The process of “making” a fruit tree refers to propagation, the act of creating a new plant. This practice is necessary to preserve the specific, desirable traits of a chosen fruit variety. Propagation methods ensure the new tree will produce the same quality of fruit as the parent plant.
Growing a Fruit Tree from Seed
Starting a fruit tree from seed is the simplest method, though it carries significant genetic uncertainty. Most cultivated fruit varieties, such as apples and pears, are highly heterozygous, meaning the resulting seedling will not be “true to type” and will produce fruit different from the parent. This genetic variation makes seed propagation primarily useful for creating new rootstocks or for breeding experiments, rather than reliably reproducing a favorite fruit.
The primary obstacle to germination is a built-in dormancy mechanism that must be overcome. This is achieved through stratification, which simulates the natural cold and moist conditions of winter. Seeds are mixed with a sterile, moist medium like vermiculite or sand and kept at 34 to 40 degrees Fahrenheit for a specified period, often 60 to 90 days. If the seeds have a hard outer shell, they may also require scarification—physically weakening the seed coat to allow water penetration—before stratification. Seed-grown trees also take significantly longer to reach fruiting maturity, often adding several years compared to propagated trees.
Starting Trees Using Cuttings
Propagation by cuttings is a form of asexual reproduction, or cloning, that guarantees the resulting tree will be genetically identical to the source plant. This technique involves taking a piece of stem, leaf, or root and encouraging it to develop into a complete, independent plant. The resulting tree grows entirely from the single piece of wood, eliminating the genetic lottery associated with seeds.
There are two main types of stem cuttings: softwood and hardwood. Softwood cuttings are taken from new, flexible growth during the active summer growing season. Hardwood cuttings use mature, dormant wood taken in late fall or winter.
Applying a rooting hormone stimulates root development before cuttings are placed in a sterile, well-aerated medium, such as a mix of sand and perlite. Success rates vary widely; some species, like figs, root easily, while others, like most apple and pear varieties, are difficult.
Mastering the Technique of Grafting
Grafting is the most widely used method for creating a high-quality fruit tree, combining the desired fruit-producing variety with a root system. The technique involves physically joining two separate plant pieces so they grow as one: the scion (the desired cultivar shoot) and the rootstock (which provides the root system). This method ensures the fruit is true to the parent variety while allowing control over tree size, soil adaptation, and disease resistance, traits determined by the rootstock.
The success of any graft depends on the alignment and fusion of the cambium layers of the scion and the rootstock. The cambium is a thin layer of actively dividing cells beneath the bark, responsible for producing new vascular tissue. Intimate contact between these layers must be maintained to form a continuous vascular connection, allowing water and nutrients to flow between the components.
Grafting is best performed in late winter or early spring while both the rootstock and scion wood are still dormant but just before the rootstock’s buds begin to swell. The rising sap flow promotes healing. Techniques like the Whip and Tongue graft or the Cleft graft are common, requiring precise cuts to maximize the surface area and lock the pieces together.
Whip and Tongue Graft
The Whip and Tongue graft is used when the scion and rootstock are of similar diameter, typically less than one inch. This method involves making long, sloping cuts on both pieces, followed by a secondary “tongue” cut. This creates an interlocking joint that holds the pieces securely and increases the length of cambial contact. Once joined, the union must be tightly bound with grafting tape or wax to prevent desiccation while the callus bridge forms.
Cleft Graft
The Cleft graft is used on thicker rootstocks. The dormant scion is tapered into a wedge and inserted into a split made in the top of the rootstock. This ensures the cambium layers align along at least one edge.
Initial Care for Newly Propagated Trees
Once propagation is successful, the young tree requires focused attention to establish itself. The immediate goal is to protect the tender new growth from environmental stress, a process called hardening off. This involves gradually exposing the plant to outdoor conditions to prevent shock as it adjusts to its permanent location.
Managing the growth of the young tree is particularly important for grafted plants. Any new shoot growth appearing below the graft union, known as a sucker, must be removed immediately. These suckers originate from the rootstock and, if left unchecked, will divert the tree’s energy away from the desired fruiting wood of the scion, potentially causing the rootstock to dominate and eventually kill the grafted portion.
Suckers should be cut cleanly and as close to their point of origin as possible, avoiding leaving a stub that could resprout. A consistent watering regime is needed, especially in the first year, to support the development of a strong root system. Once the sapling has developed a robust root ball, it can be safely moved from its temporary pot or nursery bed to its final planting site.