Nutrient deficiencies of perennials: Part 8 of 12

Veronica x ‘Goodness Grows’

Veronica x ‘Goodness Grows’ was discovered at Goodness Grows Nursery, in Crawford , Ga., and has become one of the most popular veronica varieties. University of Georgia horticulture professor Allan Armitage said the selection is probably a hybrid between V. alpina ‘Alba’ and V. spicata. Plants have a low-growing habit and produce long flower racemes for most of the summer. ‘Goodness Grows’ does best in USDA Hardiness Zones 3-8.

Production of ‘Goodness Grows’ is relatively easy. Michigan State University researchers found it to be day-neutral in regards to photoperiod; however, vernalization (cold treatment) is required for flowering.

Fertilizer needs

Recent research at Virginia Tech University on fertilizer requirements of ‘Goodness Grows’ found fastest growth and highest quality with moderate to higher levels of fertility obtained by maintaining electrical conductivity levels at 3.0 miliSiemens/centimeter (PourThru method).

The best way to ensure proper nutrient levels is to test the root-zone pH and electrical conductivity regularly. If deficiency symptoms appear, verify the diagnosis by sending foliar samples to an analytical laboratory.

Virginia Tech researchers induced and documented deficiency symptoms in vegetatively propagated Veronica x ‘Goodness Grows.’ We used a hydroponics system to completely exclude the desired element. This also afforded a great view of the root system.

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It took a relatively long time to induce incipient deficiency symptoms. For some elements, what we judged to be advanced symptoms had yet to appear when the research study was terminated after 90 days.

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.

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Nitrogen (N)

Initial symptoms include slight chlorosis (yellowing) of mature leaves and stunted growth when compared to the control.

Symptoms of  advanced stages of nitrogen deficiency appear as necrotic (dead) and cholorotic oldest leaves and severely stunted growth when compared to the control. Note that after six weeks, the control plants also had some necrosis and abscission of the oldest leaves, but not to the degree of the nitrogen-deficient plants.

Phosphorus (P)

Withholding phosphorus resulted in stunted plants. There was decreased lateral branching, shorter internodes and large root systems (twice the size of the control). Leaves were smaller and darker green.

Potassium (K)

Potassium-deficiency symptoms took a long time to appear (almost 70 days), but then seemed to happen all at once. Plants took on a wilted appearance, which is logical since potassium helps regulate turgor pressure and other osmotic functions. Symptoms included necrotic mature leaves and upwardly curling younger foliage.

Calcium (Ca)

As with other perennials tested, calcium-deficiency symptoms appeared relatively rapidly in Veronica. Within 10 days, new foliage was severely curled and otherwise distorted with zones of chlorosis and necrosis. Plants declined rapidly thereafter.

Magnesium (Mg)

Magnesium-deficiency symptoms on the perennials tested continue to defy textbook descriptions. Even after eight weeks of withholding magnesium, symptoms were not very striking. There was a decrease in lateral branching, decreased root size and dark-green zones on lower mature leaves.

Sulfur (S)

Ninety days after the beginning of treatment, the most notable symptom was the limited growth when compared to the control, including smaller leaves and shorter internodes. There was some chlorosis on younger and recently matured leaves.

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Boron (B)

The importance of providing sufficient boron for development of new tissue was evident. New leaves on boron-deficient plants were distorted (dimpled and chlorotic).

New root growth was stunted with brown nodules at the tips. Overall root mass was greatly reduced compared to the control (not pictured)

Copper (Cu)

Copper deficiency resulted in highly distorted new growth. Leaves were straplike, twisted and chlorotic. Mature foliage was flecked with necrotic spots. Note the interesting proliferation of auxiliary shoots at each leaf node.

Iron (Fe)

There was a rapid onset of iron-deficiency symptoms with interveinal chlorosis and a folded distortion of the youngest leaves.

Late in the study, all but the oldest leaves exhibited interveinal chlorosis as a result of iron deficiency. Overall shoot growth was reduced.

Manganese (Mn)

Veronica was slow to express manganese-deficiency symptoms. Shoot growth displayed very short internodes and a downward curling of leaves when compared to the control. A few chlorotic and necrotic spots appeared on mature leaves.

Zinc (Zn)

Zinc-deficiency symptoms also took quite a while to appear but differences in growth were noted after six weeks. The internodes were so short they gave a rosette appearance with the leaves appearing “stacked” on each other. Recently matured leaves were very dark green and mottled with a bronze cast.

- Holly L. Scoggins, Allison Byrd and Velva A. Groover

Holly Scoggins is associate professor, Allison Byrd is a former graduate research assistant, and Velva Groover is senior research technician, Virginia Tech University, Department of Horticulture, (540) 231-5783; perennials@vt.edu.

The authors thank Fred C. Gloeckner Foundation for grant support, Yoder-Greenleaf for plant material and Quality Analytical Laboratories for tissue analysis. The authors thank Virginia Tech University metabolomics specialist Joel Shuman for technical assistance, and partners in the study, University of Florida assistant professor James Gibson and his staff and students at West Florida Research and Education Center in Milton , Fla.

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