Organic Articles

You are welcome to read and use our articles
provided they are unchanged and the Author information remains the same.
Thank You

Bonsai
Article Snippets
Article Index

Camellias

Author: Geoff Bryant

Camellias

Named by linnaeus in 1735 in honour of the Jesuit priest and naturalist Georg Josef Kamel, 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 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.

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.

Other special forms.

Camellias can make effective hedges, either tightly clipped or grown informally. As might be expected of a genus that contains the tea plant camellias can withstand frequent trimming when actively growing.

Some camellias are suitable for use as ground covers but usually only while they are young. In time all but the most prostrate forms will develop into mounding bushes rather than true ground covers. Pegging the branches down as the plants grow is the only way to ensure this doesn't happen.

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 fertilising 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.

Flower forms

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-doubleand double are familiar and fairly self-explanatory but most of the following terms are peculiar to camellia cultivation.

Anemone

A style with large outer petals and massed small central petaloids.

Peony (paeony) and informal double

Large outer petals and smaller loosely clustered central petals and petaloids. The more fully petalled flowers are known as full peony form.

Rose form double

A double flower that opens fully to reveal the stamens, like a fully blown rose.

Formal double

This flower type has perfectly arranged concentric circles of neatly overlapping petals. Some have the petals in a very clearly defined spiral pattern.

There are also rules governing the terms used to describe the size of flowers but as most non-specialist gardeners find these to be more confusing than useful they have not been strictly adhered to.

Species and cultivars

The following selection of species and cultivars includes those most popular for garden use or that have interesting or unusual features. They are divided into hybrid groups.

Species

These are the most popular or influential of the species but they are not widely available in nurseries, most gardeners preferring the hybrids.

Camellia chrysantha (China)

A yellow camellia was a long sought after aim of plant breeders, hence the basically white cultivars with optimistic names such as 'Brushfield's Yellow'. However, in 1980 a real yellow camellia was found in the Guangxi province of China. It flowered for the first time in the West in 1984 and has since been the subject of great interest and speculation among camellia growers. It is a large species that can reach 5 m high. The large leaves are deep green and heavily veined. The bright yellow flowers are only about 60 mm diameter but it is not the size of the flowers but their potential for hybridising that initially had breeders so enthused. Reasonably hardy but prefers consistent cool to moderate temperatures, intolerant of extremes. Camellia societies have a few plants of this species but even now it is not generally available through garden centres.

Camellia forrestii (China, Vietnam)

A large shrub or small tree native with narrow elliptical leaves and small white flowers that are mildly fragrant. Early to mid season.

Camellia fraterna (China)

Grows to about 5 m high. Small elliptical leaves. 25 mm diameter white flowers with white stamens and prominent gold anthers. Slightly fragrant. Not totally hardy. Flowers mid season.

Camellia granthamiana (Hong Kong)

Very rare in the wild; known, until recently, from just one plant found in 1955. It may be a natural hybrid rather than a true species. Grows to about 3 m high. Deep green heavily veined elliptical leaves up to 200 mm long. Creamy white flowers up to 150 mm diameter with massed golden stamens. Flowers early. Not totally hardy.

Camellia hiemalis (Japan)

Not known in the wild and probably a natural hybrid between Camellia japonica and Camellia sasanqua . Grows to about 3.5 m high. 30 mm diameter pale pink flowers with golden stamens. Small to medium sized elliptical leaves. Flowers early.

Camellia kissi (North East India to Southern China)

May grow as high as 12 m but usually consideably smaller. Medium sized narrow leaves. Small white flowers that are usually fragrant. Flowers mid season to late.

Camellia lutchuensis (Southern Japan including Okinawa)/FO ...