Gardenia jasminoides
Contents
- Top Tips
- Location, Water, Humidity & Fertilisation
- Dormancy Period & Annual Flowers
- Common Issues
- Origins, Temperature, Propagation, Repotting & Toxicity.
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Top Tips & Info
- Care Difficulty - Moderate to Hard
- Maintain evenly moist soil, allowing only the top quarter of the compost to dry in between waters. Reduce hydration slightly in the autumn and winter, but be sure to avoid total dehydration.
- A generous level of humidity is mandatory for Gardenia; never situate it within three metres of an operating heat source as the risk of dehydration is high.
- Bright light with the possibility of an hour of morning sunlight is best to prolong the specimen's lifespan.
- While in bloom, fertilise once every two weeks using either a 'Tomato', 'Streptocarpus' or 'Flowering Plant' feed. You can even use a 'Houseplant' labelled product if you wish, but it may stimulate more foliage growth, too. Reduce fertilisation down to monthly intervals during the autumn and winter, using a 'Houseplant' feed.
- Scroll down to 'Dormancy Care & Annual Flowers' to learn about achieving new blooms each springtime.
- Repot every three years using a 'Houseplant' labelled compost and the next sized pot during the summer, shortly after the flowering period.
- If you're new to houseplants or lack total confidence, we wouldn't recommend Gardenia due to their complex care requirements and awkward behaviours.
Location & Light - 🔸🔸🔸
We'd recommend placing your Gardenia in a location that offers around an hour of morning or evening sunlight. Not only will this help with the overall strength and reliability of its health, but it can also prolong the lifespan of the individual flower. Remember to keep the soil evenly moist, as exposure to the sunlight and higher temperatures will always increase the rates of drying soil. Introduce a pebble tray to keep the surrounding moisture reliable, which in turn will slow the process of dehydration.
In terms of the ideal room, we'd recommend placing yours within a north, north-east or north-west facing window, or around a metre away from a south-facing one. Never situate the specimen in a shaded area (like on a shelf), due to the risk of sudden flower loss and slowed growth.
Water - 🔸🔸
Gardenia aren't a fan of having dry feet - just a few days of continuous droughts will cause catastrophic damage for the rest of its active life. Once the top quarter of the soil has dried out, rehydrate the soil using lukewarm tap water that has been allowed to sit for around twenty-four hours. Not only will this help with increasing the temperature, but it'll also decrease the high counts of chloramine and fluoride in its water. Under-watering symptoms include rapid flower or leaf loss and dry, sunken leaves or browning leaf patches; these issues are usually due to either forgetfulness, too much sunlight or too much heat. Over-watering symptoms include rotting lower leaves, yellowing leaves, a loss of buds or flowers, and root rot. Allow the majority of the soil to dry out in between waters, preventing a pool of standing water from accumulating beneath the pot. It's improbable that you'll over-water a Gardenia due to their thirsty nature, but always be cautious of root rot if it stays in too saturated soil for extended periods.
Humidity - 🔸🔸
Create a humidity tray to provide a moist and stable environment for your plant. If the surrounding saturation is too low or the heat too high, its leaf-tips may start to brown over and curl, especially in direct sunlight. Gently hose the foliage down from time to time to hydrate the leaves and keep the dust levels down.
Do not mist the flowers as this will cause Botrytis Petal Blight that can spread quickly if not dealt with accordingly. Never situate this plant within three metres of an operating radiator as it will cook both the plant and the surrounding air moisture, leaving you with a miserable specimen.
Fertilisation - 🔸🔸
Use a fertiliser high in potassium to prolong its flowers during the festive period - an excellent example would be a Tomato Feed. Regular fertilisers, for instance, BabyBio or Miracle-Gro, will still do the job but will favour foliar growth instead. For the rest of the year, a 'Houseplant' labelled fertiliser can be used to supplement the plant, still at monthly intervals.
Dormancy Care & Annual Flowers
Provide a bright, and cool autumn and winter period around 14℃ (57℉) to reinforce its dormancy. Keep the roots pot-bound to add further stress onto the specimen, which in turn will significantly heighten the chance of flowering. Blooms will generally appear in the summer, during the active growth season. The following steps should be taken from early autumn until the end of winter.
Sunlight & Location
Be sure to provide a bright location with little to no direct sunlight. Although the winter rays won't necessarily hurt the plant, be careful not to fall in the trap of sun-scorch and severe dehydration. Avoid deep shade and the use of artificial lighting at night or locations that boast temperatures higher than 18℃ (64℉).
Hydration
Reduce waters so that at least half of the soil becomes dry. It's essential to keep them on the drier side to life, as they'll think that hard times are ahead and therefore will need to pass its genes on to the next generation.
Occasional Feeds
During the autumn and winter, fertilisation should be performed at monthly intervals with a 'houseplant' feed. While the flowers are in development or in bloom, use a Tomato fertiliser to provide fortnightly nourishment of potassium.
Reduce Everything
This is to remind you that everything needs to be reduced - especially the temperature.
