Introduction to camellia cultivation.

By Jennifer Trehane

From their beginnings as wild plants growing in the Chinese, Japanese and South Korean countryside, camellias have come a long way, quite literally in many cases. They can be found in gardens almost all over the world, as a glance at the regions in which ICS members live tells us.

The first camellias to be cultivated, possibly around 5000 years ago, were tea plants, camellia species local to the area whose young shoots and leaves have been traditionally plucked to make the world famous beverage, particularly Camellia sinensis var sinensis  which is widely distributed in China.

Selections from other wild species with more beautiful flowers particularly Camellia japonica but also Camellia reticulata in Yunnan, China, were later made to grace the gardens of temples and those of the nobility. This was done hundreds, probably more than 1000 years ago. As more were selected they were crossed with each other and the first cultivars emerged and gradually filtered out of China and Japan to ‘the west’. The first named cultivars arrived in England in the 1730’s on the tea clipper, the Carnatic. (the story appears elsewhere on the website).

At first, in England, it was believed that camellias were ‘exotics’, to be housed in heated glasshouses, and proudly displayed by their wealthy owners.

They became highly prized and sought after.

Interest spread throughout Europe, especially when it was realised that these plants were actually successful outdoors.

By the middle of the 19th century camellia cultivation was widespread. Hybridists and nurseries in Belgium, Holland, Germany, Italy, France, Portugal, Spain and the UK were breeding, propagating and selling more and more camellia plants in more and more varieties. This was also the century when camellias were spreading with increased enthusiasm in North America, New Zealand and Australia and hybridists produced ever more exotic varieties which soon triggered competition amongst gardeners. Camellia Shows became regular events and camellias, especially in the USA started to be collected and grown specifically to produce blooms for the shows. Local societies cropped up around this trend and enthusiasts learned the techniques needed for this type of cultivation, which is very different from that required to grow camellias as garden plants for overall enjoyment.

Gardening with camellias-  How ? Why ? Where ? and When ?

It’s a good idea to look to ‘origins’ to find out what to provide when considering camellias for a garden, wherever this may be in the world. Plus a bit of detective work locally to find out more, particularly when it comes to choosing varieties.

Site

In the wild most camellias grow in communities either in semi-shade provided by a canopy of trees, particularly pines in China, or they grow upwards to become small trees themselves, effectively forming camellia woodland as happens with Camellia japonica, ‘tsubaki’, in many parts of the Japanese archipelago, and Camellia sasanqua, ‘sasanka’, in southern Japan. Camellia reticulata may be found in full sun in China but is more often seen in semi-shade.

Most camellias need good light to thrive and to form flower buds, but prefer some shade to give protection to both flowers and leaves, especially in hot climates where mid-day sun may scorch leaves and bleach the colour from flowers or even cause them and their buds to shrivel up and fail. Where trees are not available to provide natural shade, shade structures are built.   

Protection from strong winds, hot or cold, is also highly desirable.

Soil

For those of us brought up to grow camellias in light textured composts based on peat, cotton seed waste or other coarse organic material, or planted in garden situations with plenty of organic matter, it is surprising to see wild camellias in China growing in dense, ‘heavy’ soils with a high percentage of small clay particles.  These are admittedly mostly found on well drained slopes and in a climate with low winter rainfall so roots are less vulnerable to rotting. Similar soils are used in the clay pots used as containers both in the nurseries and around houses, but root systems are not vigorous and plants slow to establish and grow into healthy plants.

In most gardens around the world camellias thrive in slightly acidic soil with a texture providing good drainage, with air round the roots. As camellias grow they form deep roots for anchorage, a spreading fibrous root system to absorb water and nutrients and---surface roots, which become more obvious as plants reach maturity..

Water.

In their natural environments camellias receive very little water in winter when they are dormant. Most of the rain falls during the monsoon season, which starts just when temperatures rise and they come into growth in the Spring. Developing leaves and shoots need plenty of water and nutrients transported up from the soil in that water. Most flower buds form on the current year’s growth from mid-summer. From then onwards they need a regular supply of water for the development of the flowers within the buds and for the flower stalks that attach the flowers to the stems. A break in water supply during these months may result in fallen flower buds and a lack of blooms later.

