Hidden Valley Hibiscus
Growers & Hybridizers of Exotic, Tropical Hibiscus
Plant Care
Pruning Hibiscus
Spring is usually the time one thinks of pruning but for those with hibiscus which have not been pruned recently, it may be time to consider doing so. The benefits are better shaped plant, increased branching with increased blooms, reduction of insect load that is over-wintering on the branches to be pruned, re-invigorates the plant as growth hormones activate the lateral buds that have been dormant. There are some drawbacks too as you will see no blooms on the pruned branch for a couple of months. Also temporarily smaller, shorter, or out of balance plant until the new growth fills in.
 Hibiscus 'High Voltage' Pruning Encourages More Flowers |
How To Do It:
· Thoroughly clean and sterilize a pair of sharp by-pass pruning shears such as the HVH Recommended Pruning Shears. For sterilizing, we favor an alcohol gel that is available as a water-free hand cleaner in most grocery stores. Squeeze some of this onto a clean rag and wipe the blades clean frequently as you prune. If you cut into dead or dying wood, your pruners will need to be sterilized before making the next cut. Rubbing alcohol, bleach and water, nursery products such as Physan, or hydrogen peroxide can all be used to sterilize pruners. Take your time after applying the sterilizer to the blades before wiping it off. Most sterilizing materials need 15 seconds or more to kill disease-causing organisms, so let it do its job before wiping it away.
· Take a good look at the plant to be pruned. Because the new growth will start below any cut you make, you want to plan accordingly. Cutting a few inches off the top is usually not a good idea, as the new growth sprouting off the end of the existing branch will not look quite right.
· Instead, plan to cut most branches back by about 1/3 or even more, always leaving at least 2-3 nodes (bumps on the stems where leaves once grew) on each branch. The new growth that emerges will be strong and will blend in with the rest of the plant.
· Choose a long or out of proportion branch to start with. Look about 1/3 of the way down the branch until you find a leaf node (eye) that is facing the direction you want the new branch to grow. Up or out is usually better than down or inward facing.
· Make the cut just above the eye that you located, leaving about 1/4" of wood between the eye and the cut.
· If your pruners are sharp, the cut will be smooth and not strip the wood or bark from the stem. Try to avoid doing so if possible.
· Move on to the next branch and repeat. Hibiscus are very resilient and will actually grow better after this treatment, so do not hesitate to make those cuts.
· Take a final look, as it is still possible to cut the pruned branches even further back if that appears desirable for shaping purposes.
 Hibiscus 'Piña Colada' Pruning forces new branches, Flowers bloom on each new branch. |
Some strategies for pruning:
1. Cut back only the longest branches during one session, leaving several shorter or side branches for another time. This will assure that you have blooms on this plant both early in summer and later when the new growth comes in. Repeat the following year.
2. In early spring some people prefer to cut the entire plant way back, leaving only thick wood and a few leaves on several main branches. By midsummer the plants will be completely renewed and will bloom from then until fall temperatures slow them down.
3. Other people prefer to only prune branches that grow way out of proportion or those that flop to one side, leaving all the other branches alone so that they will have blooms as early and late as possible. The drawback to this is that the plants will not develop as many branches as they would if they were pruned, so there will be fewer total blooms. Also over time the older wood will tend to bloom less and less.
Timing - When To Do It
The time to prune depends on where you live and the weather you expect. The main precaution is not to prune so that the tender new growth is emerging during a time when frost is likely. This guideline dictates that most pruning be done between late February and August, depending on local conditions. If partial or selective pruning is practiced, there is no real drawback to pruning at any time within that period. Complete cutting back of the plant is best done in early spring only.
Pruning a Damaged Hibiscus
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, 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.
Finding a Suitable Node
 Hibiscus Nodes One with a Leaf |
You've Pruned, So Now What?
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 the new growth will come back. During that time keep the hibiscus evenly moist if possible, and fertilize it at half strength once per week. If you notice any insects on the bushes, it is important to get rid of them so that the tender new shoots that are coming will not be damaged by such insects. I was surprised to find spider mites on one of my outdoor hibiscus only a few weeks after we had the freezing nights! You can use forceful water sprays such as with the Bug Blaster or apply Clean Leaf as part of a clean-up program. Applying worm castings or other soil improving materials to pots or ground is a good idea during this time. Growth stimulants such as our Wake-up Spray or Seaweed Concentrate are also excellent to use after pruning.
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 the fertilizer being used, as well as the amount of water the hibiscus receive. Stay vigilant for insect attack or use routine treatments on the plants as a preventive.
That's it! Pruning hibiscus is not a difficult job, and will produce fantastic results in terms of plant shape, health, and increased blooming. Just follow the simple steps above, and choose the best time of year to do it according to your local weather conditions.