The California blueberry industry has experienced substantial growth over the past decade. During this period, many growers have learned that blueberry production is often challenging.

Blueberry, Vaccinium corymbosum is an ericaceous (member of the heath family), acid soil loving plant.

It is characterized by a very narrow range of environmental adaptation. Within this range, blueberry is capable of quite exuberant growth and production. Where soil and irrigation water and other environmental conditions lie outside this narrow range of adaptation, commercial blueberry growers must modify soil chemistry, soil physical properties and irrigation water chemistry. Modifications are necessary to insure the continued production of high yielding plantings of quality fruit.

Despite a grower’s best efforts, blueberry plantings can display moderate to severe leaf chlorosis, which often inhibits optimum production. Such plants usually suffer from stunting or lack of vigor. Production of fruit-wood is limited. Even flowering can be reduced.

When confronted with such problems, the grower should recognize that “iron chlorosis” is often not the specific problem. The plants are often not precisely deficient in iron. The term “iron chlorosis,” as used in the context of blueberry culture, is something of a misnomer. The normal range for iron concentration in blueberry leaf tissue is: 80 – 200 ppm Fe. Chlorotic blueberry leaf tissue can often have leaf iron concentrations that are equal to or even higher than the tissue levels found in green blueberry leaves. Thus, it is important to determine the precise cause of the chlorosis. Think of the presence of visual chlorosis symptoms as a “stress indicator” for the blueberry plant. The fall and winter period is an opportune time to address these problems, since root zone changes are not desirable during the flowering, fruit set and harvest periods of the year.