SHADE INFLUENCES PLANT-GROWTH, LEAF COLOR AND CHLOROPHYLL CONTENT OF KALMIA-LATIFOLIA L CULTIVARS

The effect of shading during nursery production on the growth, foliage color, and foliar chlorophyll content of container-grown Kalmia latif olia cultivars was investigated. Five cultivars were grown under 40% s hade, 60%, shade, or full sunlight for a 2-year production cycle. Duri ng the first gear of production, there were no significant differences in measured growth characteristics for most cultivars in response to light treatment. Shade improved foliar color by decreasing Lightness ( L), decreasing chroma, and changing hue angle from a yellow-green to a darker green. Foliar chlorophyll concentration increased under shade . In the second year of the production cycle, the response of foliar c olor and chlorophyll concentration to shade was similar to that observ ed in year 1. Plant size, number of branches. leaf area, leaf dry mass , and stem dry mass decreased linearly with increasing shade in gear 2 . Although shading improves foliar color, it probably should not be em ployed for container production of Kalmia latifolia in cool, northern production areas due to reduced plant growth during gear 2. Shade mag be useful in the first gear of production to enhance foliar color with out reducing shoot growth.