CAMELLIA PROPAGATION
By Bradford King -
Camellias can be propagated in numerous ways: seeds, cuttings, grafting and air layering. Camellias grown from seed will vary from the parent therefore they will not be discussed here. (Check out the article "Growing Camellias from Seed")
CUTTINGS: Camellia cuttings are taken from the plant the grower wishes to reproduce. The cutting needs to be four inches with five leaves taken from new growth that is light brown not new growth green. These semi ripe cuttings are usually taken mid summer. July is a good time to do this in Southern California. The three lower leaves are removed and the two remaining leaves are cut in half to reduce water loss. The stem is cleanly cut just below a leaf axil and dipped into a growth hormone. They are place in a pot filled with equal parts sand and potting mix or peat moss. This mix should be moist but not wet. The cuttings may be placed in a green house or cold frame with bottom heat. If not available it is simple to make an individual pot into a mini greenhouse. The pot is enclosed with plastic –larger sized plastic bags, plastic from the cleaners or some other source. For example a laundry plastic bag may be used by tying a knot in the top of the plastic bag that has a small hole for the coat hanger hook. This will make the bag air tight. In order to keep the bag from collapsing on itself the coat hanger hook is removed and the wire is bent to make a U shaped bridge to support the plastic. I use two for a one gallon pot. The cuttings are labeled with a white plastic plant label. It is recommended to have the same plant cuttings in each pot. The pot is placed in a shady place that has protection from wind, pets, children and wildlife. Check on the pot regularly and add water if needed. A few sprays from a plastic spray bottle into the plastic cover are easy, provides moisture and doesn’t disturb the cuttings. If the plastic has condensation on the in side all is working well and the cuttings should be fine. Roots grow slowly and must remain in the pot until they develop. This can be determined by gently pulling on the cutting. If there is resistance the roots are holding it in place. If there is no resistance re-cover and be patient. If there are dead cuttings remove them before recovering. Depending on the varietals and conditions several months to a year may be needed for roots to develop.
CLEFT GRAFTING: Cleft grafting is usually done in February or early March depending on the weather. The under stock may be a big old camellia whose blooms are no longer desired or a pencil sized potted camellia chosen for its value as under stock. e.g. Kanjiro. In the latter case, the under stock is cut at a 45 degree angle with a sharp knife, small saw or shears and the top is squared off then split vertically and wedged open. The scion is taken from the mature wood from the camellia being propagated. Ideally this wood is from the previous year’s growth from the top of the plant. This scion is cut to a point and slipped into the open root stock. The cambium layer (the green band just beneath the bark) is matched to the cambium layer of the root stock. This matching must be accomplished for success. A rubber band is cut and wrapped around the graft to keep the scion in place. Rooting hormone is sprinkled on the graft. The graft is labeled with the name of the camellia from which the scion was taken. The graft must be kept moist at all times. This is accomplished by placing a wide mouth glass jar over the graft. Alternatively a plastic greenhouse is made as previously explained under cuttings. The graft is placed in protected shady area of the garden. In most case the graft will require additional shade. The simplest method is to cut a "window" in large paper bag 8 to 10 inches square. The plastic and the bag are held in place with a large rubber band around the base of the pot.
When using an old camellia in the ground, the trunk is cut straight across, then vertically split and wedged open. Two scions are prepared and inserted in each side of the cleft. Alternatively three or more V shaped cuts are made along the edge of the trunk exposing the cambium layer on the inside edge of the V. The scions are shaped to fit in the V snugly. In other words the scion is inserted in the V so that cambium layers are matched up. The grafts must be covered with a glass jar or clear plastic to keep a moist atmosphere. Soil is mounded around the bottom of the glass or plastic to keep the area from drying out. Usually a frame is constructed to hold the glass or plastic in place. An easy method is to use chicken wire cut to cover the scion and trunk with ample space for the scion to grow. Additional shade may also be needed. This can be provided with a paper bag as described above. If the scions and camellia trunk are too large for a bag, 50% shade cloth (more if in a sunny area) cut to size and attached to the chicken wire structure works well.
