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4. Using Hibiscus

Apart from the long flowering season and wealth of colour and form of the blooms, the hibiscus has many advantages over most other evergreen shrubs. It can be used in many different ways to improve the landscaping of a home, factory or park.

The Aesthetic Value of Hibiscus

There is nothing more exhilarating to see and enjoy than the many bright and happy colours which stand out from a massed bed of hibiscus plants in full bloom.

Apart from the sight being good for the eye, it is surely good for the spirit also. Some of the colours are so intense and bright that one cannot help but marvel.

There is a colour to suit all tastes: from the very delicate soft pinks, creams and whites, right through to the bright reds, oranges and yellows, and on to the multicolours, where the combinations never cease to amaze. Lavenders varying from deep to soft hues blend in beautifully as do the unusual coffee brown and tan shades. It is hard to imagine a brown or tan flower, but when contrasted with lush green foliage they make an attractive sight. These are not everyone's taste but they certainly appeal to many people.

Planted as individual specimens, on their own or near a featured light or other garden ornament such as a pond or selected boulder, the hibiscus can be most pleasing.

In some cases the foliage of some varieties is appealing, and some are featured for this reason, as the leaves vary so much in texture, shape and colour. There are some with variegated foliage, the best most probably being `Snow Queen', a delightful blend of white and cream variegated leaves that often have delicate pink tonings as well. When grown properly this variety develops a weeping habit that adds to its aesthetic appeal.

`Andersonii" is a variety that has handsome brownish purple autumn tone foliage, that contrasts so well with the pendulous, brilliantscarlet blooms. `Fijian White' has a glossy light green leaf that is shaped like a maple leaf, and is a beautiful foliage plant.

All varieties differ in their characteristics, and each individual plant's outstanding features should be shown to best advantage if we are to really appreciate the aesthetic value of hibiscus!

Hedges

For many years, hibiscus hedges have been very popular in tropical regions particularly Hawaii, where the lush green shrubs are covered with red polka dots, like something designed for an old-fashioned stage set. The current trend toward living fences has one searching for suitable plants, and for this situation, provided of course full sun is plentiful, hibiscus are ideal because of their long flowering season and reasonably rapid growth. For formal hedges, the one variety should be used for conformity of leaf and growth. Informal hedges may include several varieties of similar heights and growth habits. When used for windbreaks the strong types should be chosen and staked well until established. Hedges ranging in height from one to six metres (3 to 20 ft) are possible simply by choosing the right variety.

The plants should be spaced at the right intervals to allow for maximum coverage, but still leaving enough room for cultivation around the base. To ensure speedy coverage it is advisable to prepare a nice rich garden bed the length of the hedge rather than planting in holes.

Hedge height

Low hedges 1 - 1.5 m (3 - 4 ft)
Medium hedges 1.5 - 2.5 m (4 - 7 ft)
Tall hedges 2.5 - 4 m (7 - 12 ft)
Very tall hedges 4 - 6 m (12 - 20 ft)
Spacing

0.7 1 m (2 - 3 ft)
1 - 1.6 m (3 - 5 ft)
1.6 - 2 m (5 - 6 ft)
2 - 2.5 m (6 - 7 ft)
 
Upright growing varieties may be planted closer to ensure better coverage.

Standards

The art of standardising plants dates back many years and is usually associated with roses and weeping cherries, however more recently azaleas, fuchsias and bougainvilleas are being offered by nurseries in a standard form. A standard plant is simply a plant that has been elevated on a straight stem to a desired height before the laterals are allowed to grow to produce the canopy. Selected cultivars of hibiscus also make handsome standards, and when trained correctly produce outstanding specimens. If you are unable to purchase an already standardised plant, then you may train your own. Select a plant with a good straight stem or a group of plants can be placed in a shaded glasshouse very close together to induce them to compete for light and produce elongated growth. When hardened off this is ideal for the trunk of a standard plant. A height of one to two metres (3 - 6 ft) should be allowed before the laterals are grown out to produce the main canopy. When the height has been determined all subsequent lateral growth arising from below this point should be taken off as close as possible to the stem with a sharp knife. The plants should be staked securely, and often an underplanting of other dwarf plants adds to the effect, providing that they do not rob the hibiscus of essential nutrients. The variety chosen to be standardised may be grafted onto a nice straight understock the required height. Weeping or prostrate types are suitable as well as the bushier ones.

