Plant materials. Rooted cuttings of zonal
geraniums were obtained from a commercial
propagator (Busch Greenhouses, Denver).
One-half of the rooted cuttings were taken
from stock plants that had been treated with
ethylene in the form of ethephon, to prevent
flower formation and ensure maximum yield
of cuttings. Ethephon applications were initiated
28 d after establishment of geranium
stock plants and continued at 21 d intervals for
a total of 3 applications at 400 mg·L–1 a.i. and
32 L·m–2.