What is a Gardenia?
A gardenia, which is also known by the names Cape Jasmine, Gardenia jasminoides or Common Gardenia, is a flowering, evergreen shrub.
Even though they are one of the harder flowering plants to grow, that doesn't stop people from trying over and over again for success, as the compelling fragrance and beautiful white flowers are too tempting to not make the attempt.
The majority of gardenias will grow from a height of two feet to as high as eight feet, depending on the variety of the shrub. Outdoors, they can grow just as wide as they will high.
Also, depending on the type of gardenia, the flowers can be double or single, with the double, in my opinion, being a much better choice as far as how full and beautiful they look; yet they all look really nice.
Some of the gardenia specimens can have flowers with a diameter of 4 inches, which when they are doubles, are stunning.
Growing Gardenias Outdoors
The successful growing of outdoor gardenias is highly dependent on the soil type, location and amount of sun.
While this can be said of all flowers and shrubs, with the gardenia being extra sensitive, the conditions must be met in a more exacting way if you want to be successful in growing them.
Also check your zone to see if they can be grown outdoors without the cold weather ultimately damaging them.
Best Soil for Gardenias
Gardenias will respond best to an acidic soil, which is moist and has good drainage. The pH range should be between 5.0 and 6.0 for the best results.
If you have trouble finding a low pH soil, find the best area which includes the most favorable elements, and then add some sulfur in it to lower the pH.
The best time to plant a gardenia outdoors is in the spring or fall. They do best in partial shade, although full sun may be okay, depending on where you live.
AS for other factors, they don't do well when having to compete with other root systems, or if they have their roots disturbed. Thus it's best to mulch them in some way if they need to retain moisture around them. Don't cultivate them or they will usually respond poorly.
How to Plant Gardenias
Once you find the right place to plant your gardenia, then you can get about your business of putting it in the ground.
When you dig your hole, only go as deep as the root ball is, and about twice or three times as wide. If the soil is poor there as for quality, add some compost before placing the plant in the ground. If the soil looks good, it's okay to just leave it alone.
Once you carefully place the plant in the hole, then fill it up to about halfway, and then water it well enough so the soil settles down nicely. After the water drains, then fill up the remaining part of the hole. At this point water again.
If you're planting more than one gardenia, space the plants at least three feet to six feet apart.
Gardenia Maintenance and Care
Before you do anything with a Gardenia, including buying one, know that this isn't the type of plant you can put in the ground and leave; they are high mainenance, and must be taken care of if you want them to thrive and be successful.
As they do well in acidic soil, they also respond well to an acidic plant food. Gardenias can be fertilized in the spring, such as the middle of March, and also in the latter part of June. The reason for the later fertilizing is to encourage and help the plant to produce more blooms.
As for your particular zone, adjust the months mentioned above accordingly.
After that they should be left alone because the plant will respond to the feedings by sending up young growth which can more easily be damaged or destroyed when or if weather drops below 15 degrees.
Even so, even if they are severely damaged down to the ground, many times they will regenerate. Not fertilizing them in the latter part of summer and the fall gives them a better chance of surviving and not being damaged so badly.
Gardenias respond positively to water, and must have a minimum of an inch a week. To keep the plant moist, apply a form of mulch to maintain it at good levels.
The mulch also helps the finicky plant by keeping the ground temperature more constant.
Monitor the weather and its provision of water to gauge whether or not you need to supplement the process.
Aesthetic Maintenance Tips
As far as how you want your gardenia to look, in the spring be sure to prune the shrub to give it the shape you want.
In the fall, after the plant has flowered, take time to deadhead the shrub to give it even better blooms.
Remember, not only do those flowers look fantastic, but with most gardenias include that awesome fragrance that is the main inspiration for those choosing the shrub.
To Mist or Not to Mist
With the gardenia responding well to higher humidity, some people believe it helps the plant to mist it.
Others, think it can be a damaging practice because it could encourage fungal issues like leaf spot.
It seems that most people agree that misting is worth the possible risk, but each person will have to either experiment, or decide whether it's worth the risk.
Why Gardenia Buds Drop
If you've ever attempted to grow gardenias, or have seen others attempt it, you know the ultimate frustration is the "bud drop," which of course will usually occur just before they're ready to bloom, resulting in frustration from the anticipation of the flowers and their fragrance unfolding before you. This is why meeting the optimal requirements for the plant is so important.
Being almost like a human being with a low immune system, all sorts of things can happen to cause the buds of the gardenia to start dropping.
Among those that we can manage are too little or too much water, not enough light, rising temperatures, major temperature swings like a cold front moving through and than a rapid rise in temperature right after, and low humidity.
These same things can cause gardenias planted indoors to drop their flowers. There you would also have to consider cold drafts on the flowers, which could come from plants being placed in the air flow from an air conditioner.
