Camellia is a genus originating mainly from China but with a range covering a large area of South East Asia. The exact number of species is not clear but it is somewhere around 100. Camellia is an important commercial genus because of one species, Camellia sinensis, the plant from which tea is made. Most gardeners recognize two main groups of camellias, the fall flowering and the spring flowering. However, it is not quite that simple.
Camellias are evergreen and small trees up to 20 meters tall. Their leaves are alternately arranged, simple, thick, serrated, and usually glossy. There are four main camellia groups: Japonica, Reticulata, Sasanqua and Hybrid, with a number of smaller groups based around less common species, such as Camellia hiemalis, and inter-specific hybrids, such as Camellia × williamsii (Camellia japonica × Camellia saluensis).
It's a commonly held belief among gardeners that Sansanquas are the autumn flowering camellias while the rest are spring flowerers. That's not really true, certainly the Sasanquas are usually the first to bloom but with careful selection and siting it is possible to have more or less continuous flowering from early autumn to late spring.
Camellias are often associated with rhododendrons and azaleas and, while not that closely related, they certainly prefer similar conditions. This is not at all surprising as they come from similar climates and can often be found growing together in the wild.
Camellias are generally less tolerant of extreme cold than the hardiest rhododendrons but they are by no means fussy plants. Most species and hybrids are hardy throughout the country, needing no protection except perhaps in very cold winter areas, and the summers here are
not usually hot and dry enough to cause much damage.
To get the best out of your camellias it is important that you follow the same soil preparation methods as recommended for rhododendrons. Camellias have stronger and deeper roots but they still require the same moist, humus filled, loose, well-oxygenated topsoil if they are to thrive. Likewise regular mulching is always beneficial.
Camellias prefer a neutral to acid soil and will not tolerate the extreme acidity that most rhododendrons will. On highly acid soils the addition of small amounts of dolomite lime will not only increase the pH but will allow easier uptake of nutrients.
Once established most camellias seem to get by quite well without too much attention but they are subject to the same chlorosis problems as rhododendrons so occasional supplementary feeding is recommended. Containerised camellias should be fed regularly as they are far more subject to deficiencies due to their limited root spread.
Camellias do best in sheltered positions in light shade or where they get only morning sun. This is not so much for the plant's sake as the flowers'. The plants will tolerate exposed sunny sites but the flowers won't. Too dense shade will promote lank growth and reduce flowering. Too sunny and the flowers will burn and drop prematurely. A site that is exposed to strong winds will dramatically shorten the life of any flowers but especially camellias.
Many camellias set large quantities of flower buds that often result in densely crowded small bloom. Thinning out the more densely packed and weaker flower buds will produce larger blooms of better shape.
Camellias are not always easy to propagate without specialized equipment. Seed germinates well but is of limited usefulness as it can only be used to raise new cultivars or to propagate species. Selected forms must be propagated vegetatively.
Cuttings should be taken just as the new growth is hardening off. This is usually around the end of November. Take new tip growth cuttings that are about 100-150 mm long and follow the procedures outlined in the propagation chapter. The cuttings may take several months to strike without mist or bottom heat.
Layering is very successful with camellias but frequently there are no branches close enough to ground level to layer. In such cases aerial layering is a reliable, if slow, method.
Camellia × williamsii
Occasionally a camellia cultivar fails to perform well on its own roots. In which case grafting onto a more vigorous stock may be necessary. Standard camellias are nearly always produced by grafting rather than simply training a standard stem.
Cleft grafting is the usual method used, however, saddle grafts and side wedges will work too. Budding is seldom used but there is no reason why it shouldn't be successful. Specialized methods, such as seed grafts, are sometimes used but these are for genuine enthusiasts that are prepared to experiment.
Camellia × williamsii 'Brigadoon'
Pests and diseases
Camellias are relatively disease free but you may occasionally encounter one of the following problems.
Viral diseases. These are quite common among camellias, in fact, viruses are sometimes deliberately introduced to obtain variegated flowers and foliage. The most common virus shows up as a bright yellow leaf margin. This is known as virus induced variegation. In minor cases it does little harm but it can weaken a plant by reducing the amount of available chlorophyll. Virus diseases cannot be cured, once infected the plant remains infected.
Phytophthora root rot. This disease affects many types of plants, particularly those that prefer acid woodland conditions. This fungus disease kills the plant's roots, which leads to the characteristic wilted appearance and ultimately death. Generally the symptoms are not obvious until too late. Prevention through ensuring that the soil is well drained is the best method. Plants can sometimes be saved by washing off the soil, removing the dead roots, drenching with fungicide then replanting in a well-drained position but it's seldom worth the effort.
Leaf gall. A fungal disease similar to that seen on evergreen azaleas occasionally occurs on camellias. It causes a thickening and distorting of the leaves, which is eventually become white with fungal spores. Remove any affected leaves and spray the plant with a fungicide. Do not allow affected leaves to drop near the plant.
Petal blight. This fungal disease cause the flowers to degenerate to watery mush and can damage much of the crop. Control with fungicides prior to bud break and remove any fallen petals from around infected bushes.
Die-back. This can be a serious, even fatal, problem. The foliage of young branches wilts and browns then the stem begins to die back from the tip. A canker develops that eventually ringbarks the stem causing its death. If the cankers spread to the main stems the plant may die. Treatment with fungicides will help but is not entirely successful. Overcrowding, poor drainage and poor ventilation can all contribute to this problem as well as making the spread of the disease easier.
Camellias are generally not attacked by any particularly unusual insect pests, just the run of the mill, aphids, scale, caterpillars, leaf rollers and thrips. The usual control measures are effective on camellias too.
Camellia Yurys Yellow
Bagworms can cause significant damage at times. The leaf covered silken bags (see illustration) are made by the larvae and the flightless adult females of the moth Liothula omnivora. The larvae feed from within the bag, which they carry around with them for protection and camouflage. Hand picking is the simplest control, the use of insecticides is not warranted except in cases of severe infestation.
Training. Besides their normal bushy habit many camellias are suitable subjects for training. The most common forms are the standard and the espalier.
Standards can be created in two ways. The easiest is to select a young plant with a single straight stem and simply remove the lower foliage and any side shoots as they appear. Stake the main stem as it grows and once it has reached the desired height nip out the tip growth to induce the branching that will eventually form the head.
The process can be speeded up by grafting but the mechanics are not as simple. Select a vigorous upright plant that will rapidly produce the standard trunk and graft your selected cultivar onto it at the desired height. Cleft grafts are the preferred method for camellias but I have found side wedge grafts to be successful. Grafting is the only practical way to produce a weeping standard.
Espaliering is just a matter of selecting an appropriate plant and having the patience to wait long enough to see the results. There are several methods of training the branches to achieve the best coverage but most camellias with thin pliable stems (primarily Sasanquas) can be espaliered with little effort. Remember though, camellias are not natural climbers, espaliers need to be secured to the structure against which they are growing.
Camellias in containers
Camellias adapt well to container growing but they are quick to show signs of nutrient deficiencies. Nothing looks less appealing than a badly chlorotic camellia in a tiny pot. However, with regular fertilizing and the right sized containers camellias will thrive and bloom heavily in pots.
As with all container plants, remember that their roots are far less insulated from the elements than those of plants in the open ground. Make sure containerised camellias get regular water in summer and in cold winter areas move the containers to sheltered positions for winter to avoid having the soil freeze solid.
Camellias are available in several different flower forms. The descriptions in this book are kept as simple as possible but occasionally the technical terms must be used. The terms single, semi-double and double are familiar and fairly self-explanatory but most of the following terms are peculiar to camellia cultivation.