Because camellia growers enjoy a wider range of cultivars than what Nature will allow in a marginal climate (as in the Washington, DC., area), some cultivars will benefit being protected from winter’s winds and temperatures.
Dehydration is a big killer of camellias; however, with proper precautions more sensitive cultivars can endure the winter and give enjoyment to the grower. Depending on how the camellias are grown, there are basically two forms of protection – outside of a greenhouse – that will allow the plants to survive a harsh winter.
If the camellias are planted in the ground, they are best grown 3 to 6 feet from the foundation of a house where the warmth of the house can aid in the protection. Also, by constructing cylinders made of 2″ mesh wire as supports for burlap covering around the plant, and filling it with about 6″ of dry OAK LEAVES (depending on the size of the plant – about 1/3 of the depth in leaves), the camellias will be partially insulated against the winter winds that cause a burn effect. Some light must reach the upper part of the plant to sustain adequate photosynthesis activity and to avoid condensation and rotting from damp leaves.
If available, DuPontCompany’s MICROFOAM thermal blanket (1/4″ thick) may be used. Either wrapped around the wire cylinder or supported by at least 3 stakes, and fastened with twine. The top is fastened tightly shut with clothespins. This protection does not rely on leaves within the enclosure, as it relies on heat from the ground. MICROFOAM allows light and some moisture to penetrate. Leaves may be piled around the outside perimeter 4 to 6″ high and out about 1 foot or more. The enclosure is put on in November (in Zone 6) and removed in March, depending upon the weather. We, in Maryland, USA, have been using MICROFOAM for 20 years and find it is an excellent protection for camellias. Some of the plants may have blooms on them. The top of the cylinder is opened for several days before the MICROFOAM is removed completely. ; We recommend using MICROFOAM for the first year or two until the roots get established, on the cold hardy camellias. For growers wishing to raise more tender commercial varieities, MICROFOAM is put on every year. This is a great way to protect the buds and get nice blooms. If the camellias are grown in container, simply lay the plants on their sides and cover with MICROFOAM which acts as a blanket. A sheet of MICROFOAM will be more effective if it is sandwiched between two sheets of 4 mil clear plastic. All edges of the “blanket” are weighted down with bricks, etc., to seal in moisture and to provide insulation. Plants should be covered before any hard freezes and uncovered in the spring. The most tender of cultivars have successfully endured the winter using this method. Furthermore, do not be surprised to find blooms on the plants when the covering is removed.