Grafting Avocado Trees

Question from Melody:
I am writing to get some information on grafting fruit trees. We have 5 or 6 old avocado trees that don’t produce fruit and I am thinking maybe grafting would work to have them bare fruit again. If this is in fact a way to restore old trees, we are looking to find someone who could graft a couple of them. We live in La Habra Height, (near La Habra which is about 20 minutes from Anaheim-Disneyland area) Do you know of anyone who could do this in our area?

Answer from Pat:
When an avocado tree does not bear fruit the problem sometimes is that it was grown from a seed and was not a good tree in the beginning. In this case an expert can graft the stump with a good bearing variety. If you do not know if the tree was from a seed or not then I would recommend you begin by feeding the tree. Old trees that do not bear fruit may be starved for nutrition, especially nitrogen. Avocado trees are heavy feeders and need 2 full pounds of “actual nitrogen” per year. (See my book for explanation of “actual nitrogen” and also a discussion of organic fertilizing of avocados.) Basically if you fertilize your trees with 16-16-16 formula that means that particular fertilizer contains 16 percent nitrogen so you will need to give roughly 12 pounds of 16-16-16 fertilizer each year to a mature tree. Begin fertilizing in February. If your trees have not been fed enough or not for a long time you can give half the amount (6 pounds of fertilizer) sprinkled all over the ground under the tree in February and divide the amount up and feed once every month for two or three more months. When the trees are growing in good rich organic soil and when they are fed organically they will not need quite as much actual nitrogen since the soil itself will create nitrogen. Full explanations are in the February chapter of my book.

Sprinkle the fertilizer all over the ground under the tree from a foot or two from the trunk to the branch tips then water in to the ground thoroughly with water from the hose or sprinklers.

Wet and waterlogged soil will also cause avocados to fail to bear fruit. Avocado trees need good drainage and without it they will not bear fruit.

Also, prune out any dead, dying or rotted wood inside the tree, but otherwise do not prune since you may cut off good fruiting wood or cause sunburn to the trunk and branches. NEVER dig or cultivate under the tree but mulch the ground and allow all those big leaves to lie on the ground under the tree just where they fall. I know it looks messy but this is the right way to care for avocado trees if you want fruit. Cultivating under an avocado will cause all fruit to fall off. If you have cultivated or dug up the ground under the tree or in any way disturbed the roots that are spread out on top of the ground under the tree this also can prevent fruiting for a year or two until the roots recover.

Begin fertilizing and mulching now to get the trees going again and try this program next year and if this does not work then my recommendation is to attend a meeting of the Rare Fruit Growers in your neighborhood and see if they know of anyone to do the grafting. The type of grafting you might need is called “top work”. Your local University Extension Home Horticulture or Agricultural Advisor may also be able to locate a grafting specialist in your area.