Last Updated on September 17, 2022 by Plant Mom Care
Gardenia is a flowering plant genus indigenous to the warmer climate zones of Africa, Asia, Oceania, and Australia. They are evergreen shrubs and can grow into small trees between 4–50 feet tall. Their glossy dark green and broad leaves are 2–20 inches long and 1–10 inches wide.
The remarkable and strongly scented flowers are white, or light yellow, either solitary or growing in clusters, with 5–12 petals and with a breadth of about 2-5 inches. Flowering occurs from spring to summer, they are usually grown as indoor plants due to their beautiful flowers.
Without the attraction of their wonderful scent, very few gardeners would attempt to cultivate these high-maintenance plants, which are also prone to many pests and diseases. They are usually cultivated in greenhouses. Nonetheless, a few months living with a flowering gardenia indoors makes these plants a worthy addition to your indoor garden.
Under suitable climates, they can be planted outdoors in spring or fall, usually using mature potted plants that will immediately produce flowers. Growing them from seeds usually takes 2-3 years for them to become mature enough to begin flowering.
Gardenias Light Requirements
Although these plants prefer full sun, some shade is necessary during the summer or the leaves might become scorched and buds might start falling off with too much sunlight. In warm climates, they grow best under full sun in the morning and shade in the afternoon.
In cool climates, they can be cultivated outdoors under full sun, particularly if the roots are protected by organic mulch. Plants growing in pots indoors need direct sunlight for 6-8 hours near a sunlit window.
These plants need watering twice a week or more during summer, with the soil kept damp but well-drained. Over-watering or under-watering the plant could stop the flower buds from opening and even start dropping off.
Apply 1-2 inches of mulch, preferably organic, to keep the soil damp and to maintain consistent soil temperature. The soil should be rinsed using distilled or rainwater to rid the soil of excess fertilizer salts every month.
This plant needs high humidity levels to thrive, extra moisture can be provided with regular misting and/or using a humidifier. More humidity is also necessary to prevent spider mites that tend to attack the plant under arid conditions.
This grows best in temperatures during the day of 65-70°F and temperatures of 60-65°F at night. Flower buds will not form if these temperatures are not maintained.
This plant needs rich, well-drained soil or a peat-based mix for container plants. Acidic soil is preferable, with pH levels around 5.0 and 6.0. Don’t plant it near concrete walls as the pH level might be too high for optimal growth.
Soil rich in nutrients from organic matter such as peat or compost will help enhance the growth of the plant.
Repot the plant once in 2-3 years when spring begins to give it room to grow, as its development will be stunted if it gets root-bound. Choose a nice big pot with ample drainage holes and fill it in part with appropriate soil.
Turn the container over while grasping the plant trunk and pull gently to extract the plant. Insert the plant gently into its new container and add more soil to fill the space. Water it thoroughly when done.
Gardenias can be propagated in spring from 3-4 inch stem cuttings taken just under a leaf node. Keep two leaves at the top, remove the rest and place it into the appropriate soil mix and keep it damp.
Placing the cutting near a bright window with plenty of light in the mornings and shaded during the afternoons will give the cutting ideal conditions to take root. New roots will begin setting after a month or so – transplant them into a pot filled with the preferred soil mix.
Fertilize the plant every 2-4 weeks during March-October with a diluted fertilizer meant for Gardenias. Do not feed it from November-February.
Prune the plant by removing faded flowers and older growth after the flowering season is done and growth becomes dormant. This will help the plant develop new compact growth and branching.
This should happen before the plant starts to form new buds as if you prune the plant too late, you will also remove these buds for the next season. Be particularly careful here – some varieties tend to bloom twice in a year so check what variety of plant you are growing before beginning the pruning process.
Gardenias Common Problems
If you notice the flower buds dropping off before they open, this might be caused by either low humidity, over-or under-watering, poor drainage, insufficient light, or over-or under-fertilization.
This plant needs high humidity to properly thrive, extra humidity can be provided with frequent misting and/or using a humidifier – this will also help keep spider mites from attacking the plant. Keep the soil constantly damp but do not over-water and ensure the soil/pot drains well.
The plant needs sufficient sunlight during the mornings and has plenty of shade from the hot sun in the afternoons. Feed the plant as recommended and give the roots a good rinse with distilled water every month to remove excess salts.
Low humidity or wet leaves or poor drainage can all make the leaves become brown or develop brown spots. Follow the recommended humidity levels, avoid getting the leaves or flowers wet when watering the plant and inspect the soil/pot for proper drainage.
Powdery mildew, sooty mold, and leaf spot can also make the leaves become brown and wilt. Check the plant frequently for aphids, scale, spider mites, whiteflies, or mealybugs.
Spray the foliage with insecticidal soap and neem oil to control/eliminate these pests and diseases. Check underneath the leaves and the stems for pests. Spraying the plant with an antifungal agent (horticultural oil mixed with baking soda and insecticidal soap) can help reduce the incidence of infection/infestation.