March arrived last week with typical March weather; snow, rain, sleet, some sun and windy. The days are longer and many people are eager to get out and do something horticultural! This is a good time to cut some scions for grafting later in April. If you have an apple or pear tree that produces tasty fruit, you can graft it onto another tree of the same species. Even old wild apple trees can be grafted onto or from, if the fruit is tasty! If your apple tree does not produce fruit reliably every year, you can graft crabapple branches into it. Crabapple trees generally flower more profusely than the eating varieties and their pollen is suitable for fertilizing most other apple varieties.
Intentional grafting is one of the oldest horticultural practices known to man. It dates back thousands of years and was widely practiced during the Roman Empire and most likely predates that time as well. Generally speaking, it is a technique for joining two different plants in such a way that they can grow together as one plant. Grafting is also sometimes used to reunite the same plant when the plant has been damaged. For example, an apple tree that has been girdled by rodents can sometimes be saved by creating “bridge grafts” that connect the roots to the trunk again bypassing damaged tissue. Small-diameter branches from the top of the tree are grafted onto the trunk, both below and above the damaged tissue, creating a “bridge” to bypass the damage.
Most of us see examples of grafting every day, if we live in a community that has street trees. Street trees of all species are usually grafted in the nursery where they are produced. We also eat fruit from trees daily which are the result of a transplant. Almost all of our apples and most other fruit trees are produced by grafting.
The process is really very simple. It is a way to connect the plumbing from one plant to the plumbing from another plant by properly aligning the pipes. Plant plumbing consists of tubes or containers that look like vertically connected straws. Xylem vessels are the water connection pipes and phloem vessels are the
food connecting straws. Between the pipes (vessels) are cells and tissues that can regenerate new pipes and enable fusion. For a transplant to be successful, the two different plants usually need to be quite close together. Apples easily graft onto other apples and pears easily graft onto other pears, but apples and pears do not graft onto each other well. Sometimes the transplant partners do not really look alike and are not always very close. Pears are often grafted onto quince roots and lilacs are often grafted onto privet roots (a common hedge plant).
There are many reasons for grafting ranging from economical to purely aesthetic. Street trees are grafted to ensure a nice straight trunk that you can walk along without the side branches hitting you in the face. Grafting a bud onto an existing trunk on top of a well-developed root system ensures that the shoot from this bud will grow quickly and for a long time. Typically, a bud of the desired cultivar is grafted onto the trunk just above the root system during the dormant season. When growth begins and the bud begins to sprout, the top remaining part of the tree is removed so that all the energy, water and nutrients that the root system is able to produce are funneled into this single stem of the tree. bud. The other shoots that may come from the roots or the trunk are removed so as not to compete with the desired one.
In the wild, an apple tree may take many years to bear fruit while growing on its own roots, but you can graft a mature branch of a different variety onto that tree when that tree is young and have it produce fruit in one one time. year. There are over 2,000 different named apple tree cultivars and hundreds of different rootstocks they can be grafted onto. Grafting not only represents the characteristics of the scion, i.e. the part that is attached, but is also influenced by the characteristics of the plant to which it is attached (the stump). Some apple tree rootstocks limit the height of the tree to 6 feet or less, regardless of the variety grafted onto it. Other rootstocks can tolerate adverse conditions such as excess moisture or drought. Others can bestow resistance to disease, anchoring ability in the wind, and other traits.
Next week I will enter the transplant process.