Nutrient deficiencies of perennials: Part 7 of 12

Shrub verbena (Lantana hybrida)

Shrub verbena (Lantana hybrida) is a semi-woody shrub hardy in USDA Hardiness Zones 8-11. It can be used as a containerized ornamental, hedge or groundcover. Lantana performs best in well-drained, slightly acidic soils and full-sun conditions. It is sensitive to insect pests such as mites and whiteflies.

Fertilizer recommendations for greenhouse culture suggest 125-150 parts per million nitrogen for constant liquid fertilzation or weekly applications of nitrogen at 175-200 ppm. Even at a moderate fertility level, nutrient deficiencies can occur during production, the symptoms of which have been reported as chlorosis of the lower leaves.

Fertility management

Fertility monitoring and management for Lantana requires a balancing of the plant’s needs. Growers must be aware and manage the root substrate pH and electrical conductivity and provide adequate, but not excessive, levels of all essential elements. Using a plant diagnostic laboratory to identify the source of problems is still the best way to ensure accurate diagnoses, since many nutritional, physiological, insect and disease problems can mimic each other.

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Nutrient-deficiency descriptions are unavailable for most perennials, yet growers must often make quick diagnoses. A research project initiated at the University of Florida in Milton documented deficiency symptoms in vegetatively propagated Lantana ‘Athens Rose.’

Pictures related to the nutrient deficiencies series may accessed by viewing the PDF files of the pages that originally appeared in GMPRO magazine: Page 1. Page 2. Page 3. Page 4. Page 5. Page 6. Page 7. Page 8.

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Nitrogen (N)

Nitrogen-deficient plants are smaller in size with less lateral shoot growth.

The youngest leaves of nitrogen-deficient plants are narrower than the control. Young leaves are smaller and more rounded than healthy ones.

At the advanced stage, oldest leaves are uniformly dull yellow with a faint red pigmentation on the tip and base. 

Phosphorus (P)

Phosphorus-deficient plants have darker-green foliage and shorter internodes than the control.

The oldest leaves express a dull-green cast with irregular purple patches between the veins.

Under advanced symptoms, the upper leaves appear darker and begin to roll inwards at the margins. Flowering is limited.

Potassium (K)

Potassium deficiency begins on the recently mature leaves as a marginal chlorosis.

Potassium-deficient plants then express a dull-greenish-yellow chlorosis toward the midvein.

Finally, a reddish-brown necrosis develops on the midveins of the leaf tips. Upper leaves turn dark green and are smaller in size compared to healthy leaves.

Calcium (Ca)

Calcium-deficient young and youngest leaves are narrow.

The youngest leaves turn whitish-green. The young leaves become deformed and curl downward.

The young leaves become glossy, express an interveinal chlorosis and cup downwards while the youngest leaves develop faint necrotic spots.

Magnesium (Mg)

Magnesium deficiency begins on the recently mature leaves as marginal chlorosis. The young leaves are dull olive-green.

As symptoms progress, a uniform greenish-yellow chlorosis appears over the young and youngest leaves. 

At the advanced stage, mature leaves express a faint interveinal chlorosis that is more defined on the margins.

Sulfur (S)

Sulfur-deficient leaves are smaller with a greenish-yellow tone, when compared to the control.

As symptoms progress, a yellowish-green chlorosis appears on the youngest and young leaves. A thin band of chlorosis forms on the margins of recently mature leaves.

A bright-yellow chlorosis forms on the stiff and rigid young and youngest leaves. Irregular patches of green tissue remain on the recently mature leaves.

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Boron (B)

Boron-deficient plants initially express darker-green foliage and shorter internodes when compared to the control.

Boron-deficiency symptoms are also observed on the axillary shoots as deformed necrotic buds.

At the advanced stage, deformed youngest and brittle young leaves have chlorotic margins.

Copper (Cu)

Copper-deficient plants express dull-green young leaves and bluish-green mature foliage.

Copper-deficiency symptoms are also observed in the axillary shoots as spindly flower stems with malformed florets.

At the advanced stage, the young and youngest leaves turn yellow from the leaf base to the tip.

Iron (Fe)

Iron-deficient plants first express pale-green young and youngest leaves The recently mature leaves develop a basal chlorosis.

Symptoms progress rapidly and a yellowish-green chlorosis develops on the shoots and recently matured leaves. Yellowish-white chlorosis forms on the young and youngest leaf margins.

A well defined interveinal chlorosis is expressed on young tissue as reddish-brown necrotic patches form along leaf margins.

Manganese (Mn)

Manganese deficiency begins on the young leaf bases as a faint olive-green chlorosis. The youngest leaves are narrow and pale green.

The chlorosis spreads rapidly across the leaf blades of young leaves, while a band of greenish-yellow chlorosis forms on the recently mature leaf margins.

As symptoms progress, the recently mature leaves express a distinct interveinal chlorosis.

Zinc (Zn)

Shoot growth on zinc-deficient plants is spindly, thick and dull green.

As symptoms progress, the young shoots develop a rosettelike habit with straplike leaves. The dull-green chlorosis turns yellow-green. Recently mature leaves express veinal chlorosis.

Under advanced deficiency conditions, plants are extremely brittle with bright-yellow chlorosis on young and recently mature leaf margins. Leaf tips curl downward.

- James L. Gibson, Kathryn Campbell, Sharon Wombles and Jude Groninger

James Gibson is assistant professor, Jude Groninger is senior laboratory technician, and Sharon Wombles and Kathryn Campbell are former undergraduate research assistants, University of Florida, Institute of Food and Agricultural Sciences, West Florida Research and Education Center, (850) 983-5216, Ext. 103; jlgibson@ifas.ufl.edu .

The authors thank the Fred C. Gloeckner Foundation for grant support, Smithers-Oasis for the propagation medium, Emerald Coast Growers  for plant material and Quality Analytical Laboratories for tissue analysis.

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