For too many years, camellias have been limited to regions along the Atlantic seaboard from Norfolk, Virginia, southward and the Gulf Coast and the West Coast of the United States; too mild areas of England, France, Portugal, Spain, Italy, New Zealand, and Australia and to temperate Asia.
Because there are now so many reports of successful plantings in “unsuited” areas, it is necessary at this time to extend the old limits for outdoor growing.
New Frontiers for Camellias
Camellias of many varieties and species are thriving in gardens in lath houses at the National Arboretum in Washington, D. C., and in numerous private gardens in the District of Columbia. Camellias are thriving in gardens in Philadelphia, Atlantic City, Long Island, and indeed, as far north as Toronto, Canada.
I know of two plants that for nearly ten years have been growing outdoors with only minimum protection in a rural area of Kansas. At present, Camellia japonica seems to be the hardiest species with C. saluenensis, C. hienialis, C. Vernalis, and certain hybrids.’ Camellia sasanqua is next in hardiness, while C. reticulata is the least hardy of all.
Many camellias can take subzero temperatures for long periods without harm. However, many old plants were killed along the South Atlantic seaboard in 1950 when the temperature there dropped to 16 degrees F. And in 1958, temperatures of 12 degrees in Washington and Oregon killed many old specimens.
Survival depends on the time it takes temperatures to fall. The South Atlantic freeze of 1950 was on November 24. The temperature at noon was 70 degrees F. with a storm front approaching.
By midnight, it had dropped to 16 degrees killing century-old camellias, azaleas, and many other ornamentals which had never before been harmed there. The Washington-Oregon freeze of 1958 was similar, with the temperature falling very fast.
In central areas and along the Northern Atlantic seaboard, winter usually comes gradually with several weeks of light frosts before a heavy freeze. This conditions plants gradually and makes them harder.
Tubbed Camellias Can Be Grown Anywhere
Growing camellias in containers is becoming a more and more popular way to enjoy them, and the method has many advantages, especially where outdoor conditions are not ideal. Container plants can, of course, be moved in and out with the seasons.
They can be placed prominently while in bloom and be removed to make way for something else when not in bloom. Collectors can grow many more varieties in containers than in a limited space in the ground. Furthermore, growing media and nutrients can be closely controlled.
For practical purposes, the temperature range for most hybrids of Camellia japonica and C. saluenensis is 5 degrees below zero to 115 degrees F. above, the optimum, between 38 and 80 degrees F. Humidity tolerance is from 10 percent for a short while to the infinite maximum, with the ideal 50 to 60 percent.
Camellias in the garden need about 40 inches of rainfall a year, and this is evenly distributed. In sandy soils, they need more, and in heavy soils a little less. Where natural moisture in the proper range does not prevail, irrigation with good-quality water can be arranged, or drainage installed to lead off excess water.
If you grow camellias in containers, watering will require the development of know-how so that plants do not get too much water or stiffer from too little. Keep in mind that camellias in containers are completely dependent upon you for their care.
Not Exacting Soil Requirements
Soil requirements are not too exacting, although good drainage is necessary. Soils rich in humus and acid reactions are ideal. They can be developed by mixing desirable ingredients. Drainage requirements can be met by the use of tile, or by digging through a hardpan or other obstruction and backfilling with coarse gravel.
Most species and varieties require some protection from the hot sun and strong winds at least during their young years. In many areas, the ideal situation is under the protection of high-branching trees, such as evergreen or live oaks, pines, or some small-leafed trees, or on the protected side of buildings, or in shade structures.
The shade should not be dense. Allow at least half and half-light and shade. There is a triple advantage in planting under trees:
- Protection from intense sun
- Conservation of moisture by reduced evaporation and transpiration
- Natural provision of mulch and humus from falling leaves and twigs. Of course, a little extra plant food and water should be provided for the trees.
In areas of high humidity, overhead protection is usually not required. Even in arid southern California, except in the hottest regions, it is not necessary to provide shade for reticulatas, most varieties of Camellia sasanqua, and certain varieties of C. japonica.
When exposed to full sun, plants usually become a lighter green than if grown in shade. This slight color loss has no adverse effect on vigor. But if leaves turn yellow or appear scorched, they either lack nutrients or are sunburnt.
Shade can be produced artificially by various means, depending on the materials available. If protection is necessary for only a few days or weeks during a hot spell, simply erect a four-cornered pole or post arrangement around the plants and stretch cloth—burlap, cheesecloth, or plastic shading—over them.
Ways To Provide Shade for Camellias
For more permanent shade, you can plant trees, shading your plants temporarily with a cloth until the trees reach sufficient size, or you can construct a permanent structure, a wooden or aluminum lath house, or a plastic cloth house.
The most permanent and most expensive shade structure is the aluminum lath house. These structures are manufactured by various companies and can be bought to fit almost any space or architectural style.
Lath houses of wood are practical and can be built from materials easily available in any area. Lath should not be over 2 inches wide and structures should be erected with strips running north and south so the rays of the sun will change position on the leaves as it goes over. Lath panels can be made in easily handled sections and tied with wire so they will not blow off in wind.
Plastic Shading Cloth Is Highly Recommended
Plastic shade cloth is one of the best and most economical modern answers to shading. Available by brand names everywhere, it is the easiest to handle and is made in various degrees of shade density. Distributors will cut and bind it to specifications, placing grommets around double-bound edges if necessary.
