Use extreme caution when applying pre-emergent herbicides in close proximity to bulb beds. Products such as Ronstar or OHI, Goal and Prowl (Oxfluorfan and Pendamethalin) may cause flower abortion when used on or near Tulip beds.
If you must use pre-emergent herbicides, we suggest Betasan, Chloramben, Dacthal, Devrinol, Enide, Eptam or Treflan. Keep in mind that many of these products can prove harmful to your bulb beds and should be used with extreme caution. Post-emergent herbicides such as Fusilade or Poast seem to cause less problems and should be considered.