Read our guide to Gardenias for everything you’ll ever need to know! Tips for planting & caring for “Cape Jasmine”
Gardenia is an important family of plants that contains about 140 species of magnificent flowering ornamentals. Although the genus offers so many species, only some of them are popular in the gardening world. Some of the most remarkable ones are G. brighamii, G. cornuta, G. elata, G. jasminoides, G. scrabella, G. thunbergia, and G. volkensii and they all deserve a place in your garden.
The plants from this genus go by their most common names “Gardenia” or “Cape Jasmine”. They originate from the tropical and subtropical regions of Africa, Madagascar, Asia, Australia, and the Pacific Islands.
Gardenia shrubs are beloved by gardeners worldwide thanks to their impressive size. They can be grown both indoors and outdoors and their blossoms smell absolutely mesmerizing. Some gardeners think that gardenias are fussy, and although they are not among the easiest plants to grow, caring for them will not be as difficult as you might expect.
Keep reading our guide to find out more about growing and caring for Gardenias!
About Gardenias
- Named after Dr Alexander Garden, these mesmerizing flowering shrubs were not actually discovered by him. The flowers got their name as a way to cherish and honour the impressive contributions that Dr Gardem made to the fields of botany and zoology during his lifetime.
- Thanks to its superb appearance and relatively low-demanding nature, the Gardenia jasminoides species has gained the prestigious Award of Garden Merit from the Royal Horticultural Society.
- Gardenia is the national flower of Pakistan. In Eastern Asia, Gardenia jasminoides has various common names depending on the area. Locals call it kuchinashi in Japan, chija in Korea, and zhīzi in China.
- The fruits of G. jasminoides play an important role in traditional Chinese medicine, used mostly for their calming, cooling, and clearing properties. People also use the fruits as a yellow dye for food and fabric colouring.
- In France, gardenia flowers are worn traditionally as boutonnières when men dress up for the evening. During the Gilded Age, only the members of the upper class wore Gardenias.
- Some say that the founder of psychoanalysis, Sigmund Freud, told to the poet Hilda Doolittle that Gardenias were his favourite flowers.
- Gardenia plants make excellent additions to several landscape decorations, such as specimen plantings, hedges, espaliers, and even containers. Likewise, they are lovely cut flowers for a vase in indoor settings.
- The beauty of gardenias has made them popular wedding plants. But purchasing them by the stem is not possible and they are also quite delicate, so these flowers tend to be quite expensive.
- Plant your Gardenias alongside classic companions like Torenia, Brunnera, Ferns, Hostas, Impatiens, Cast-iron Plant, Solomon’s Seal, Toad Lily, or Wax Begonia.
- Gardenias thrive in tropical and subtropical gardens and they require plenty of morning sun, shade in the afternoon, moist and well-drained soil that is acidic and nutrient-rich, high levels of humidity, and temperatures around 18-21°C.
- Gardenias can be grown outdoors in USDA plant hardiness zones 10 and 11. In other regions, you can grow gardenias in containers and bring them indoors during the cold months.
- Cape jasmines are mildly toxic to pets, so you might want to keep them in a spot where your curious furry friends cannot reach them.
Gardenia Features: An Overview
- Gardenia plants belong to the coffee family, Rubiaceae. They are evergreen shrubs and small trees that can grow from 3.3 to 49.2 feet (1-15 m) in height. These popular shrubs grow can grow as tall as 6 feet (1.8 m), but their sizes depend on the variety.
- Their foliage consists of many thick, lustrous, lance-shaped, glossy to leathery, and dark green leaves that usually grow oppositely arranged or in whorls of three to four. The leaves can measure up to 19.7 inches (50 cm) in length.
- Gardenia plants are seasonal bloomers. In warm climates, they can produce flowers throughout the year. In cooler climates, these plants generally bloom from late spring to early summer.
- Their blossoms show up solitary or in small clusters. They have a tubular-based corolla that features 5 to 12 petals. The flowers measure between 2 to 4.7 inches (5-12 cm) in diameter.