It can be fastened to guy wires with hog rings in any shape desired. It can be used in any situation where canvas could be stretched, or it can be permanently affixed to pipe or wood structures. Plastic shade cloth should be stretched tight and supported every 10 feet or so to protect it from wind damage. Most growers prefer shade structures 10 to 12 feet high.
In areas too cold to meet camellia requirements, there are two possible courses of action: (1) Simply grow the plants in tubs, wooden boxes, or cans, plain or fancy as you wish, moving them inside the house or basement as required; or (2) Construct a house suitable to growing plants of any size desired, providing heat and humidity as necessary to satisfy their needs.
Either way, it is important to give adequate light. Inside camellias should be placed before a bright window or provided with artificial light for 10 to 12 hours a day. Use either incandescent lamps or fluorescent lights placed about 3 feet above the plants and bright enough to simulate outdoor conditions.
For instance, regulation 100-watt lamps should be spaced about 4’ feet apart on a grid over the plants.
A house constructed just for plants may be of any size from a simple four-post affair for one plant up to a large greenhouse. I heard of an ancient camellia in Dresden, Germany, which was nearly 30’ feet tall and 30’ feet wide.
It is protected by a structure covered with glass panels, which are removed during warm periods and replaced in winter. It is heated by a simple steam heater extended from a nearby building.
In colder sections of the United States, gardeners in recent years have used individual enclosures with wooden or metal frames covered with Fiberglass panels or other plastic material. These simple structures are easily removed in spring and replaced in winter.
Heat is provided by any convenient means to keep the temperature above the freezing point. Two or three 100-watt electric lamps will give adequate protection in most small structures unless it is extremely cold.
Teepees for Camellias
Enclosures should be wide enough to check encroachment of ground frost from outside. This can be arranged by making a teepee-like structure, wide at the base with poles joined and tied together at the top, the whole covered with heavy plastic sheets. Fiberglass panels can be laid over plants growing against the side of a building.
New developments in the Fiberglass industry make it possible to construct a Quonset-type hut by merely securing foundation boards to the ground, parallel to each other, 10 or 12 feet apart, and arching flat, not corrugated Fiberglass panels between them. Strong bonding or adhesive materials are manufactured to hold the panels together.
Guy wires over the house anchored by “dead men” will secure the structure to the ground. The ends of the Quonset-type house may be sealed for winter with strong plastic sheets or permanent ends made of flat Fiberglas where doors can be installed.
It is possible to select an exact candlepower-rated Fiberglas which will eliminate the necessity of shading the structure during hot periods. Various research institutions have proved that Fiberglass and plastic are as efficient, if not more so than glass for growing plants. Certainly, construction methods are practical and more economical.
In growing camellias inside any structure, you must be fully responsible for them. Plants require regular attention. Moisture must be provided on an even and consistent basis and nutrients supplied according to the needs of the plant.
How To Add Humidity
Humidity control is vital, particularly in a heated structure. A humidistat and means of humidifying should be a part of all structures. Humidifiers may be anything from a pan of water on top of a heater to an automatic fogger. Whatever system is used, it should maintain humidity near the normal range.
Ventilation, that is some exchange of air, is essential every day, but care must be taken to maintain proper temperature and humidity during the airing. The period of ventilation may vary from a moment on a cold, damp day to all day in bright, warm weather, or 24 hours a day in slimmer weather.
Ventilation may be using an open window through manually-controlled ventilators on top of a greenhouse, or with an automatic clock-controlled device. Camellias will not bloom well if grown at constantly high temperatures. They must have periods of chilling to simulate the normal winter temperatures of their native lands.
Don’t Give Camellias a Sunburn
Control of sunlight is also essential. A glass or plastic house can cause sunburn in hot weather if plants are not properly shaded. Shading is usually done by spraying the outside with whitewash or paint, or by placing lath or shade cloth over the top. If you purchase Fiberglas, be sure it is candlepower-rated.
Growing camellias in a house or greenhouse are not as exacting as orchids and some tropicals. Camellias will tolerate a wider range of humidity and temperature and greater extremes of light and shade. But do simulate good outdoor growing weather as close as possible.
Sterile-Soil Culture for Camellias
California researchers have developed a method of sterile-soil culture that may be of benefit to greenhouse camellias. It consists of growing in a mixture of 2 parts washed sharp sand, 1 part each coarse peat and redwood sawdust.’ All these materials are easy to handle and contain no fungi or diseases.
However, they are devoid of nutrients. With this mix, consistent applications of complete plant food are essential. The fertilizer should contain the three basic nutrients of nitrogen, phosphorus, and potash and also the complete range of secondary and minor elements including iron, magnesium, manganese, zinc, copper, boron, cobalt, and fifteen or twenty others.
Fertilizers, either dry or in solution should be applied at a consistent rate the year around. Nearly all major fertilizer manufacturers make plant food to fit this need.
This method of culture is strongly recommended for greenhouse-growing because with it you can avoid many complications of disease and insect control as well as drainage and nutrient problems due to unknown elements in garden soil.
The sterile-soil method, coupled with day-extension by artificial light can force seedlings and young plants to grow and bloom at an accelerated pace. If forcing lights are used, it is better to have them clock-controlled to come on about 2:00 a.m. and burn until the sun is up than to give continuous light.
On cloudy days lights could be kept on. Camellia seedlings can be brought to bloom in approximately 18 months by this method compared to 6 to 7 years without forcing.
44659 by Elvin Mcdonald