Have you ever seen multiple trunks coming out of the ground from a lemon tree? I inherited this lemon tree and one of the trunks seem slightly smaller in size. Upon closer examination its coloration was slightly different; it had thorns, and its fruit was entirely different than the rest of the tree. I picked one of the fruits it was huge; it looked like a grapefruit! Its insides were similar to a grapefruit. It had thick rind and very little meat. It was definitely something I would not eat.
I concluded that the lemon tree had been grafted onto a grapefruit type root. They sprout from the root system had become a separate distinct tree expressing the traits of the grapefruit rootstock. Evidently the previous owner had covered up the grafted section of the trunk and let the sprout grow and grow and grow until it was fifteen feet high.
According to “A History of Grafting” K. Mudge et al.,” The domestication of woody species that do not root easily from cuttings, such as apples, pears, and plums, did not come until the discovery of grafting…about the of the first millennium BCE.
Why graft? Grafting combines the best of both worlds. A strong and vigorous root system from one woody plant with a desirable tree fruit or flowers of another compatible woody plant. Grafting can be described as the deliberate joining of fusing of plant parts on to another. Grafts can be made directly to the rootstock to a cut shoot of the desired plant (scion) to form a single plant. This type of grafting aligns the shoot (scion) with the rootstock. A similar size cutting is aligned with a corresponding diagonal cut on the top of the rootstock. The cuts are aligned and bound together. The graft union usually appears as a swollen point or a bulge usually in the lower point of the trunk. Some trees like flowering cherries may be grafted as high as 3' to 4' above the rootstock.
Other grafts may involve several (scions) shoots off of a single rootstock resulting in different species of fruits growing on a single tree. How is this possible? Watch this video from Dave Wilson Nursery www.davewilson.com “How to Graft a Fruit Tree.” A video showing multiple bark grafts on a nectarine tree. Multiple grafted trees are ideal for gardeners with limited space who do not need large yields, but like different species of pears, apples, nectarines, etc. Imagine, One tree with four varieties!
As described above the rootstock a single grafted tree still active. Below the graft, the growth might appear. These are called suckers. Allowed to grow they can deprive nutrients to the desired parts of the tree. Be vigilant and cut off suckers as they appear.
For further investigation and reading:
“Citrus Problems – Sprouting Rootstock”, Dan Gill LSU AgCen, https:www.lsuagctr.com/MCMS/Relatedfiles PDF
Dave Wilson Nursery: www.davewilson.com
“Growing fruit trees from seed won't yield the fruit you expect”, Maureen Gilmer, Howard Scripps Howard News Service, July 28, 2013, https://siouxcityjournal.com/lifestyles/home-and-gardening/
“A History of Grafting-Horticulture and Landscape Architecture”, K. Mudge, J. Janick et al, www.hort.purdue.edu>newscrop.janick-paper pdf