Plug source and growth retardants affect finish size of bedding plants

Eight bedding plant species were grown from plugs obtained from two sources . The plugs were transplanted into jumbo sis packs and sprayed with a solut ion of chlormequat/daminozide with concentrations of 1000/800, 1250/1250, o r 1500/5000 mg.L-1 when new growth was approximate to5 cm in height or widt h. Three different species were grown in the fall (Dianthus chinensis L.,'T elstar Mix', Petunia xhyhrida Hort. Vilm.-Andr., 'Dreams Red', and Viola xw ittrockiana Gams,,'Bingo Blue'), winter [Antirrhinum majus L., 'Tahiti Mix' , Matthiola incana (L.) R. Br., 'Midget Red', and P. xhybrida, 'Dreams Mix' ], and spring [Catharanthus roseus (L.) G. Don, 'Cooler Pink', Salvia splen dens P. Sellow es Roem. & Schult., 'Empire Red', and Begonia xsemperflorens -cultorum Hort., 'Cocktail Mix']. The treatments significantly reduced fini shed plant size of all species for each season. There was a significant dif ference in finish size between sources for Dianthus, Antirrhinum, Matthiola , Catharanthus, Salvia, and Begonia. The efficacy of chlormequat/daminozide also differed for each source of Dianthus, Matthiola, and Begonia, but the treatments minimized the differences in finish size between sources for Pe tunia and Viola. Chemical names used: (2-chlorethyl) trimethylammonium chlo ride (chlormequat); (N-dimethylaminosuccinamic acid) (daminozide).