Posted by: Curtis Utley, Jefferson County Extension
One of the most fantastic horticultural tools discovered by man has to be the art of grafting. The ability to attach a piece of one tree to the branch of another is nothing short of magic. Detached scion grafting was discovered sometime during the first millennium B.C. and contributed to the movement of woody tree fruits out of Asia and into Europe along the silk road (Mudge, K. et al 2009). For Centuries now mankind has been able to perpetuate superior clones of tree fruits by removing a twig or bud from a superior mother plant and attach that twig or bud to a seedling of the same tree species. The result is a replicate of the mother tree growing on the root system of a seedling tree of unknown fruit quality.
|Macintosh branch grafted onto Crabapple|
|Hybrid Tea Rose|
|Chip bud grafting|
Other advantages of grafting include size manipulation, avoidance of juvenility, disease and abiotic stress resistance, damage repair, and the creation of unnatural growth forms. Orchardists and home hobbyists alike have found dwarf fruit trees advantageous. Producing full size fruit on a small tree allows an orchardist the opportunity to plant multiple varieties in the same space it would take to grow one full size fruit tree. Dwarf fruit trees are also much easier to manage and pick than full size trees. Many fruit bearing trees grown from a seed will not begin bearing fruit until they are mature this is called juvenility. Grafting mature wood onto a seedling tree overcomes this natural habit and allows for fruit production a few years after grafting instead of 15 or more years for a seedling tree to come into bearing.
|Production orchard dwarf apple|
Starting in the Twentieth Century research scientists began actively selecting under stalk of horticulturally important crops for resistance against, disease, insect pests, drought, and soil issues allowing these crops to be grown more widely. Even annual crops such as tomatoes and watermelons have been grafted onto hearty rootstocks that have been selected for resistance against soil borne pathogens and greater production.
|Dwarf limber pine|
Grafting also allows horticulturists to produce unique unnatural ornamental growth forms, think of weeping mulberries, weeping cherries, tree form roses, and bonsai conifers. The last reason for grafting I’ll mention is a technique called inarching. Inarching is a rescue operation orchardists use to save trees that have been girdled by rodents or attacked by a root fungus. New resistant root stock trees are planted directly beside the suffering orchard tree the top of the small rootstock tree is cut off, whittled into a chisel point and inserted (by bending the stem) into a slot cut into the trunk of the suffering tree. When the graft union takes the new rootstock serves as a bridge across the damaged lower trunk or disease ridden root system.
|Whip graft budding strip|
|Successful whip graft union|
If you are interested in learning how to graft woody plants I will be teaching a hands-on grafting workshop open to the public on March 31. The workshop will be held at the Jefferson County Extension office located at the Jefferson County Fairgrounds. Participants will be producing their own grafted apple tree to take home and plant. Dwarfing rootstock and a variety of apple cultivars to select from will be provided to participants. This workshop will be repeated April 1 and again on April 2. This workshop costs $20.00 per person, space is limited and reservations are required.
Register at: http://jeffcohort.eventbrite.com
The Jefferson County fairgrounds are located at: 15200 West 6th Ave., Golden, CO 80401
Citation: Mudge, K. et al. 2009; A History of Grafting. Horticultural Reviews, Vol. 35; John Wiley &Sons, Inc.