Hibiscus Plant Care
Help for Hibiscus Damaged by Cold
Nothing feels more tragic than seeing your beautiful hibiscus garden get decimated by freeze damage. Tips of branches wilt and die, and the poor plants can end up looking like dead sticks covered with wilted leaves. What do you do?
If your plants are in pots, bring them inside. Warmth is the first and most important thing you can do for your plants. Ideally they should come into a bright room but not in direct sunlight. If you don't have the ideal situation, bring them inside anyway. Warmth is more important than the type of sunlight! Use Houseplant Formula on your plants all through the winter and spring. It is our best possible formula for sick plants and will pull your hibiscus through the stress they have undergone more quickly than anything else you can use.
If your plants are in the ground, then provide some warmth for them outside. String Christmas lights around the plants, the old-fashioned incandescent type if you still have them. They provide more heat than the new LED lights. Be sure to use outdoor certified lights and outdoor extension cords. Then cover the plant and lights with freeze cloth, which you can buy inexpensively at any garden center or hardware store. You don't need to remove the lights and freeze cloth. Just leave them on until all danger of frost is past.
Another way to provide warmth if your hibiscus are up against a house or fence is to tack plastic over them and fashion a mini greenhouse.
If a freeze catches you by surprise and your hibiscus are uncovered outside, turn sprinklers on them and leave them on all through the freezing night. Turn the water on high enough that it will sprinkle each whole hibiscus plant and really soak the whole plant. In the morning, your plants will be covered in ice ~ a scary sight for sure! But even ice helps insulate plants and keep them warmer in a freeze.
As long as there is danger of frost, resist the urge to prune your plants or remove the wilted leaves. Provide warmth and leave the plants alone for now.
Growth Enhancer and Fertilizer
Growth Enhancer can work wonders for cold-damaged plants! If you haven't tried it yet, this is the time to try it. It is the first line of defense for any sick, damaged, or stressed plant, and if there is anything left to save in your plant, Growth Enhancer will save it. Don't forget to keep using fertilizer too. Even if the top part of the plant is not growing, the roots need to keep growing underground, and the more vigorous root growth is, the more hormones your plant will churn out, and eventually the more top growth you will see. So continue to use both Growth Enhancer and fertilizer all through the winter months. Or if you prefer, you can simply use Houseplant Formula. It has both fertilizer and Growth Enhancer, along with many other nutrients, in the optimum doses for sick or stressed plants.
Now it's Spring ~ Time to Clean Up and Prune
Be sure to have plenty of water-free hand cleaner with you because you will need to sterilize your pruners after every cut into damaged wood. Once you start pruning, you'll also need to collect all dead, possibly diseased wood and put it in a plastic trash bag. You want to send all bad wood off to the dump in plastic bags rather than leave it lying around where it can spread disease back to your healthy hibiscus plants.
Checking for Live Wood
First check your plants for dead stems and branches. The test is simple enough. Working from the tip of each plant stem down toward the base, use a strong fingernail or a small knife to make a small scratch test (1/4-1/2 inch long). Scrape away a tiny bit of the brown outer bark of the stem that you are not sure about and look at the color underneath. A live branch will be bright green underneath the bark. If the branch is brown or light tan, it is dead. Some dead stems may be rotten, soft and squishy to the touch. There's no need to do a scratch test on stems that are soft and squishy - they are clearly rotting and dead. Just keep working your way down the stem, doing scratch tests, until you find the point where scratching away the bark reveals bright, healthy, green plant tissue underneath. Plant tissue that is dull green with brown mixed in is not likely to live, so keep moving your way down the branch until you find a bright green patch. Now that we know where the live wood begins, it's time to remove the dead wood.
Removing the Dead Wood - Two Strategies
Deeply Pruned Hibiscus Branch
Cut has clean, white wood inside bark.
New growth is sprouting below.
The second pruning strategy is to shape the plant while removing the dead wood. You start the same way, by finding the point where the wood is clean, green, and white. Instead of cutting just above the first clean, healthy node, the cut is made further down, just above a node that is pointing in the direction you would like a stem to grow. Be sure and cut 1/4 inch above the node, so that there is room for the new stem to sprout. If the cut is too high, the remaining wood above the node may rot. If the cut is too close to the node, you may remove the special plant cells that would have sprouted into the new branch. In this second pruning strategy, you remove more wood than is necessary to eliminate the dead wood. Some of what is removed will be white and clean but the idea is to force more stems to sprout lower down on the bush, to help it achieve a full and attractive appearance. You may cut away as much as 2/3 or even more of a branch in order to do this. Don't be afraid to prune back many of the stems severely. The plant will re-grow with more branches than ever before and look fuller than ever before. More branches mean more flowers, too!
Some of the dead wood on a hibiscus bush will just be twigs. Remove the dead twigs as close to the branch they were growing from as possible without damaging that branch. Throw them in a trash bag in order to dispose of them.
Helping Your Hibiscus Come out of Dormancy
After cleaning up your hibiscus by removing all dead wood and pruning some branches for shape, what do you do? It will take several weeks, depending on weather, before your hibiscus will come out of dormancy and new growth will come back. During that time keep the hibiscus evenly moist if possible, and keep fertilizing and using Growth Enhancer.
To speed up the start of new growth, you can additionally spray your plants with Wake-Up Spray. Spray as often as daily until each new growing tip has its first set of real leaves, then cut down your spraying to once per week for 2-3 weeks more, then stop using Wake-Up Spray and let the Growth Enhancer and fertilizer do their work alone.
Hibiscus thrive on attention, and many of the cold-damaged plants from a cold winter will come roaring back to bloom again in the summer if they are given a little tender loving care as they recover from winter. As the temperature warms and summer approaches, increase your fertilizer and water, and add in Hibiscus Booster to increase growth and get your plants fully ready to start blooming. Stay vigilant for insect attack or use routine treatments on the plants as a preventive.