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Hibiscus Plant Care

Potting & Planting Hibiscus

You just got your first exotic hibiscus plants, and now your first decision is whether to keep the hibiscus potted or to plant it in the ground. Hibiscus are tropical plants, so if you live in a place that freezes in the winter, the answer is an easy one - keep your hibiscus in pots that can be moved to a warm spot during winter freezes. If you live in a warm place that rarely freezes, and just barely hits 32° one or two nights per year at the most, then you have the option of planting your hibiscus in the ground. There are good reasons to keep them potted, such as being able to move them around, but we have also found that hibiscus do very well when planted in the ground in warm climates.

Planting Hibiscus in the Ground

Exotic Hibiscus Flowers
In Warm Areas Hibiscus Thrive in the Ground
Before you plunk your hibiscus in the ground, it is important to spend a little time selecting and preparing the planting hole. Never forget the gardening wisdom of the ages, "It's better to place a $5 plant in a $20 hole than a $20 plant in a $5 hole." Here are two simple tests you can do to make sure you are planting into a hibiscus-safe spot:

Test your Drainage: Test the hole to be sure it drains by pouring a gallon or so of water into it. If the water disappears within an hour that is good enough. If it is still standing there after an hour you are probably planting into clay or over some other impermeable material, and may end up drowning the hibiscus roots. Alternatives are to build up a raised planting bed or to amend the soil with "clay-busting" material available at most nurseries. If the hole drains well, plant the hibiscus fairly deep, covering the original root ball with a couple of inches of soil as you fill in the hole.

Test Water Permeation: Test to see how well water soaks into your soil by digging a small well into the top of the ground. Fill the well with water 2 or 3 times and let it drain away for half an hour or so. Then dig into the soil, and look at the water line to see how far down the water has soaked. If the water is moist 8-10" down, then your soil has good permeability and it's safe to plant hibiscus in it. If only the top inch or two of the ground is moist, your soil does not have good water permeability, and your hibiscus could die of drought, no matter how much you water, because the soil resists soaking up any water you pour onto it. Before you plant your hibiscus, you will need to dig a very large hole that you fill with a high quality planting mix, allowing plenty of extra room for the hibiscus to grow roots into.

Super Sandy Soil: If your soil is very sandy, you will probably have problems growing hibiscus in it. Very sandy soil does not absorb much water or hold fertilizer. Most of the water applied to sand flows down past plant roots, and the water that is absorbed evaporates quickly. If you have very sandy soil either grow your hibiscus in pots, or be prepared to water often and use timed-release fertilizers on the surface of the soil. You can also try amending the sandy soil with good compost and other organic ingredients so that it will hold more water and fertilizer. Check with your local Dept of Agriculture and the Master Gardeners group in your area for more advice.

Digging the Hole: The hole you dig for your hibiscus needs to be a few inches bigger than the plant pot, on all sides, if your soil is good. If you are filling the hole with planting mix, make the hole much bigger than the size of the pot. If you live in a dry place where your hibiscus could get brushed with frost and where water retention is important, plant your hibiscus deeper into the ground, with the crown of the plant, where the roots meet the trunk, an inch or two under the surface. If you live in a soggy, warm place, dig a more shallow hole to keep the crown above the surface level of the ground around the hole. The more you break up and work the ground around the hole, the more easily your hibiscus will be able to grow longer, deeper roots. So take your time, and dig a $20 hole! Then put a few inches of good soil or planting mix into the bottom of the hole for your plant to sit on.

Ready to Plant: Once your hole is prepared, water the hole to moisten the soil all through it before putting the hibiscus in it. Gently remove your hibiscus from its pot, being careful not to rip the roots away from the base of the plant. As tempting as it may be to pull on the plant trunk to get the plant out of the pot, resist the temptation. Instead, put your hands on the soil, and gently turn the plant upside down up in the air. Then hug the pot, and let gravity drop the plant out of the pot into your hands. Use your hands to break up the roots around the rootball a little bit on all sides, then position the plant in the prepared hole.

Look at your plant before you finalize the position. Look which way branches grow, and make sure you position in the direction that looks best from what will be the viewer's vantage point. If the plant has listed to one side in the pot, use this replanting opportunity to make it stand up straight again in the hole in the ground. It won't hurt the plant a bit for the roots to be put a bit sideways into the hole. Take one last look at the position of the plant, then fill it in with soil somewhat firmly, but without heavily packing or tamping it down. Water very well - deeply, 2 or 3 times to make sure it completely saturates all parts of the hole and rootball. Et voilà! You're done! Wait a week or two before beginning your fertilizing regime, then fertilize away. Hibiscus rarely experience transplant shock. They love to have room to spread out their roots, and you will often see a recently planted hibiscus stand up taller and look happier than it did in its pot!

 

Growing Hibiscus in Pots

Is it possible to keep hibiscus in small pots forever?

Many of us live in places where we can never put our hibiscus into the ground, and for us, the question is, "Can we keep hibiscus in manageable pots forever?" This is a question we are getting asked more and more, and the answer is, yes, you can keep hibiscus in small pots indefinitely. This is exactly what we do in our greenhouse with our own hibiscus collection. We have to keep our plants in pots that we can easily move around and fit close together in the always-limited space in a greenhouse. There are some tricks to making it work, but none of them are difficult.

Tropical Hibiscus 'Chariots of Fire'
Hibiscus 'Chariots of Fire' Growing in a 10" Pot

How Small Can the Pots Be?

