Hibiscus species native to tropical climates have shallow roots and, hence, they adapt excellently in pots or containers. In fact, container plants are said to be particularly adaptable when grown in confined areas. Potted tropical hibiscus plants are ideal for people who live in apartments and do their gardening in balconies or those who move house quite frequently. Growing tropical hibiscus in pots enables the gardeners to exhibit them when the plants are at their best, and take them away at other times. At the same time, people who live in places having cold climatic conditions have no option, but to grow hibiscus in containers.
Various types of containers are available in the market and it is advisable that you opt for pots that are equally wide and deep or preferably wider than their depth. It is important to grow hibiscus in wide containers because the delicate feeder roots of these plants expand from the stem base much in the form of a wheel's spoke, but nearly horizontally. In fact, hibiscus plants have additional fine feeder roots compared to the anchoring roots that grow downwards into the ground. Hence, narrow containers are absolutely unsuitable for growing hibiscus plants. While it is alright to grow hibiscus in plastic pots, but they heat up where the climatic conditions are very warm, eventually damaging the roots. Moreover, it is important to ensure that one side of the pot does not heat up, while the other side remains cool. Therefore, if you are living in places having warmer climates, it is always safer to put the plastic pots inside other bigger pots. Many people, who grow hibiscus professionally, suggest using terracotta pots instead of plastic pots because the clay-fried pots are not "glazed" and, hence, enable the plants to "breathe". Alternatively, you may also use pots made from concrete or stone. In fact, timber pots are also excellent for growing hibiscus, provided they can retain moisture. Containers made from cedar wood as well as wooden wine barrels serve this purpose excellently. Although hibiscus plants grown in pots are heavy, they have a very gentle growth habit. Different from the plants having robustly growing roots, which require repotting very soon or planting outdoors, the roots of hibiscus never break open their pots. Many other plants, such as shrubs, orchids, agapanthus that have fleshy roots and bulbous plants with exploratory or expansive roots can often break the containers. On the other hand, when the roots of hibiscus grow to their limit, they automatically begin to defer growth. When the roots reach the perimeter of the pot or container and grown downwards along the sides, they slowly start filling up the center of the pots.
A container that is roughly 12 inches to 24 inches (30 cm to 60 cm) at the top and has a slightly narrower base is ideal for growing a medium sized hibiscus, which may grow up to a height of 6 feet (2 meters). Ideally, the height and the width of the containers should be almost the same. Hibiscus grows well in pots having more width than height, but never be comfortable in containers that are higher than wider. This is primarily owing to the fact that if a pot is tall and narrow, its space at the bottom is wasted, while the area at the top is too narrow for the plant's growth. Therefore, it is advisable that you should start with a pot having a width of 12 inches to 16 inches (30 cm to 40 cm) at the base. This will allow the plant to grow in the same pot for several years, following which you can report the hibiscus in a bigger container.
While growing hibiscus in pots, you should ensure that the drainage system is such that it allows additional water to pass, but retains the solid and nutrients. Ideally, the drainage holes ought to be in the pot's external perimeter, instead of being below. Or the drainage holes may be in both places because, in the long run, the matted roots below can block the drainage. This is more likely to happen in the case of pots that are placed on saucers. Therefore, it is advisable that you place the pots on a somewhat raised platform made using broken bricks, terracotta tiles or the likes. In fact, saucers are very useful when placed underneath pots kept indoors and also for frequent watering when you are absent. When you are not there to water the potted plants, you may leave some water in the shallow saucers with a view to keep the plants cool in extremely hot weather conditions. However, generally speaking, as it is necessary to have a sharp drainage, potted hibiscus plants require regular watering and side drainage.
The potting mix should be highly porous and, therefore, it is always necessary to include some amount of sand in it. The type of sand that is most suited for this purpose is called 'sharp' sand, which denotes the surface of each sand particle or grain. Sand that is made up of sharp grains, instead of smoothed grains is actually derived from granite and this type of sand grains is ideal for air-filled porousness. In addition, the potting mix should also be loose and friable. Therefore, it is best to have a blend of 80 percent potting mix (generally pine bark dust) and 20 percent "sharp" sand. Alternatively, you may also use a blend of superior quality commercial potting mix and garden loam with an equal amount of sand. Moreover, you may also include a little amount of properly aged compost in the potting mix. Nevertheless, you should be careful that the compost does not have any worm, for worms obstruct drainage. Apart from sand, you may also add a little measure of fine peat, instead of the compost. If you are using a potting mix that does not contain soil, it will also not have any trace elements. Therefore, you need to supply these trace elements by means of a slow-release or medium-release fertilizer. However, the best thing to do is using some amount of compost in all types of potting mix. Be careful only to use a small amount, otherwise you may apply the compost in the form of surface mulch. You may also use well decomposed manure to provide the mulch covering.
