Growth of nine ornamental palm species cultivated under a shade gradient

Abstract

We evaluated the growth of 9 ornamental palm species kept under a shade gradient created by black polypropylene screens that yielded 40, 50 , 60 , 70 and 80% shade, plus a 70% aluminizednet shade treatment and a control consisting of plants grown under full sun. The species evaluated were Caryota mitis, Chamaedorea costaricana, Chamaedorea tepejilote, Dypsis lutescens, Lícuala elegans, Phoenix roebelenii, Ptychosperma macarthurii, Roystonea regia, and Veitchia merrillii. Plant height, length of the youngest fully expanded leaf, and number of leaves per plant were measured during a twoyear period. In general, plant height and leaf length were lower under 0-40% shade, increased under 50-70%, and declined under 80%. C. tepejilote, C. mitis, L. elegans y P. macarthurii behaved as obligate shade plants and did not survive under full sun. C. costaricana and D. lutescens survived full sun exposure, but their growth reached highest values under 50-60%. P. roebelenii, R. regia and V. merrillii showed reduced growth at 0-40%, but growth improved under all other shade levels employed. In general, 1-2 years are appropriate for nursering fastgrowing palms (Chamedorea spp, D. lutescens, R. regia) in tropical shade houses. Slow-growing palms (L. elegans) may be kept for 3-5 years in a shade house. Strategies for the use of shade gradients in time and space, according to the requirements and economic uses of palm species, market requirements, and plant production cycles, are discussed.