Preventing establishment of exotic shrubs (Cytisus scoparius (L.) Link. and Cytisus striatus (Hill)) with soil active herbicides (hexazinone,sulfometuron, and metsulfuron)

A greenhouse study was conducted evaluating the potential for commonlyused forestry herbicides to control germination success of Scotch broom(Cytisus scoparius (L.) Link.) and Portuguese broom(Cytisus striatus (Hill). Three herbicides, hexazinone,sulfometuron and metsulfuron, were evaluated at six rates encompassing normalrates used for herbaceous weed control. The data suggest that these herbicidesapplied prior to establishment can strongly affect seedling establishment ofthese species even though they are ineffective on mature individuals.Hexazinonestrongly affected both the final weight of surviving seedlings and theprobability of seedlings from broom species to survive to week nine.Sulfometuron had no effect on survival probability of either species butreducedfinal dry weight and delayed true leaf development at increased rates.Metsulfuron reduced the survivorship potential of Scotch broom but notPortugesebroom. Final dry weight decreased and development of true leaves was delayedforboth species treated with metsulfuron. These results suggest that preemergencetreatments with hexazinone may provide an effective method of preventing broomestablishment. Sulfometuron and metsulfuron were not as effective at preventingsuccessful establishment as hexazinone.