9 Care Tips for Potted Gardenias in Winter

Gardenias are wonderful tropical plants that originate in parts of Asia, Africa, and Australia. They’re relatives of the coffee plant and produce some of the best-smelling flowers I can think of. In warm climates, they are evergreen and fairly cold-tolerant. 

If you live in a climate where significant bouts of temperatures below 15°F (-9°C) occur, you’ll need to keep this shrub in a container. They are easy to care for, and they make good houseplants if you can provide the right conditions. 

Like many plants, gardenias have needs that shift in winter as they go semi-dormant. While their needs decrease somewhat, you can’t leave them to fend for themselves during this time. Remember that they are evergreen and never go completely dormant. Here are some tips on keeping your gardenia looking its best through the winter and beyond!

Bring It Indoors

This tip applies mainly to those who garden in Zones 8 and below. In Zones 9-11, your shrubs can remain outdoors through the winter, though I would bring them in for any prolonged hard freeze. In Zones 7-11, you can plant these outdoors, but containers hold less soil, so plants in pots are more vulnerable to cold. 

Unless you’re growing a cold-hardy selection, bringing your gardenia indoors is an absolute must in any climate north of Zone 8. If you leave it outside accidentally during a cold spell, try not to panic. You may see some leaves turn yellow and drop over the next few months, but their roots are surprisingly resilient. 

Keep It Cool

When it comes to temperature, there is a balance to caring for potted gardenias that are living indoors for the winter. Even in tropical climates, these shrubs get a period of cool weather in the winter. It doesn’t have to be freezing to help, but it’s important to place your plant in a space where the temperature cools at night.

This can be tricky because it still needs sun to keep those leaves green. However, nighttime temperatures around 50°F (10°C) and daytime temperatures in the range of 60-65°F (16-18°C) are important for blooming. Without this period of cool weather in fall, the plant won’t bloom nearly as well. 

Fortunately, the space around most windows is slightly cooler at night than during the day when the sun warms everything up. Choose a spot that is away from heating vents that will interfere with this natural occurrence. This will ensure good bud development and a strong blooming season.

Give It Plenty of Light

Gardenias love full sun to partial shade. Their glossy, evergreen leaves require a lot of light to maintain their lovely color. If you keep your plant indoors all year, you probably have a space where your shrub is happily soaking in the rays. However, if you’re bringing in a potted outdoor gardenia for the winter, find a space that gets as much bright light as possible. If you notice the spot where it usually lives is not getting as much light, consider moving it to a south-facing window for the colder months. 

Remember to consider the temperature when you choose a location. Keep it away from heat sources and out of rooms that typically remain warm. Light is more important than temperature, but a combination of both factors will encourage that big spring bloom.

Feed It

Remember that your potted gardenia needs less care in the winter, as it is semi-dormant while living indoors. Though it continues to need you to meet its sunlight needs, it won’t appreciate fertilizer during this time. Too much will burn the roots, as they can’t absorb as much as they usually do while semi-dormant. 

Gardenias are heavy feeders, and they set buds in the early fall. In general, they won’t need many nutrients in the fall. You don’t want to encourage a ton of new growth that could become damaged if it happens to be outdoors in a cold snap. 

Wait until late winter or early spring and give your plant a light application of fertilizer. Use a fertilizer that is higher in potassium and phosphorus. These shrubs are acid-loving, so use a fertilizer made for this purpose. Azalea fertilizer works well for these, too. Raising the acidity makes important nutrients like iron and copper more usable for your gardenia. 

Raise the Humidity

These evergreens originate in tropical and subtropical climates. Potted gardenias prefer an environment with higher-than-average humidity— around 60% is ideal, but that can be difficult indoors, especially in the winter. When the air outside is cold and dry, and the heat is running, humidity in the house decreases.  

While it may have been fine during the summer, your shrub is likely to benefit from some additional moisture in the air during this time. Keeping it away from heating vents is a good place to start, but you’ll probably want to add some moisture back into the air. 

You can raise the humidity in several ways. For me, the easiest way is to move my tropicals into the bathroom for the winter. Along with regular showers, the air in there remains more humid than in other rooms. This only works if you have a sunny bathroom window, though.

A humidifier is an effective way to raise the moisture in the air in other rooms in the house. I like to keep one going in several rooms of my home any time we run the heat. Dry air is hard on humans, too. Add some moisture back into the air to keep your houseplants and your sinuses happy.

The third way to get some moisture in the air around your gardenia is with a pebble tray. If you’re dealing with a single plant, this is the most convenient way to go, but if you have a roomful of them, this can be laborious. A pebble tray is just what it sounds like.

Place the pot near a tray that is larger than the container. Put pebbles on the tray, and then fill it with water just so it doesn’t touch the bottom. As the water evaporates, it will increase the moisture in the air just around that plant. 

Misting isn’t a terrible practice, but it doesn’t always work. With plants that need a significant amount of moisture in the air, you’d have to mist several times daily. 

Don’t Forget to Water

While your potted gardenia’s water needs decrease during its winter semi-dormancy, they don’t go away completely. These are moisture lovers, and when their soil dries out, they’re none too pleased. The tricky part is that if you give them too much water to take in, the water will sit in the soil and promote fungal disease or root rot. 

Since it’s difficult to tell exactly how much water is enough, monitoring the soil is the best way to make the determination. The amount of light, the size of the container, and the surrounding temperature will factor into how quickly it uses water. Check the soil regularly and water any time the top inch is dry.

Keep Up With Pest Control

It’s important to watch for signs of pests and diseases while your potted gardenia spends winter inside. This is not just for the health of your gardenia but also for the rest of your indoor plants. If your shrub was outdoors for the summer, make sure you’re not bringing any unwelcome visitors in with it.

Treat any issues sparingly, trying to disturb the plant as little as possible. It’s resting, so it will heal and recover slower than usual while the rapid growth is on hold. Remove any affected foliage and treat with dormant oil if you suspect an insect issue. 

Hold Off On Pruning

Winter is not the time to prune potted gardenias. While it won’t harm the plant to do so while it’s indoors, it will interfere with the next blooming season. They set buds in the fall, so the ideal time to prune is immediately after they finish blooming in the late summer. Pruning in winter will remove buds.

Don’t Overdo it

You want to find a balance between continued care and letting the plant rest. The word “semi-“ in semi-dormant is key to winter care for potted gardenias. Hold off on fertilizer in the fall and early winter, and give it a light application as winter draws to a close and spring approaches.