If you are contemplating to grow hibiscus in pots, you should always opt for dense and luxuriant plants. In fact, it is essential to avoid plants that are tall, lanky or scraggy. While it is possible to control the size of a plant by pruning it, it is always preferable to purchase a relatively smaller bush to begin with - if possible get a plant having a thick branching tendency and copious foliage.
After you have filled three-fourth of the container with the potting mix or planting media, place the hibiscus in the desired position. Be careful not to damage or compress the roots in the process. At the same time, ensure that you do not plant the hibiscus very deeply, but keep the plant's root and stem joint near the surface of the soil. Now, add the remaining mix close to the brim of the pot. Next, pat down the mix lightly so that there is a space of about 1 inch to 1 1/2 inch (3 cm to 4 cm) at the top. Remember, you should never fill the pot completely up to the top. When this is done, water the soil properly. After the plant settles, the level of the soil may decrease to some extent and then you may put a slight layer of mulch. Mulching the plant is not essential, but definitely beneficial.
In case you are employing slow-release fertilizer, such as pellets or coated granules, you may require feeding the hibiscus plant with these nourishments at least two times each year - once during spring and then in early fall. If you are living in a place having cool climatic conditions and growing small plants, it will be sufficient to apply the fertilizers just once a year. On the other hand, if you are applying any liquid foliar spray, you need to feed the plant more frequently - no less than once in two to three weeks, especially all through the growing season. As far as watering the potted hibiscus is concerned, you need to water the plants only when they require it. Scrape the surface of the soil to a depth of roughly 3/4 inch to 1 inch (2 cm to 3 cm) and if you find that the soil is moist underneath, don't water the plant. On the other hand, if you find the soil to be arid, water the plant thoroughly using a hose. It is necessary to water the plants adequately after feeding them with nutriments (fertilizers).
The plant's size is usually controlled by the dimension of the pot. For instance, if your container's diameter is about 12 inches to 24 inches (30 cm to 60 cm), the hibiscus plant will usually grow up to a height of 5 feet (1.5 meters) from the pot's base and measure roughly 39 inches to 51 inches (1 meter to 1.3 meters) across. Perhaps, this size is apt for any gardener to handle properly. In reality, it is always preferable to have a plant of a smaller size. Provided you have a preference for a smaller shrub-like hibiscus plant, simply cut it back. However, many gardeners are not aware of the fact that when they prune the foliage, their plant also prunes its root by itself. For instance, if you reduce the size of the plant to a height of approximately 20 inches (50 cm), the decrease in the foliage will prompt the feeding roots to retract inside the soil. While retracting, the feeder roots leave behind minute air tunnels in the potting mix, something similar to tunnels made by worms, but narrower. Irrespective of whether it is a potted plant or a large shrub-like plant growing in the open garden, the roots will always retract in this manner. In the case of larger bushes in the garden, the feeding roots spread out to the drip line of the leaves in such a way that the external dimensions of the plant help the gardener to determine the roots' external perimeter. You should never feed your hibiscus plant when its roots are retracting or reducing themselves, because the roots are not able to absorb the nutrients when they are retracting. During this time, the plant draws its nutrients from the carbohydrates it has amassed within itself, while the air tunnels created by the retracting roots provide it with adequate air. Therefore, if you find a spurt in new growths after you have pruned the plant radically, you should know that such growths are being supported by the plant's stored energy and not from the nutrients contained in the soil. In fact, pruning the hibiscus bush with a view to spruce the roots is a superbly tidy system, especially for the home gardeners. While this is a reliable means to maintain the shape of potted hibiscus for several years and can be repeated a number of times, eventually the plant will require a fresh growing medium for invigorating the hibiscus. It is worth mentioning here that the roots' color manifests the overall health of the plant. While white roots mean that the plant is growing robustly, when the roots have a darker hue, it is an indication that the condition of the plant is not good. While you are repotting the plant, ensure that you use a new pot that is just one size larger than the previous one.
When the roots of your potted hibiscus plant have grown large and became visible through the drainage holes, you should know that it is time to repot the plant in a larger container - always the next size of pot. On the other hand, the appearance of the plant shows that it has consumed all the nutrients supplied to it and it needs to be fed again. While repotting the plant to a larger pot, you need to be extra careful so as to prevent any damage to the roots. Scrape the potting mix of the old pot, gently take out the plant and position it in the potting mix of the new pot. Ensure that the root and stem joint of the plant are at the level of the surface. Dissimilar to other different root-bound plants, which respond excellently to teasing their matted roots, hibiscus plants will only tolerate very tender handling of the roots.