Espalier

This is a different and unusual way to grow a hibiscus. The idea is to train the plant with its trunk and branches flattened in the one plane. This form of culture takes some time to achieve the desired effect. Start with a suitable specimen, preferably one with a straight main stem and strong sturdy side shoots at regular intervals. The plant is then trained to the required shape against a wall or fence and securely fixed to same (see line drawing).

There are many varieties suitable for espalier work; the main points to look for are long willowly growth, and stems that can be twisted and bent into shape without breaking. These include:

'Agnes Galt'
`Bruceii'
`Boondah'
`Camdenii'
`Copper Queen'
'Celia'
`Cindy'
`D.J. O'Brien'
'Julius Camfield'
`Rose Scott'
`Mrs Tomkins'
`General Corteges'
`The President'
`Delight'
`Dainty Pink & White'
`Ross Estey'
`Wrightii'
`Wilmae'
`White Kalakaua'
'Vasco'
`Catavki'
`The Bride'
`Primrose'

Hibiscus in Containers

Although hibiscus are considered outdoor garden shrubs, the increasing number of apartment dwellers who have no garden space available and of people who must limit their gardening has created a demand for information on how to grow hibiscus in containers. This information is needed not only by apartment dwellers living in colder climates where hibiscus are not usually grown, but by the ever increasing number of those apartment residents in the warmer climates. Furthermore swimming pool surrounds, sunny patios and verandahs, balconies and terraces can be enhanced by the placement of beautiful hibiscus in containers.

Though hibiscus will grow in a variety of soils, they do best in soil mixes containing high levels of organic matter such as peat. A good hibiscus potting mix should never be heavy, but light and porous so that the water will quickly run through the pot and out the bottom. The mix should have a texture which will allow both water and air to pass through readily and yet retain some moisture. A mixture of 2 parts sandy loam, 1 part coarse river sand, 1 part cow manure, mushroom compost, spent hops, garden compost or horse manure, and 1 part peat moss is ideal for hibiscus, but other mixes of soil, peat, perlite and coarse sand are equally good if not as substantial.

Packaged potting mixes from local garden centres and nurseries, whilst good for most plants, are not suitable for hibiscus, for they contain far too much inert organic matter which holds too much moisture for hibiscus. These potting mixes should only be used if mixed with soil and sand to give a more evenly balanced texture, or unless the label specifies that it is suitable. Good garden soil with a little peat, cow manure and sand mixed with it is usually better and more inexpensive than buying potting mixes. Soilless mixes consisting of various combinations of peat moss, perlite, and vermiculite are light, easy to handle and sterile, however a regular watering and fertilising program must be strictly adhered to or else the plants lose condition. These soilless mixtures are better if confined to glasshouse or indoor culture.

Hibiscus seem happy in almost any kind of container, be it of clay, cement, plastic, metal or wood. The choice is up to the grower's preference. Wooden tubs should never be treated with creosote or other wood preserving materials as these are toxic to plants; lining with black plastic will help to preserve the timber and keep the plants healthy. Side drain holes are preferable to bottom drain holes as these tend to block when placed on flat surfaces, particularly after a period of time. If you intend to move the plants under cover in winter, you will find that plastic containers are much lighter and easier to handle than heavy concrete ones. The size of the containers can vary from 25 cm (10 in) to 50 cm (20 in) depending on the size of plants being grown. By starting off in a small size container and re potting into a larger size when necessary you will keep your plants healthier and more vigorous than by placing a small plant into a very large container to begin with. You will be compensated for the extra work in re potting by the extra blooms and healthier growth.

It is important that plenty of drainage material is placed at the bottom of the container. This material can be old broken terra cotta tiles or pots, rubble, stones or coarse clinker ashes. Care must be taken not to obstruct the drainage holes which must be left clear to allow for the passage of water. The drainage material should be placed in the container to a height equivalent to one quarter of the container's height and covered with a layer of fine coke ash or wood shavings before the soil is placed in. Hibiscus appear to prefer wider shallower pots than long deep ones. Ones with straight sides make re potting easier than Grecian urn or Ali Baba kinds.