The grafts need to be monitor to be sure they remain moist. If there is condensation on the glass or plastic they are most likely fine. When the scion has new leaves, it is time to check to see if there is a scab growing at the point of the graft. When the scab is well formed, allow some air under the glass or cut the plastic to allow some air in. Do not take the top off all at once as the graft will collapse. One to two weeks of partial exposure is needed. It is recommended to mist the new graft every day or two. If the weather is hot and dry, daily morning misting may be required. Remember the graft has just been removed from a protected environment that has had constant moisture so special care is needed. The new graft may now be placed in a shady area to continue its growth. A new graft should not be fertilized its first year as this may cause the graft to die.
APPROACH GRAFTING: There are two types of approach grafting strategies. One is "stem" grafting and the other is "branch" grafting. In branch grafting a potted camellia is placed next to an established in-ground camellia. The potted plants branch is then attached to the "mother" plants branch in such a way as to make the potted plants branch grow vertically. Both of the plants are marked at the junction point.
The "mother" plants junction area is hollowed out four to six inches in such a manner that the "baby" plants trunk fits comfortably in the space. The "baby" plant limb has its bark on one side removed leaving some of the cambium layer to match with the cut edge of the "mother" plant. The two branches are snugly fitted together. The junction is tightly bound with non adhesive green plastic garden tape. These grafts do not need to be covered. In late fall the tape is removed. In spring, about one year into this process the mother plant should be pruned to leave just the new plant. A few "nurse" branches may be left to keep the "mother" plant alive. They can be removed as the new plant grows. When the new camellia graft is growing well, the new plant is cut off below where it is attached to the mother plant which leaves just the new graft. The potted plant may be removed to a new location.
Stem grafting follows the same principles as branch grafting except stems or small branches are grafted together. In this case the bark is scrapped off both plants exposing the white layer and the green cambium layer. The mother plant stem is scrapped about 40% of its diameter but the potted plant only 10%. The two stems are joined together edge-to-edge (cambium layer to cambium layer) approximately 4"-6" and then taped together. I have used both electrical adhesive tape and plastic (non-adhesive green) plant tape that comes on a roll. If needed, wire plant ties may be used to gently bend or shape the branches to meet correctly. Each pot is secured with a vertical stake or bricks to keep the pot securely in place. Wind, animals, children or even a gardener misstep have been known to disrupt the potted plant. These grafts do not need to be covered and may not grow if covered. The plastic non-adhesive tape is easier to remove without disrupting the callus or breaking the top off the new stems. The adhesive electrical tape is easier to place the stems together.
This grafting approach is appealing for a number of reasons. Primarily, it maintains the "mother" plant in the landscape while providing an opportunity to add new varieties. It is possible to have multiple varieties on one plant. It is a "fail safe" way to improve the quality of your collection. It may also be used to introduce virus to a non virus plant or to improve the quality and quality of virus in a camellia. For example Frank Houser is an excellent red camellia reticulata which is not always available in its variegated form-- red with white blotches. A variegated camellia (e.g. Adolph Audusson variegated) can be stem grafted to the non variegated camellia (Frank Houser in the above illustration). This process will transfer the virus to the non virus plant when the plant breaks dormancy and the "sap" flows up the plant. This may be tracked by examining the leaves. The virus also infects some leaves with yellow lines or blotches.
AIR LAYERING: A good sized plant can be provided in one year with air layering. While it may be done anytime of the year, spring is best because the plant is beginning to grow. The rooting medium is the air rather than soil.
A healthy straight limb is selected on the camellia being propagated. Measuring back from the tip 12 to 18 inches remove a ring of bark including the cambium layer (green). The bark is stripped with a knife 1.5 to 2 inches the full diameter of the branch.
This ringer area is covered with a full handful of presoaked sphagnum moss. The simplest way is to soak the moss for an hour in a bucket then by hand squeeze out the excess water. Medium weight plastic is wrapped tightly around the moss and secured with twist ties. The whole ball is covered with aluminum foil and also secured with ties.
If started in the spring, roots are usually formed by the fall. The aluminum foil is removed. The roots can be seen through the clear plastic. When there are sufficient roots to sustain the new plant, the limb is cut from the "mother" plant. The plastic is then removed. The sphagnum moss is retained to help protect the tender roots. The new plant is planted in a one gallon pot filled with half sand and half camellia/azalea mix or coarse pear moss. A loose mix rich in humus is optimal for root development and growth of a healthy camellia.