should be rich in nutrients with a high content of organic matter. The addition of peat moss or manure helps tremendously in keeping this plant happy.
Temperature & Humidity
The temperature range in which gardenias feel most comfortable is between 65-70 F during the day and 60-65 F during the night.
When grown outside, gardenias should be taken indoors during cold winters. Outdoors, it can be grown all-year round only in USDA hardiness zones 10 and 11.
As a high-humidity, gardenia plants need their humidity levels supplemented through a humidifier or a humidity tray when the air becomes dry.
Misting is also suggested by some guides, but given the gardenia is prone to fungal leaf spot, I’d recommend against misting this plant.
Fertilizing is important for gardenias, especially when fertilized correctly and with a formulation that works well for these plants.
Choose a fertilizer for acid-loving plants and make sure to dilute it correctly to prevent fertilizer burn issues.
Apply the fertilizer every two weeks from March to October, which is the growing season for these plants. Don’t fertilize from November through February as the plant enters a rest period that should not be disturbed.
Potting & Repotting
For gardenias grown in pots, you should consider repotting when the roots are growing out of the bottom of the pot.
Pick a pot that’s only 1 or 2 inches larger in diameter than the previous pot. Make sure it’s fitted with drainage holes.
Transfer the plant to a new pot only in early spring and not during the summer to prevent transplant related but blasts.
Use well-draining potting mix or create your own mix by using 2 parts peat moss, 1 part potting soil and 1 part sand or perlite for a mix that gardenias will thrive in.
How to Propagate Gardenia?
If you want to propagate gardenias, make sure you get stem cuttings with leaf nodes on them. Cut 3-4 inch long stem cutting just below a leaf node.
To enhance rooting activity, you can dab the cut ends of the stem cuttings in rooting hormone. This will facilitate root production and ensure a higher success rate.
Simply plant the stem cuttings in moist, well-draining potting mix and keep out of direct light, but do make sure they’re exposed to bright, indirect light.
Keep the potting mix moist and not soggy or too wet. Once the stem cuttings put down some roots, they can be transferred again to a final location or planted outdoors in the garden.
Known as quite the handful among plants when it comes to maintenance, gardenias are still a beloved shrub with a beauty that outshines that of many ornamental plants.
If you don’t mind the extra attention these plants crave or if you live in a zone in which they’ll otherwise thrive, go ahead and try your hand at growing these lovely plants.
And come spring and summer, when their creamy-white blooms come in, you’ll agree with me when I say that gardenias are well worth the effort.