Hibiscus in containers dislike saucers that fill with water under them. If you wish to have saucers under them to protect your patio, empty them after the plant has drained. Containers with holes on the bottom block when placed on smooth flat surfaces. Place small wedges about 6 mm ( in) thick under the container to allow easy passage of water. Flat fibro is ideal for this. Do not elevate your container on house bricks as these are too high and your plant will dry out too rapidly, particularly in windy weather.

As plants in containers need more watering than ones in the ground, the nutrients are leached out more rapidly; therefore more fertiliser is required to keep the plants healthy and productive. Many hibiscus growers with container grown plants use a soluble fertiliser as often as once a week, however it is recommended that a regular hibiscus fertiliser be applied once a fortnight or every three weeks. Never fill the container right to the top with soil, leave about 7.5 cm (3 in) from the top. This will allow you to place cow manure, spent mushroom compost, garden compost or other organic material over the soil to provide the necessary humus to keep the plants healthy. A drip or trickle feed watering system is an excellent way to keep the containers moist and prevent the plants drying out when the grower is away for any length of time.

Pests are few and far between on patio grown hibiscus. Sometimes aphids or spider mites will creep in from outside or be brought in by other plants and cut flowers. A horticultural spray can or garden type insecticide will usually take care of these and will alleviate the problem of mixing messy sprays for just a couple of plants. Caterpillars, snails, grasshoppers and other larger pests can easily be caught and will not require spraying in a limited area or on only one or two plants.

The best time for re potting hibiscus is in the spring, immediately after pruning. When the plants are cut back they are easier to handle and they respond quickly to the fresh soil once re potted. Plants may be re potted at other times except winter without ill effects.

Remember you can grow any variety you wish in a container, but the smaller, lower growing varieties will last longer than fast growing tall varieties, and will not require such large containers.

Hibiscus Indoors

If you live in an area where the Chinese hibiscus will not do well, then you could try growing these plants indoors. To perform well, hibiscus require full sun, so they must have sunlight streaming through a window onto them, otherwise they will need extra artificial light to flower well. As with many indoor plants, it is better to buy a plant from your garden centre all ready to bloom, as it is very difficult to encourage buds to form without ideal conditions which are hard to produce indoors. Once the plant has finished blooming it is then discarded, and replaced with a new plant the following season. Many nurseries in Europe and the United States grow special, prolificly blooming hibiscus, especially to be used as indoor plants. These plants are grown in glasshouses and treated with growth retardents, usually Cycocel or Chlormequat, and are sold as flowering indoor plants. The growth retardents restrict the growth to small pot size without the loss of flowering wood which would result from pruning. Many keen hibiscus fanciers in problem areas grow their plants in pots, and bring them indoors during winter, returning them to the garden sunshine as the weather warms; others prefer to erect a cold frame or small glass house for this purpose.

One of the most popular indoor foliage plants is Hibiscus rosa-sinensis `Cooperii', which has beautiful variegated cream and pink foliage. This variety rarely flowers, but has small single red blooms when it does. The more light it receives the more spectacular the pink tonings in the leaf. Variety `Snow Queen', a sport of `Archerii', is a lot hardier and does well indoors, flowering quite well. Here again the variegation is more pronounced as more light is available. This variety has handsome green and white variegated foliage, and pendulous, fringed, single, bright scarlet blooms. Most hibiscus have flat dull leaves which will attract dust. These must be kept clean if the hibiscus is to remain healthy indoors, and regular watering and fertilising is necessary to keep the buds coming on. The colour of the blooms on hibiscus grown indoors will not be as vibrant or bright as the ones grown outdoors, due to the lack of sunlight, therefore it is always a good idea to choose bright colours. The varieties offered by nurseries for indoor use include: `Crown of Bohemia', `Fiesta', `General Corteges', `Lambertii', `Johnsonii', `Surfrider', `Golden Belle', `Nathan Charles' and `Gold'.

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