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It is difficult to walk past a gardenia in bloom without leaning in to inhale the wonderful perfume of its blossoms. With their glossy green foliage and ultra-fragrant, creamy white blooms, it’s no wonder these evergreen shrubs are so popular among gardeners. But how much water do gardenias need to produce such magnetic flowers?
Gardenias are typically prolific bloomers during the summer months, and some varieties maintain their evergreen foliage even through an extended period of freezing temperatures. In contrast to their tolerance for a wide range of temperatures, Gardenias tend to be a bit sensitive regarding their watering needs.
Water is essential for photosynthesis, bringing in the hydrogen necessary to perform the process. So naturally, it’s a pretty important element in caring for almost every plant I can imagine. Some less than others, but important, nonetheless. Each plant has its specific hydration needs. So, what are the needs of a gardenia plant when it comes to water?
The Short Answer
Gardenias need at least one inch of water per week. If they are receiving this much water from rain, there is no need to use supplemental irrigation because they do not favor soggy roots. In times of drought, watering deeply, once per week should be just right.
The Long Answer
Gardenias are drought-tolerant plants that do best in slightly acidic soil with good drainage. The generally accepted guideline for watering gardenias is that they need at least one inch of rain per week.
However, the true amount of water that a gardenia needs will vary based on the age of the plant, the soil type, the season, and the climate in which the gardenia is planted.
Newly Planted Gardenias
A newly planted gardenia with no established roots will need more water than a mature one. The location or container will also determine how much and how often it should be watered and for how long.
Gardenia roots are sensitive to overwatering, so they need good drainage to have healthy roots and still absorb enough water to support their glossy foliage and stunningly fragrant flowers. When planting a new seedling, look for a spot that won’t leave your plant with wet feet. Likewise, a potted gardenia should be in a pot with proper drainage.
Check Soil pH
Another factor is the makeup and pH of the soil. It’s a great idea to test your soil pH, as many plants thrive in slightly acidic soil. Without the right acidity, nutrients will not break down into a form gardenias can utilize.
Amend With Compost
Amending the soil with compost, manure, peat moss, or other organic materials will help to lower the soil pH if needed. This also improves water retention and water infiltration. If the soil is very clay-heavy or densely compacted, mixing in some coarse sand around the root ball is wise to aid in proper drainage.
Water 2-3 Times Weekly
A properly planted Gardenia should be watered 2-3 times per week for the first 6 weeks. The soil should stay consistently moist during this time but never soggy. This extra watering will encourage your new Gardenia to send out roots and establish itself in its new environment.
Potted Gardenias
A potted gardenia has similar needs to one in the ground. For the first 6 weeks, ensure your new plant has consistently moist (but not soggy) soil. Most commercial potting soil has a slightly acidic pH and doesn’t need to be amended in terms of acidity. Mixing in some cactus potting mix, pumice, or coarse sand may be helpful to encourage better drainage.
Mature Gardenias
Once established, this flower will need about 1 inch of water per week. The water can come from rainwater or from a hose. In times of regular rainfall, there will typically be no reason to water an established gardenia.
Gardenias are considered relatively drought tolerant but won’t thrive in dry soil. In times of drought, watering deeply once per week should be enough.
The soil should be slightly moist to the touch. It can be difficult to make this determination from the surface level soil, so checking the soil about 2-3” down will give a more accurate picture of the moisture level around your Gardenia roots.
If you live in a particularly hot or dry climate or have very sandy soil, you may need to water more frequently to keep your plant happy and blooming. Sandy soil heats faster and gets hotter than loamy or clay-heavy soil. Adding 2-4” of mulch around the roots will provide respite from the sun and retain moisture during dry weather.
Humidity
Another factor in the watering needs of these plants is humidity. Gardenias are native to tropical and subtropical regions of Asia and Africa. These places have climates that are typically quite humid, so it stands to reason that their foliage would be most comfortable with a similar amount of moisture in the air.
Gardenias need about 50% humidity or higher. Dry air will not only cause bud to drop, but it may also inhibit the formation of flowers altogether. This can be difficult to alter if your plant is growing outdoors in a drier climate, so some extra watering will help in this case. Just don’t overdo it.
For indoor flowers, there are easy solutions to the issue of dry air. Often, indoor air is dry in the wintertime, particularly when the heat is running. Most houseplants, except for true succulents, need humidity similar to gardenias. There are several ways to increase the humidity around your indoor plants.
Moving plants into a bathroom is a great way to give them extra humidity. Bathrooms tend to be the most humid rooms in the house, so there is little need to do anything other than run the shower, as usual, to keep the moisture level up. A humidifier is another great way to ensure your plants get the necessary humidity.
If you’re not comfortable with running a humidifier all the time or, like me, you know there is a good chance you will forget to fill it, then a pebble tray might be a better solution. This tray of water beneath the pot will evaporate, adding humidity to the air just around the plant. Daily misting is also a viable option.
Overwatering
Root rot and other fungal diseases are the main concerns in overwatering a gardenia. Fungus seeks out moist places to grow, and plant roots are sensitive to fungal infection. A plant that constantly has “wet feet” runs a strong risk of root rot.
Root rot can be identified by examining the roots of the plant, but short of digging up your plants, it tends to be rather advanced by the time it shows on the foliage. Root rot will cause yellowing of the leaves, beginning with the oldest leaves first, leading to generalized leaf drop.
Root rot affects the plant by inhibiting the absorption and transfer of nutrients and causing general decay. Once it reaches the foliage, the roots will likely be severely damaged. This is why it is so important to properly water gardenia plants without drenching them.
Underwatering
In attempting to avoid overwatering, it can be easy to end up underwatering. The good news is an under-watered gardenia stands a much better chance of recovery than an over-watered one. The plant may look bad at the moment, but it’s not impossible to revive it.
A dry plant will have an overall look of being dehydrated. The flowers will die quickly (if produced at all), and the leaves will have a brown appearance, curl inward, and feel brittle to the touch.
If you’ve been underwatering to the point that the leaves are drying out, you may lose some of that foliage no matter what you do. However, resuming a more effective watering routine should get your plant back in business in a few weeks. You should see healthy new growth within a few weeks, so if this does not happen, there may be another issue, such as an insect infestation.
Final Thoughts
Gardenias are not the easiest shrubs to care for, as they can be rather particular about their environment. A good watering routine is a key element of care that fosters a thriving and blooming plant.
Water gardenias 2-3 times a week during establishment and then about 1″ per week once mature. By establishing a positive care routine, gardeners can depend on their gardenia to produce scores of sensationally fragrant flowers throughout the summer and into the fall.