- Gardenia flowers have an amazing, strong perfume. They come in various shades of white, cream, yellow, and golden.
- Gardenia plants, especially G. jasminoides, are very generous when it comes to the number of varieties that you can choose from. These varieties will surprise you with different flower sizes, shapes, and growth requirements.
- The most attractive Gardenia cultivars include ‘Aimee’ (large white blooms), ‘August Beauty’ (profuse flowers), ‘Buttons’ (intense fragrance), ‘Celestial Star’ (cold-hardy), ‘Chuck Hayes’ (bushy growth habit), ‘Coconut Magic’ (huge flowers), ‘Daisy’ (cold hardy and heat-tolerant), ‘Four Seasons’ (long blooming season), ‘Heaven Scent’ (hardy and very fragrant), ‘Mystery’ (large blooms), ‘Pinwheel’ (unique flower shape), or ‘Radicans’ (compact size).
- As you might have noticed, all the cultivars mentioned above are white. So it is safe to say that the most popular colour for gardenias is white, but these attractive flowers can also be yellow (Gardenia ‘Aurea’ and Gardenia ‘Golden Magic’). Kopsia fruticosa is sometimes referred to as pink gardenia, but it belongs to a different plant family.
Growing Gardenias
The amount of lighting Gardenia plants need will typically vary depending on the setting in which you want to grow them. In indoor settings, potted Gardenia plants will benefit from bright light, but not direct exposure, especially during the summer months. They will do best near a sunny window that can provide them with some afternoon shade. In outdoor settings, place your Gardenias in a partially shaded location.
Temperature-wise, Gardenia plants are cold-hardy in the USDA zones 8 to 11. In general, Gardenias thrive in day temperatures between 65 and 70 °F (18-21 °C) and values of 60 to 65 °F (15-18 °C) at night. Make sure you avoid growing these plants in places where they might be affected by cold drafts.
Even if Gardenia plants should not be exposed to frosty conditions in their area of hardiness, it is always a good idea to prepare your buddies for any surprises. To do so, add a generous layer of mulch at the base of your plants to insulate their roots. Moreover, you can purchase a frost cloth to protect your plants during nighttime. In doing so, you ensure that your gardenias can survive lower temperatures.
Planting Gardenias
The ideal location for established gardenias is in a place where they’ll get at least 6 hours of sunlight each day. If you live in a very warm climate where summer temperatures are very high, it would be best for your gardenias to get shade in the afternoon. Patios and decks are great locations for gardenias, as they will get the protection that they need and you’ll get to enjoy their fragrant blooms.
As tempting as it might seem, it is not recommended to grow your gardenias right in front of your house. Why? Because even though the flowers are beautiful and they smell great, they don’t bloom at the same time. So, a gardenia bush might look half dead, and that isn’t always the most attractive view. Picking the spent flowers regularly might be a solution, but not if your bushes become very large, or if you don’t have a lot of time on your hands.
When it comes to their growing medium, Gardenias are that type of plant that enjoys growing in acidic substrates with a pH between 5.0 and 6.5. The soil must also come with excellent drainage and be rich in nutrients and organic matter. You can find this type of soil commercially as traditional potting mixes that have a peat base.
- Elegant Appearance: White Gardenia flowers are known for their pristine, snow-white petals, which add a touch of elegance and sophistication to any garden.
- Fragrant Blossoms: These flowers are highly prized for their intense, sweet fragrance, which can fill a garden or home with a delightful scent.
- Evergreen Shrub: Gardenia plants are evergreen, providing year-round foliage and ensuring your garden remains lush and green even when the flowers are not in bloom.
- Attractive Foliage: The plants feature glossy, dark green leaves that offer a beautiful contrast to the white blossoms, enhancing the overall visual appeal.
- Versatile Growing Conditions: White Gardenia flowers thrive in well-drained, acidic soil and prefer partial shade to full sun, making them adaptable to a variety of garden settings and climates.