Temperature
This is the most significant step; reduce the temperature down by around 5℃ compared to the summertime or place in a room that's between 14º - 17℃ (57º - 62℉). You'll be at a significant disadvantage if the ambient temperature is kept constant throughout the year, as Gardenia will only respond in locations that have daily fluctuations of around 7℃. Never exceed the minimum temperature as it may lead to plant death or yellowed foliage at a bare minimum. If these steps are followed successfully, you could see a show of blooms in the following summer - but remember, dealing with nature may not always provide the results you'd relish.
A developing bud that'll open in about ten days time, lasting up to two weeks. If yours has sudden dropped off without opening, scroll down to the following section to learn more!
Common Issues with Gardenia
Under-watering is the biggest issue when it comes to a Gardenia. Typical signs include wilting, sunken leaves, rapid flower or bud drop and stunted growth. Not only will you have to be mindful of persistent droughts, think about which plant parts to keep dry. Its foliage must also remain dry at all times to prevent the development of diseases and blights. Those situated in direct sunlight or within four metres of a radiator are more likely to suffer from under-watering related issues.
Curled leaves and dried brown edges are the result of too little water and over-exposure to the sun. Although Gardenia can naturally do well in partial sun, those that haven't acclimatised to the harsh rays will show signs of sun-scorch and environmental shock. Gradually increase the amount of light every few days, starting from an indirect location to a few hours of morning/evening sun over a few weeks. Prolonged exposure will significantly speed the process of dehydration, so consider transplantation into a bigger pot in the spring to wrap the roots around moister soil.
Spider Mites are small, near-transparent critters, that'll slowly extract the chlorophyll from of its leaves. Have a check under the leaves, most notably along the midrib, for small webs and gritty yellow bumps. Click here to read our article about the eradicating Spider Mites, along with some extra tips that you may not find elsewhere.
A further pest to look out for is Whitefly. Although these small airborne critters shouldn't produce too much damage, an infestation must be destroyed quickly to reduce the chance of them spreading. Click on the link above to learn more about addressing these issues.
As mentioned before, powdery mildew and grey mould (Botrytis) are major threats among heavy foliage plants due to the compact nature that aids the spread of the diseases. Watering above the foliage will allow excess moisture to sit in the cubbyholes of the stem, enticing harmful bacteria to thrive. Remove the affected areas and improve the growing conditions by situating the plant in a brighter location with the use of the bottom-up method of irrigation.
Never situate it within four metres of an operating heat source, for instance, a heater or fireplace. Due to the high temperature, the plant will soak up far more moisture than those situated in cooler locations, increasing the chance of droughts and browning leaf-edges.
Lower leaf loss is a common and significant issue among gardeners. This unfortunate phenomenon could be a product of several different problems, most notably being dark locations, water-related abuse or environmental shock. Introduce the plant to a more well-lit area with a splash of off-peak sunlight; if caught in time, the leaf loss should stop within a week. If you feel that your watering habits aren't up to scratch, familiarise yourself with our care tips provided at the top of this article. It's always best to under-water a Gardenia than over-do it, purely on its poor ability to endure continued sogginess. The final culprit could be down to a sudden relocation; if you've recently purchased the specimen, the chances are it is still acclimatising to the new environment. Although this shouldn't happen, a vastly different setting will cause sudden foliage loss and stunted growth. You'll have two options of either waiting it out or presenting a more Gardenia-friendly environment, mentioned in the 'Location & Light' section.
Persistent wilting foliage could be the sign of inconsistent watering, which arises from periods of excessively moist and then dry periods. Although this is a common issue among horticulturalists, this shouldn't happen. The apparent cause could be over-watering and if the soil has been rather heavy for an extended period, think about relocating it to a drier, brighter environment with an inspection for root rot. In some other cases, it may be to do with too little soil moisture, which has then been over-watered within a short period. If you'd like to speak to ukhouseplants regarding this issue, don't be afraid to book a 1-to-1 call with Joe Bagley to help guide you through the step-by-step process!
Sudden flower loss can be caused by an array of different issues, including a change in location, too little hydration, too hot or cold temperatures or droughts and pests. Whilst the plant is in bloom, keep the soil evenly moist, to hydrate the thirsty work of producing flowers. Locations that are outside of the recommended temperature bracket, or have drastic fluctuations must also be kept off the cards, as Gardenia can be very sensitive to ambient change. The final issue could be to do with pests. Although it's doubtful that an infestation will cause a sudden change in health, have a quick inspection for Whitefly, Aphids, Spider Mites & Mealybugs. For those that display signs of pest damage, click on the appropriate links or click here for more pests.
A lack of flowers is caused by an insufficient dormancy period, served in the winter months. Locations that offer near-similar temperatures all year round won't allow the plant to go dormant, resulting in poor spring growth. To achieve, situate in a location that dips to around 14°C (57°F) with fewer waters. Allow the majority of the compost to dry out and provide a humidity tray while the radiators are operating.
