Bonsai Trees Care

Named by Linnaeus in 1735 in accolade of the Jesuit priest and naturalist Georg Josef Kamel, Camellia is a genus originating mainly from China but with a scope covering a big region of South East Asia. The precise amount of species is not clear-cut but it is someplace around 100. Camellia is a significant commercial genus because of one species, Camellia sinensis, the plant from which tea is made.
gardeners recognise two main groups of camellias, the autumn flowering and the spring flowering. However, it is not quite that simple. Whenever a genus of many species (such as
Rhododendron, Rosa or Camellia) is used to produce a multitude of hybrids distinct groups tend to form.

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.

Cultivation
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.

Disbudding
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.

Propagation
Camellias are not always easy to propagate without specialised 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.

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. Specialised methods, such as seed grafts, are sometimes used but these are for genuine enthusiasts that are prepared to experiment.

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.

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.

About the Author:
I am a garden book author and horticultural photographer based in Christchurch, New Zealand. I run a stock photo library called Country, Farm and Garden (www.cfgphoto.com). This article may be re-published provided this information is published with it and is clearly visible.
Tag: Bonsai Tree Trimming

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