The 2012 ASHS Annual Conference

Roses planted in landscapes are a common feature in California.  The severity of pruning has anecdotally been linked to flower production and flower quality but there are few reports of landscape-based research.  We established a blocked trial with over 500 roses of 8 varieties.  There were four pruning treatments: unpruned; pruned to a height of 0.91 m and 5 primocanes; pruned to 0.46 m and four canes; and pruned to 0.15 and three canes.  Flower quality and stem length were unaffected by pruning treatment.  Quantity of flower production was greatest in unpruned roses.  There were few differences between moderate pruning severity treatments (0.91 and 0.46 height treatments).