The typical size of a Gardenia sold in garden centres. Maturity can be reached within five year, with the overall height only being 0.5m.
Origins
Gardenia consists of 140 species with natural distributions across the world, most notably in Africa, Asia and many Pacific islands. The genus was described by Carl Linnaeus in the mid-eighteenth century, honouring Dr Alexander Garden, a Scottish naturist at the time. The most popular Gardenia, the G. jasminoides, was brought over to England in 1761 from Eastern Asia. John Ellis queried whether the species was a Jasmine, instead later naming the specific epithet in honour of the genus.
The Distribution of Gardenia jasminoides.
Temperature
8° - 22°C (46° - 72°F)
H1c (Hardiness Zone 11) - Can be grown outdoors between late spring and summer throughout most of the UK while nighttime temperatures are above 10℃ (50℉). If you decide to bring the plant outdoors, don't allow it to endure more than an hour of direct sunlight a day as it may result in sun-scorch. Regularly keep an eye out for pests, especially when re-introducing back indoors.
Gardenia thrive in cooler locations and will generally flower better if a good dormancy is served in the winter when the temperature dips below 15°C (59°F).
Spread
Up to 0.5m in height and width. The ultimate height will take between 4 - 6 years to achieve.
Pruning
Remove yellow or dying leaves, and plant debris to encourage better-growing conditions. While pruning, always use clean utensils or shears to reduce the chance of bacterial and fungal diseases. Never cut through yellowed tissue as this may cause further damage in the likes of diseases or bacterial infections. Remember to make clean incisions as too-damaged wounds may shock the plant, causing weakened growth and a decline in health.
Allow the flowers to fully elapse (usually in mid summer) before pruning the foliage back a third in time for their dormancy - this will promote vigorous new growth that'll house the future flowers.
Propagation
Via Seed or Stem Cuttings.
Stem & Eye Cuttings (Moderate to Hard) - This method of propagation is troublesome without the aid of bottom-heat and a controlled environment. Choose the healthiest, most established stems that are wooded, yet still juvenile enough to bend slightly, being just thicker than a phone charger wire. Each cutting should only have a few leaves leaf, above 8cm of semi-wooded stem. Situate the cutting's lower half into moist 'Houseplant' compost; 'Blackleg' can occur when the bottom wound becomes infected, resulting in propagation failure - typically caused by water-logging or deep damage. Maintain bright light and evenly moist soil with the avoidance of direct sunlight or cold draughts. Wrap the pot (& foliage) in a transparent bag or within a miniature greenhouse, and provide bottom heat of temperatures above 18°C (54°F). Remove the bag and place into individual 7cm pots once the second new leaf emerges. Follow the same care routines, as mentioned in the article's top half. This method will take up to five months, so patience and the correct environment are paramount for success!
Flowers
Gardenia will bloom within the months spring and summer, when grown correctly with a cool dormancy in the winter months. Each individual flower can last up to two weeks, with the overall show spanning six weeks. Supplement the plant using a fertiliser high in potassium to prolong its flowers - 'Streptocarpus' or 'Tomato' feeds are an excellent choice. The Gardenia jasminoides is highly renowned for its oriental aroma and striking similarities to the true Jasmine.
Repotting
Repot biannually in spring using a 'Houseplant' labelled potting mix and the next sized pot with adequate drainage. Gardenia are far better potbound for several years due to the heightened risk of root rot and repotting-issues (like transplant shock), so only repot if you feel it's wholly necessary - restricted root growth will also increase the chance of blooms, too.
Hydrate the plant 24hrs before the tinkering with the roots to prevent the risk of transplant shock. For those situated in a darker location, introduce an extra amount of perlite and grit into the deeper portion of the pot to downplay over-watering risks. Click on this link for a detailed step-by-step guide on transplantation, or via this link to learn about repotting with root rot.
Book a 1-to-1 video call with Joe Bagley if you'd like a personal guide to repotting your houseplant. This will include recommending the right branded-compost and pot size, followed by a live video call whilst you transplant the specimen for step-by-step guidance and answer any further questions!
Pests & Diseases
Keep an eye out for mealybugs, scale, spider mites, fungus gnats, whitefly, vine weevils & root mealybugs that'll locate themselves in the cubbyholes and undersides of the leaves, with the exception of the latter two in the soil. Common diseases associated with Gardenia are root rot, leaf-spot disease, Botrytis, rust, powdery mildew & southern blight - click here to learn more about these issues.
Toxicity
This plant is classified as poisonous, so if small sections are eaten, vomiting, nausea, and a loss of appetite may occur. Consumption of large quantities must be dealt with quickly; acquire medical assistance for further information.
Retail Locations
Some florists & Online Stores. Specimens are likely to be found in spring or summer at most garden centres. A small selection of Gardenia are sold during the festive period, but generally won't last as long as those sold earlier in the year. It's not advised to bring outdoor specimens inside as this could lead to environmental shock or the introduction of foreign pests into the home.
Book a 1-to-1 Call with Joe Bagley
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