In our greenhouse, we have found that hibiscus will grow large and stay happy for many years in pots as small as 10" in diameter. A 10" pot is convenient because it is easy to pick up and move around, and can be put in almost any location. Any size larger than 10" is of course fine too! In our houseplant testing, we are currently experimenting with keeping hibiscus in very small pots and keeping them pruned to a very compact size. So far we have been successful with smaller pots, but it is too early to tell for sure how long our plants will be happy in smaller pots. But 10" pots have worked for us for years, and we can recommend that size with certainty.

First, Potting Medium...

If you plan to keep your hibiscus in a pot, the potting mix is very important. There are inexpensive products out there offered by mass-market sellers, but in our experience this type of mix dooms hibiscus to a short life and poor performance. These mixes are often too heavy and hold too much water for hibiscus. They can also contain ingredients that are toxic to hibiscus. Recycled sewage sludge is often used in inexpensive mixes, and although it is sterilized, the trace mineral content is unknown and can be quite detrimental to hibiscus. Instead, what is needed is a soiless potting mix (contains no real soil) like the HVH Potting Mix. A good mix is made of coco coir, peat moss, or composted bark to hold moisture and nutrients, along with sand and/or perlite to provide more drainage. Added organic ingredients that support beneficial microbial life in the pot, such as worm castings, bat quano, or other fully composted organic material, are very beneficial in the potting mix. If you are unsure, we suggest going to the best nursery or garden center in your area and asking for a high quality potting mix that drains well and contains some organic materials. You can always add the organic material yourself, such as HVH Worm Castings, and should ideally do so once a year in order to maintain the beneficial microbial life in the potting mix. Using high quality potting soil for your hibiscus is a crucial step in keeping them healthy and blooming for a long time to come!

Second, Nutrition...

Hibiscus 'Simple Pleasures'
Hibiscus 'Simple Pleasures' in a 10" Pot
Anytime we keep hibiscus in less-than-perfect conditions, we need to maximize nutrition to help reduce the stress the plant experiences. Start with a good quality hibiscus fertilizer that has all the nutrients hibiscus need with as few contaminants as possible. Anything you put in your hibiscus pot is going to stay there for a very long time, unlike hibiscus planted in the ground. So be careful not to put anything into the pot that could possibly contaminate your hibiscus. Hibiscus prefer a light fertilizing on a frequent schedule, so if you have time to fertilize every time you water, this is the best possible way to keep hibiscus in small pots happy. Use 1/2 the dose on the fertilizer label each time you water, and watch carefully for signs of fertilizer burn - brown edges on otherwise healthy leaves. If you see signs of fertilizer burn, or "nitrogen burn," stop fertilizing for 2-3 weeks, then use an even weaker dose of fertilizer in your regular watering. The idea is to use as much fertilizer as you can without causing fertilizer burn.

Fertilizer Burn
Fertilizer Burn ~
Burnt Edges on
Otherwise Healthy Leaves
If you can afford it, a Growth Enhancer is another option you can add to your nutritional program for your hibiscus. Growth enhancers provide different types of nutrition than fertilizers. They are loaded with the hormones and anti-stress proteins that plants themselves produce, but a plant that is stressed by a small pot may have difficulty making enough of these hormones and proteins. Supplementing with these nutrients helps keep hibiscus at optimum health levels, and gives them a break from having to produce all these proteins themselves.

Exotic Hibiscus 'Belle du Jour'
Hibiscus 'Belle du Jour' in a 10" Pot
One other nutritional product you may want to add to your arsenal is extra potassium, such as is found in our Hibiscus Booster. Hibiscus are voracious users of potassium, and if they become deficient in this element, their flowers will slowly diminish is size, number, and color intensity until they eventually stop blooming all together. The more stressful the conditions a hibiscus lives in, the more potassium it needs. Tiny amounts of this inexpensive nutrient will keep your hibiscus blooming with lots of big, colorful flowers year after year.

Third, Pruning...

Pruning becomes extremely important when you keep a hibiscus in a small pot. The shape of the plant will be determined completely by how well you prune it. The more branches you encourage your plant to grow, the more it will flower, since hibiscus tend to produce one flower at a time on each branch. In a small pot, you need to think about which direction the branches are growing and what kind of overall shape each branch you leave on will give your plant. If you want a branch to grow up to fill a space near the top of the plant, look for a node that is on the top side of the branch you're pruning, and prune just above that node. This will force a branch to grow from that node up into the space you need filled. Try to look at each node, and imagine where a branch growing from that node will shoot out, then pick the node that looks like it will create a branch in the shape you want. It's more of an art than a science, since we constantly turn our plants in their pots and cause sunlight to shift each time we turn them, but learning to think about these things when you prune will help you shape your potted hibiscus in ways that make it more beautiful while still keeping it more compact.

Fourth, Root Pruning...

Tropical Hibiscus 'Fat Actress'
Hibiscus 'Fat Actress' in a 10" Pot
The final step in keeping potted hibiscus happy is to prune their roots every couple of years. To check your plant's roots, gently ease the pot off the rootball. If the roots are circling the bottom of the pot and form a solid mass at the bottom, it is time to prune them. Root pruning is easy: Using a very sharp knife that you have sterilized with alcohol or hand sanitizer, slice off the bottom 2 inches of the rootball. Then add 2 inches of fresh, good quality potting mix into the bottom of the pot, pop the plant back into the pot, water, and voilà! You're done! As the plant grows new roots down into the fresh soil, the new roots will stimulate growth hormones throughout the plant, and the plant will produce more top growth too.

These are the basics of keeping hibiscus happy in small pots. Our greenhouse is full of very old, very happy potted hibiscus, so we know this works! Good luck to all of you with yours!