- Hardiness zone.8-11
- Grow.Plant the seeds in a pot with a mixture of potting soil, peat moss, and perlite in the early winter. Place the pot out of direct sunlight and keep the soil moist. Germination should occur in four to six weeks.
- Tall.5-6 ft. tall, 5-6 ft. wide.
- Sun.Indoor potted gardenias prefer bright light but not direct sunlight, especially during summer. Placing them in a sunny window that gets afternoon shade is best.
- Self-seeding.Grow from seed and enjoy growing with your family.
- STUNNING CAPE JASMINE: Outside, gardenia is best grown in a pot so it can be moved under cover in winter to protect from frosts or winds. In areas with favourable conditions year-round, plant gardenia in a raised bed or in the ground.
- EASY TO GROW: Soak the seeds in water for 24 hours then plant. Wait till the last frost has passed or start indoors till temps are optimal.
- GROW TIPS: Plant 1/4 inch deep and 2-4 seeds in each hole. Water when planting and as needed. Keep the seedbed free of weeds and grasses to optimize growth. A little mid season nitorgen will really boost the yield.
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Gardenia plants that grow in the garden are not heavy feeders, so they will need fertilizers only twice every year. Feed outdoor Gardenias with an acid-rich fertilizer once in mid-March and once again in late June. Keep in mind that you should always follow the instructions on the package. Plus, you should either dilute the fertilizer with water or mix it directly into the soil. Potted Gardenias, on the other hand, will perform well when you fertilize them every two to four weeks. Feed your Gardenia plants with a fertilizer designed for acid-loving plants diluted at ½ strength from March to October.
If you want to grow your Gardenias in pots, you will have to repot them to ensure that they continue to be healthy and happy. The best time to transplant your Gardenia plants into larger containers is usually in spring. It is best to move gardenias in a slightly larger container when they seem root-bound or look less vibrant than usual.
Once their blooming period has ended, you can prune your beloved Gardenias. During this process, remove all the unhealthy branches and spent flowers. It is best to use sharp garden shears to shape back the green and brown wood.
Watering Gardenias
Your Gardenia plants will be grateful if you provide them with one inch (2.5 cm) of water once every week. When watering these beauties, avoid touching their leaves with water because this can result in fungal leaf spots. The frequency of watering should change during the winter – spoil your plants with a drink less often, only to maintain the soil slightly moist to the touch. The flowers can also be quite sensitive to water and can turn coffee brown.
In terms of humidity, you should maintain a high humidity level around your Gardenias, somewhere above 60 per cent. If the air around them is too dry, you can mist them regularly or use a humidifier to maintain the ideal levels of humidity. We recommend you test the soil’s pH and amend it with a teaspoon of agricultural sulfur in case it does not suit the demands.
Propagating Gardenia
The most convenient way to propagate your Gardenia plants is through stem cuttings. Many gardeners prefer to use those cuttings taken during the pruning routine. These cuttings usually have enough time to develop a healthy root system and grow nicely before winter dormancy. Are you ready to start propagating your gardenias through stem cuttings? Keep reading!
Stem Cuttings
The first step is looking for healthy, green stems and cutting about 3 to 5 inches (7.5-12 cm) off them using garden shears. Next, remove all the leaves, but make sure you leave the top set of two alone from each cutting. After this step, dip the cut ends of the stems in a rooting hormone for great results.
Fill small pots with moist potting soil and plant each cutting in its individual one. Cover each container with a plastic bag, then pop them with garden stakes. Place the pots in a warm room with bright, indirect light and keep the substrates moist until the roots develop well. This might take about four to eight weeks. Once this period passes, if you want to, you can transplant the tiny Gardenia plants in the garden.
You can also root gardenia cuttings in water. All you have to do is to place the freshly cut stems in a bottle or a vase and submerge it in water by 3-5 cm (1-2 inches). Place the bottle on a windowsill that gets plenty of sun in the morning. Your cuttings should be protected from midday or afternoon sun because the water might overheat and that might prevent you from getting the best results. Refill or change the water as needed during the rooting process, which should take about one month. Once the stems have developed roots, keep them in water for another month or so. Once the roots seem strong, you can plant your new gardenias in the desired location.
