Citrus Orchard Topworking

Brokaw Nursery provides citrus topworking service for mature trees for commercial growers. Some growers prefer this method of propagation, especially when they want to convert healthy orchards of oranges, grapefruits, or mandarins to another variety or species of citrus. It is especially appropriate for converting to Eureka lemons as sieve tube necrosis and bud union incompatibility may be minimized if the original rootstock is a citrange, citrumelo, or other variety that is incompatible with Eurekas. Eureka buds seem compatible with the common citrus fruiting varieties.

The grower should use this alternative only if he is confident of the basic health and longevity of his already established trees. Also, he should not expect that the process will be cheap. In addition to substantial grafting fees he will be liable for grove preparation, brush disposal, and general maintenance.

The Process

In late spring, some one or two months after tree preparation, the grafting (budding) is done. After whiting is applied to the trunk and main limbs of the tree, the budder inserts and wraps, one to three buds into each of three or four main branches approximately one or two feet above the points to branch emergence from the trunk.

Buds are unwrapped about a month later, and all branches except for a nurse limb are removed about eight inches above the inserted buds. The scions are allowed to grow for a time, are pruned for strengthening, and will create the new tree canopy.

The following year, nurse limbs are removed. After two years, the 8" stubs are removed from above the budding locations.

Typically, the first budding does not produce a full stand of growing buds. Therefore, rebudding is accomplished before the first lopping of budded limbs and often entails two or more loppings of budded limbs depending on when they were successfully budded.

Responsibility of the Orcahrd Manager

In general, the owner/manager is responsible for tree preparation, clean-up and brush removal, normal maintenance of the orchard, and final tree forming. Typical specific tasks are the following:

  1. Pest control: strict control of snails, ants, aphids, and other damaging insects.
  2. Tree preparation: Some two months before grafting, the interior of the canopy is to be completely pruned (except for a nurse limb) to a height of six feet or more and scaffolding thinned to no more than three or four main branches and a nurse limb. The nurse limb is ideally a lower branch which will be left to serve for a year or more. If no lower branch is available one of the three or four remaining main branches will serve. These interior limbs must be maintained free of sprouts before and after grafting.
  3. Whitewash: Prior to grafting, substantial fortified whitewash, or water based white paint, should be applied to budded branches from ground level to a point above bud insertion locations.
  4. After tape removal and girdling by the grafter, all successfully budded branches except the nurse limb are to be lopped off completely, eight inches above the point of bud insertion, and brush moved out of the way. The nurse limb must not be removed.
  5. Brush must be removed from the orchard floor.
  6. Nurse limbs should be removed after one or two years.
  7. Two years after grafting, stub branches from above the buds are to be removed with a slant cut and properly treated.
  8. Care needs to be used in irrigation practice as the amount of foliage borne by the tree will vary greatly during the process.
CAUTION - Orchard manager should not remove tape or sprouts from any trees without prior consultation with the grafter.

Responsibility of the Grafter

In general, the grafter consults with owner/manager, procures suitable budwood, grafts the trees, and follows up once or twice for regrafting. Typical specific tasks are the following:

  1. Consult with owner/manager and approve tree preparation.
  2. Graft the trees in late spring, usually May or June.
  3. Manage regrowth. Sprouts must be removed, and regrowth removed, except for the few that emerge from the ends of the grafted and lopped branches. These that emerge at the branch ends, above the points of bud insertion, should be pruned back to a length of one inch or less. It is important to leave this stunted growth as it maintains life in the otherwise unfunctional stub.
  4. Girdle above grafts, as required, and remove tape.
  5. Prune. Bud shoots should be allowed to grow to lengths of some 15"and then pruned back to 8"-9" for strengthening. As secondary shoots elongate to 12"-15" they, too, should be shortened to 8"-9".
  6. Regraft as necessary, girdle, and remove tape.

Charges by the Grafter

Total per tree Quoted per project
At signing of contract 25%
After completion of budding 50%
After one year 25%

Grafter is not responsible for acts of God such as frost, wind, flood, or any other event over which he has no reasonable control.