Those who live in USDA hardiness zones 11 to 12 often don’t have to worry about overwintering their gardens.
However, keeping plants alive and healthy throughout the cold months can be something of a challenge for the rest of us.
Care requirements tend to be quite different while the plant goes through a dormant phase.
Hibiscus (hi-BIS-kus) is a genus of 300 species, many of which are succulent or tropical.
While some species are grown as annuals, many others are perennials that can last for years with the proper winter care.
Here’s everything you need to know to keep your hibiscus plant alive and well throughout the cold months.
Hibiscus Winter Care
Overwintering generally requires changes to 3 major care factors:
- Temperature
- Water
- Feeding
Mastering these three things is slightly different for indoor and outdoor plants but equally easy to carry out once you know what to do.
Annual Or Perennial? Sometimes YOU Decide
This is something that’s often forgotten when talking about overwintering plants.
Most garden plants can live for 2 years.
Examples of these include:
- Biennials (carrots or foxgloves)
- Perennials
This is also true of most species of hibiscus, although some species are grown as annuals.
It’s entirely possible to grow many perennial species of hibiscus as annuals by doing the following:
- Gathering seeds
- Cuttings in the fall
- Allowing the mother plant to die
This is a convenient way to reduce the winter workload for many while also preventing their plants from getting too big.
But to get the most out of your hibiscus, you will want to keep it alive so that it will come back bigger and better in the next year.
Of course, whether or not you choose to overwinter your hibiscus is entirely a matter of personal preference, but it’s good to know you have that choice.
Overwintering Indoors
Let’s start with the easier method of overwintering hibiscus plants indoors.
In most cases, this refers to a potted plant, but some gardeners may actually uproot their garden specimens and bring them indoors.
Tropical hibiscus and many other types cannot handle temperatures below 32° degrees Fahrenheit.
These plants have the best chance of survival if you uproot them and bring them indoors before the temperatures start dropping below 50° degrees Fahrenheit.
Temperature
Make sure your overwintering hibiscus plants are in a sunny spot of the house where temperatures stay above 50° degrees Fahrenheit and preferably around 60° degrees Fahrenheit.
If all the leaves fall off, but the stems remain pliable, your plant has gone into full dormancy.
When this happens, move it to a cooler spot with low light (50° degrees Fahrenheit is fine here), so it will remain dormant until spring and conserve its energy.
Whether or not it goes fully dormant, avoid areas where they’ll be exposed to sudden temperature changes or drafts, such as near vents or a frequently used door.
Food
Overwintering hibiscus plants tend to conserve their energy and will often go completely dormant.
Even a somewhat active hibiscus will need this time to rest, so avoid giving the plant food until you see new growth appearing in the spring.
Water
It is one of the easiest places to slip, as the hibiscus needs less water during its dormant period.
Keeping your summer watering schedule can damage the roots and even lead to root rot or stem rot.
If you’re using the soak and dry method (and we hope you are), you can use the same technique all year round because you’re only giving the plant as much water as it needs.
Additional Notes
When overwintering hibiscus indoors, it’s not unusual to see some leaves turning yellow or falling off.
This happens because the plant is conserving its energy and doesn’t need or want so much foliage using up energy to try and photosynthesize from the weaker winter sun.
The number of leaves affected might be mild, moderate, or even total, depending on the species and level of dormancy.
Overwintering Outdoors
Outdoor plants will take a little more effort to prepare for winter, but hardy hibiscus plants can survive some pretty harsh winters if you prepare them properly.
Cutting Back
One important step unique to outdoor plants is cutting them back.
Wait for the first killing frost, when some of the leaves of plants turn brown, before attempting to cut back.
Here are the following tips for cutting:
- Use sharp, sterile shears to cut off all of the year’s growth until the stems are 1’ foot above the ground.
- Some hardy hibiscus can even be cut back to ground level, but avoid doing this to hybrids and cultivars, or it may grow back as one of the parent plants due to how they are often grafted).
This reduces the number of plants exposed to freezing winds and encourages fuller new growth the following spring.
Winter Proofing
Obviously, you can’t control the temperature outside, but you can take some steps to protect your plant.
- You can build a clear plastic tent over the plant, but be sure to weigh down the edges so it won’t blow away to help hold heat in.
- Alternatively (and perhaps preferably), you may choose to add an 8″ to 12″ inches layer of pine needles or chopped leaves over the ground around the plant.
Not only will this keep the roots and stems warm, but it will decay over the next few months, leaving the soil much richer come spring.
Of course, you can also choose to use both methods.
Food
Avoid using fertilizer in the winter for your outdoor plants.
Remember, they’re hibernating, and the food could cause them to wake up too early and produce fragile new growth that could kill the plant.
Water
Give the plant one last, really good watering before the first frost.
You likely won’t have to water an outdoor plant again until spring, and doing so could freeze the roots.
Instead, just let the winter rain and snow do the watering for you.