Home Gardening

Missing nutrients cause plant problems
The Coast Gardener Newspaper and Web Column - July 20, 2002

Sometimes, plant problems are misdiagnosed when nutrient deficiencies are overlooked or the characteristics of such deficiencies are not understood. Many people automatically blame insects or biotic diseases (those caused by bacteria, fungi, or other living things) as the problem.

A gardenia showing iron chlorosis

Troubleshooting nutrient deficiencies can be a lot easier if you know what signs to look for. The following information describes signs of nutrient deficiencies in woody plants. For example, have you ever noticed your gardenia's foliage turn yellow except for the leaf veins? This is called iron chlorosis. The pH of your soil is too high and iron is unable to be utilized by the plant. This is a common problem in highly alkaline soils.

Nitrogen (N) deficiency shows a general yellowish-green coloration on the foliage. Usually, older leaves are affected the most. Growth will be stunted with fewer leaflets. Leaves my drop prematurely before the dormant season. Veins, petioles, or lower leaf surfaces may become reddish-purple, especially while they are young.

Potassium (K) deficiency exhibits partial chlorosis (yellowing) of the most recently matured leaves in between the leaf veins. This chlorosis begins at the leaf tips. Older leaves may turn brown and curl downward.

A deficiency of calcium (Ca) causes death of terminal buds, tip die-back, and chlorosis of young leaves. Leaves may also become hard and stiff. The lack of calcium can look like the affected woody plant has a root problem.

A plant lacking magnesium (Mg) shows marginal (on the edges) chlorosis on older leaves followed by interveinal (between the veins) chlorosis. Leaf margins (edges) may become brittle and curl upward.

A sulfur (S) deficiency exhibits uniform chlorosis of new leaves while older leaves are usually not affected.

As mentioned with the gardenia example, plants lacking iron (Fe) appear to have interveinal chlorosis of young leaves (sharp distinction between green veins and yellow tissue between veins).

Manganese (Mn) deficiency also shows up as interveinal chlorosis of young leaves beginning at margins and progressing toward midribs. Necrotic (dead) spots are also evident on the leaves.

When boron (B) is deficient, terminal growth, or the ends of the branches, dies and new growth that does occur has sparse foliage. Young leaves may be red, bronzed, or scorched. Leaves may be small, thick, distorted, or brittle.

Copper (Cn) deficiency also causes terminal growth to die. Leaf symptoms are not usually pronounced, but the veins may be lighter green than the leaves.

When Molybdenum (Mo) is not present in sufficient amounts, the older leaves appear "cupped" and marginal leaf chlorosis is followed by interveinal chlorosis.

It is always best to perform a soil test every three years to determine which nutrients, if any, are lacking in your soil. If nothing else seems to explain your plant's problem, ask the question, "Could my problem be a nutrient deficiency?"

In other news, please plan on attending an informative program entitled "Landscaping with Wildflowers" on Wednesday, July 24 at 1:00 p.m. at the Orange Grove/Lyman Community Center in Gulfport.

The featured speaker is Bob Brzuszek, Senior Curator with the Crosby Arboretum in Picayune. Liz Cox with the Natural Resources Conservation Service is also slated to speak.

The Harrison County Soil and Water Conservation District Auxiliary and the Natural Resources Conservation Service is sponsoring the event. Native wildflower seed packets will be distributed to all who are eager to start their own wildflower plot. Have a wildflower you want identified? Bring it with you! Make plans now to attend this informative session.

These archived gardening columns were written by Chance McDavid, former Harrison County Extension Agent.