Natural rainwater is mildly acidic, which suits camellias just fine. If it can be stored for use later that is ideal. If this is not possible or supplies run out, what then ? What if the household water supply is alkaline, say pH8 or higher ?

In temperate climates with significant rain falling in summer this is not a problem, especially for camellias planted out in the garden. Tap water is better than no water for short term situations. Its a different matter where long, dry summers are the rule.

Mulching, either with an organic material such as woodchips or with a plastic membrane to reduce evaporation is often used. Regular irrigation is usually needed. Where there are only a few plants this is done by hand, giving a good soak from a water can or hose, making sure the water reaches right down to the roots. With a collection of plants it’s a good idea to instal an irrigation system. Many enthusiasts in hot dry climates such as in California and parts of Australia, instal irrigation systems with timers set to provide water in the evening or overnight when there is low evaporation, and often the added bonus of discounted payments. Acidifying kits are available if required.  

Feeding.

In the wild camellias grow from seeds and need very small amounts of nutrient to start with, supplied by rotting leaves and other plant material around them, gradually increasing as they grow. It’s all balanced out naturally and they grow relatively slowly.

When cultivated it’s a different matter. Plants are usually bought from nurseries in pots, usually already growing vigorously. In order to keep the momentum, young camellias planted in the garden appreciate some fertiliser to help get them established. Applied during the growing season, either as a regular liquid feed, a less regular granular feed, or as ‘slow release’ pellets supplied once in Spring and possible again in mid-summer, these fertilisers need to be added with care. Overfeeding can kill.

Why feed in the Spring ?

Camellias, like many woody plants, stop growing in the autumn and go into a period of relative inactivity, (dormancy). Leaves stop manufacturing the sugars needed for normal activity and ‘the sap’ (liquid sugars), stops moving through the plants; they are gradually stored as immobile starch granules, just under the bark. So---feeding during the dormant season is usually a waste of money, but experienced camellia enthusiasts in the Showing fraternity in warmer climates where dormancy may not be complete, do sometimes fertilise their plants in late winter, in order to enhance the colour of their blooms.

Generally a camellia, especially those that are of a variety classified as ‘formal double’ or ‘peony form’ and ‘large’ or ‘very large’ will also produce bigger blooms, with more petals in warm climates and may be disappointing in cooler areas.

The burden of carrying a crop of flowers is quite a heavy one and the energy for doing this usually comes from activation, helped by enzymes, of the starch store and its gradual conversion into sugars. By the end of the spring flowering season many camellias are showing signs of exhaustion and look less than healthy. Their stored nutrient reserves may be used up, but growth buds are activated and the usual surge of spring growth needs more energy. Added nutrients are appreciated.

There are many types of fertiliser available in different parts of the world so local advice and knowledge are useful.

Wherever they are, camellias need a balanced diet of the main elements, nitrogen, phosphorus and potassium plus iron, magnesium, sulphur, and calcium and a variety of more minor elements. All interact within the plants to help with their metabolism and are able to be taken in and put to good use when the soil is acidic, pH7 or below.

As the years go by, provided the soil conditions are suitable, the roots will spread and they will usually find sufficient nutrients once well established and with sufficient water to conduct them into the plants.

Choice of varieties.

There are varieties available for almost any garden situation, in a range of flower sizes, shapes and colours. Some are vigorous with sturdy stems and quite quickly grow to become small trees. At the other extreme there are slow growing camellias with dense growth habits that are either upright or spreading. Many come somewhere between the two. Local nurseries and garden stores will have a selection and should be able to provide advice to help choose for local conditions, as will Camellia Society members at Camellia Shows.

The ICS Register featured on this website provides good descriptions of over 40,000 registered cultivars.

Planting camellias.

Good ground preparation gives camellia plants a good foundation so its a good idea to spend time in advance of planting, removing all perennial weeds, incorporating well rotted organic matter in an area about 1 meter square and a spades depth for each plant

Make sure that after planting and firming the soil the camellia is not planted too deeply.

They need air around the neck of the plants, where the stem joins the root system. Many young, newly planted camellias are killed by lack of air here, which causes rotting and the death of vessels carrying water and nutrients up from the soil and sugars down from their manufacture in the leaves.

Tall plants may need the support of a stake and ties, to prevent the wind rocking them, disturbing the roots while they are trying to get established.

 
 

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