Response of Conifers to Growth Retardants

Abstract

Application of four growth retardants (B-995, AMO-1618, Phosfon-D, and CCC) to seedlings of Arizona cypress, coastal redwood, Douglas fir, and Coulter pine showed that: (a) growth of Arizona cypress and coastal redwood treated with B-995 or AMO-1618 was retarded, and this effect was partially reversed with a 10-ppm gibberellin spray; (b) Arizona cypress was stunted by Phosfon-D but was not affected by CCC; (c) results with Douglas fir were inconclusive because of bud dormancy on treated plants; (d) growth of Coulter pine was retarded by B-995 or Phosfon-D but was unaffected by AMO-1618 or CCC.