Also within the house, the moving of a gardenia from one part of the house to another part of the house could result in dropped flowers.
What's the solution? Once you have the gardenia in place, whether inside or outside, it's best not to interfere with it other than than making sure it has enough water, but not too much.
Although there are no guarantees, we can at least know whatever caused the buds to drop came from a source outside of our control.
Like many people, these temperamental plants do not like change, and if you give it to them, they do the equivalent of throwing a fit by dropping their buds.
Now if there is some bud drop, don't be overly concerned, as long as it's not the entire plant doing it. Some of this is just natural, as it is with many other flower types.
The ideal temperature for gardenias is from around 68-74 degrees F temperatures in the day hours, and 60 degrees F for the evenings.
That of course is why in the southern parts of the United States, and other regions, they are known as more of a spring and early summer plant.
Even so, those temperatures will work well, no matter what time of the year it is, in most parts of the world.
Growing Gardenias Indoors
Just like growing gardenias outdoors, they are also a rewarding, but high maintenance plant indoors. They simply can't be neglected, and that must be understood in order to be successful at it.
The key to being successful in growing gardenias indoors is to recreate the optimal conditions it thrives in as close as possible.
Most people aren't aware of this or what it means, so when they bring that gorgeous plant home from the greenhouse, not too much later they have a plant with no flowers on it.
All the needs of the plant mentioned for growing them outdoors applies indoors.
Again, there are some differences among those that have grown gardenias inside, specifically as it relates to whether or not to place them in direct sun or not.
Some recommend only having them in bright light but not direct sun. Others have been successful at having them in direct sun for a minimum of half a day.
It think the reason for the discrepancy is where people live and how hot the direct sun hitting plants in the home is. If it's too hot, there will of course be problems because of the temperamental nature of the plant.
Humidity for Indoor Gardenias
While most important environmental factors required by gardenias can be reproduced in the home, probably the biggest challenge is humidity.
This is especially the case, just like with enough light, in the winter season The need to heat the home will drive down the amount of humidity, making it difficult to retain the right levels.
Ways to combat this are to group your plants together on trays with wet pebbles, or to run a humidifier.
Misting is practiced by some, but other than limited temporary relief, it doesn't do a lot for the humidity requirements of gardenias, and could end up facilitating some fungal diseases, although that's not a surety by any means.
As for indoor temperatures most conducive to growing healthy gardenias, as long as it's in a close range of outdoor plants, they should be okay.
It think if you keep the day and night temperatures within ten degrees of one another, the plant should respond favorably.
So if you have the temperature of your house at about 68 F in the day, then keeping it at about 58 F at night, or as low as 52 F or so, should suffice. Gardenias tend to respond well to these cooler indoor temperatures.
Remember, for buds to form strongly and stay on a gardenia, they must have cool night temperatures, with the best being in the 50s. Some have said they've done okay in the low 60s, so you have to try to see what works best in your circumstances. Either way, warm night temperatures in the home are devastating to the budding process of gardenias.
Fertilizing Indoor Gardenias
Just like gardenias prefer an acidic soil outside, maintaining them indoors will have similar requirements as far as fertilizing the plants go.
In this case, using a fertilizer that boosts blooming plants that need an acidic base should do the job. A product you may use for azaleas should work well for gardenias, as would one that may be used for rhododendrons.
Miracid® is one brand that could be used in regard to the acidic needs of the plant.
The bottom line for the successful growing of gardenias is you must keep things moderate and within tighter parameters than most other plants.
Stray too far outside the guidelines and you won't be successful; the plant requirements simply won't allow for it.
Now this isn't to say it's too difficult or impossible, just that you're going to have to watch them closer and stay on top of the conditions gardenias need to thrive.
If you've ever enjoyed the beauty and fragrance of a gardenia, you know it's definitely worth the time and effort to raise this fantastic shrub; whether you do it indoors or outdoors.
Emma4 on October 07, 2018:
I live in Kauai, Hawaii zone 9. I was thinking of planting them in large pots on my front porch. Our door opens up on the sides so the fragrance will be carried into the house. Temps run from high 60s -low 70s in winter but during spring and summer in the 80s. Humidity is not a problem. Plants would have some morning sun only. Will this work?
RTalloni on March 07, 2012:
Gardenia indoors…I wonder if I dare. Thanks for the info!
Paula from The Midwest, USA on March 03, 2012:
Hello, I saw the photo first, and thought gardenia? I truly love gardenias, and the idea alone takes me way back to when I was a very young girl. We had gardenias growing near our home, and the fragrance is one that might be an all time favorite scent!
What gorgeous flowers, and what a great hub about growing them indoors or out. I am going to consider growing them inside, because I know I can't grow them here outside. If you cut a few, put then in a shallow dish of water, they spread their amazing fragrance wherever they are. Loved it! Voted up and interesting, awesome and beautiful.