Seeds
Although the easiest and fastest way to propagate gardenias is through cuttings, you can also try your hand at growing these beautiful plants from seeds. It is important to mention that gardenias grown from seed might take one or two years to start blooming. Also, hybrid gardenias don’t always produce seeds, so don’t be surprised if the gardenias that you are already growing aren’t very generous in this department.
If your established gardenia plants produce seed pods, harvest them, open them up, and collect the seeds. Put the seeds in a colander or other similar container and rinse them with cold water. Place on a paper towel until dry, then keep the seeds in paper bags until you decide to start them. You can start the seeds right after their collection, or at a different time (perennial seeds are usually viable for 2-4 years). It is important to mention that not all seeds will be viable, so it’s important to start more, just to be sure.
Before placing the gardenia seeds in the soil, let them soak in water for 24 hours. Sow them 0.5 cm deep (1/4 inch) in a mixture of peat moss and perlite or sand and keep them at room temperature (ideally around 23°C/75°F). The germination process can take between 3 weeks and 4 months, so you will need plenty of patience as gardenia germination can be quite erratic. Once you have your seedlings, you can transplant them into individual containers, in well-draining, peat-based and nutrient-rich potting soil. To make your own potting soil, mix equal parts of perlite and peat moss and remove the clumps, debris, and pebbles. Unless you live in very warm climates, keep your gardenias in containers that you can move indoors during the cold season. If, however, you live in a tropical climate and wish to grow your gardenias outdoors, you can transplant the seedlings into the garden once they have at least three pairs of leaves.
Gardenia Pests and Diseases
Gardenia plants may encounter some issues regarding pests, so it is best to keep an eye out for aphids, scale, mealybugs, spider mites, and whiteflies. If you notice any of these nasty intruders on your plants, you must take action. Luckily, you can control their spread very easily. All you have to do is wash off the pests as much as you can and apply horticultural oil or soap on the infected parts daily until you no longer can see the pests. Make sure you always check the underside of the leaves, because that’s where most of these pests like to hide.
Because Gardenias thrive in places with high levels of humidity, fungal diseases are also common problems while growing and caring for them. Some of the most common problems are leaf spot, powdery mildew, sooty mould, dieback, and anthracnose. You can treat some of these diseases with suitable fungicides. In other situations, however, you will have to remove and destroy the infected specimens. It is important to remember that when it comes to pests and diseases, prevention is key. Avoiding these issues is sometimes easier than treating them, so make sure you avoid overwatering and overcrowding and keep your garden tidy.
Bud drop is another common issue that some gardeners might face when growing gardenias. The main causes of bud drop are different environmental stressors such as overfertilization, overwatering, underwatering, bad soil drainage, cool weather, too little light, rapid changes in temperature, and extreme weather. This issue can also be caused by pests such as aphids and nematodes.
Like most plants, gardenias can develop yellowing leaves and this isn’t always a cause for concern. Like all evergreen shrubs, gardenias will go through a natural cycle and at some point, the older leaves will turn yellow and drop. However, yellowing leaves can also indicate an infection, an infestation, or environmental problems.
Gardenias that don’t get enough iron can develop iron chlorosis. This problem manifests through pale leaves. In this situation, it’s best to test the pH in the soil and amend it as needed.
You can find more information on gardenia pests, diseases, and other common problems here.
In Conclusion
Yes, Gardenia plants might be a bit fussy when it comes to their environmental and growing preferences. But if you grow them in environments that mimic their natural habitats, you shouldn’t encounter any problems. When the surrounding environment is proper, you can basically let them take care of themselves. Overall, Gardenias are great companions to have around if you pay attention to their basic needs. And what can be more rewarding than a thriving Gardenia that enchants us with its bewitching perfume? If you don’t live in a tropical or subtropical climate, you can still enjoy these beautiful ornamentals by growing them in containers.
Are you growing gardenias? Let us know in the comments section!
