UF/IFAS Okeechobee County Extension Service

458 Highway 98 North

Okeechobee, FL 34972-2578

Phone: (863) 763-6469

E- mail: dfculbert@ifas.ufl.edu

November 5, 2003

Feature Article - for release the week of November 9, 2003

Dan Culbert - Extension Horticulture Agent

Our Okeechobee Master Gardener class is winding down, and last week our volunteers were tromping through citrus groves. Not only are they learning about the ways to fertilize dooryard orange trees and deal with grapefruit pests, they were also shown the importance of what we often can’t see: the roots.

Citrus trees worth growing are a combination of two different plants that have been forced to grow together. In the nursery, a bud of that delicious juicy fruit is slipped into a T-shaped cut on a seedling tree. This combination of root and top produces a tree that will stand up to our local soils and often gives the plant vigor and pest resistance as well.

Citrus researchers have found that certain kinds of citrus plants can withstand certain conditions better than others. Besides the kind of fruit you want on your table, the choice of rootstock it critical for successful dooryard citrus production.

Soil moisture tolerance, cold hardiness, variety interactions and pest resistance should be considered when making a rootstock choice. According to our local Citrus Extension agent Jack Hebb, Smooth flat Seville (a.k.a. Australian sour) and Cleopatra mandarin are among the best choices for local rootstocks.

Because local soils are more like the coastal regions than the interior Highlands areas of Florida, Okeechobee’s commercial citrus is considered part of the Indian River citrus growing region. Citrus planed in our area is placed on poorly drained soils that are subject to flooding.

Half of the commercial groves in our area are planted to Sour Orange rootstocks, while the old time rootstock used in the Highlands region was the Rough lemon. Sour Orange is very susceptible to a virus disease known as Quick decline, which rapidly kills the tree. Rough lemon does not handle freezes well. Newer groves are trying Swingle citrumelo and Carizzo citrange with mixed results.

Bargain citrus trees are often excess plants that were destined for the groves, but for one reason or another, were not used there. Some may have been recycled back to the nursery to be grown out to look pretty for dooryard fruit tree customers, then shipped to areas of the state where the roots may not be well adapted.

Homeowners looking for a dooryard citrus tree may object to the high cost of a citrus tree from a reputable nursery. Locally, I have seen few nurseries that carry the right rootstocks for our area. Prospective buyers may be tempted to just give up, and go for the kind of fruit, and ignore the roots. And, if the nursery sales staff can not tell you the kind of rootstock - or doesn’t know what a rootstock is - hold on to you wallet and run as fast as you can to another garden center.

If the wrong choice of rootstock is made, realize that the tree will take five or more years to produce its first crop, and after this wait, it may not be prolific or of the highest quality. The owner may try to overcome a poor rootstock by over-applying fertilizers or pesticides, but often will not be satisfied with the results.

I’d suspect that most persons in the market for dooryard citrus trees are retirees that have moved to this area. They want their fruit, and they want it now. Mistakes made in rootstock selection because of a penny-wise decision may cost several years of time, time that retirees may not be able to afford.

So here’s the bottom line: if you want high quality dooryard citrus, keep looking and asking until you find the right combination for both you table and your dooryard conditions.

If you need additional information on dooryard citrus and proper rootstocks, call or stop by our office at 458 Hwy 98 North in Okeechobee. Our website is http://okeechobee.ifas.ufl.edu and our phone number is 863-763-6469, and you can email us at okeechobee@ifas.ufl.edu.

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Bowman, Kim D. Citrus Rootstocks: The Foundation of a Tree (website) Fort Pierce: USDA ARS Horticultural Research Station. http://www.ars-grin.gov/ars/SoAtlantic/fp/hb/bowman/citrus.html

Castle, Bill & Tucker,  David.  Florida Citrus Rootstock Selection Guide (SP-248).  Gainesville: UF/IFAS Extension Service, 1993.  For sale at: UF/IFAS Bookstore.

Castle, Bill et.al.  Rootstocks for Florida Citrus, 2nd Ed. (SP-42)  Gainesville: UF/IFAS Extension Service, September 1993.  Check for availability at: UF/IFAS Bookstore.

Ferguson, James J. Your Florida Dooryard Citrus Guide - Selecting A Citrus Tree for Your Climate. (HS-885) Gainesville: UF/IFAS Extension Service, August, 2002. http://edis.ifas.ufl.edu/HS117

Ferguson, James J. Appendix B. Rootstock Characteristics in Your Florida Dooryard Citrus Guide - Appendices, Definitions and Glossary (HS-891). Gainesville: UF/IFAS Extension Service, August, 2002. http://edis.ifas.ufl.edu/HS123

Stover, Ed, Castle, Bill, and Hebb, Jack. Citrus Rootstock Usage in the Indian River Region HS-852) Gainesville: UF/IFAS Extension Service, April 2002. http://edis.ifas.ufl.edu/HS129

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