General Information


RONSTAR FLO HERBICIDE is a selective, preemergent herbicide for control of many annual grasses and broadleaf weeds in turf and on a variety of woody ornamental shrubs and trees. RONSTAR FLO HERBICIDE controls weeds by killing the young weed seedlings as they come in contact with the herbicide during germination.

Apply RONSTAR FLO HERBICIDE with a properly calibrated sprayer that will apply the spray solution uniformly (uniform application is essential for satisfactory weed control). Calibrate the sprayer prior to use, according to the manufacturer’s directions and check daily to be certain that the equipment is working properly.

Do not allow domestic animals to graze treated areas. Avoid contamination of water intended for irrigation and domestic use.

Limitations, Restrictions, and Exceptions


WOODY ORNAMENTAL SHRUBS AND TREES, CONIFER NURSERIES, AND ORNAMENTALS ON COMMERCIAL PROPERTIES: Apply RONSTAR FLO HERBICIDE prior to weed seed germination, as a directed spray to the soil surface or as an over the top spray only on labeled species. RONSTAR FLO HERBICIDE can be applied to both newly transplanted and established plants. Application can be made to actively growing or dormant plants. However, RONSTAR FLO HERBICIDE must not be applied during bud break or during the 4 weeks after bud break.

Rainfall or overhead irrigation (one-half inch) immediately after application of RONSTAR FLO HERBICIDE will improve weed control activity. Rainfall or overhead irrigation immediately after over the top sprays is required to move the RONSTAR FLO HERBICIDE from the foliage to the soil surface.

RONSTAR FLO HERBICIDE must not be mixed into the soil. Cultivating or disturbing the soil may reduce the weed control activity of RONSTAR FLO HERBICIDE. Do not apply in greenhouses as plant injury may result from co-distillation of RONSTAR FLO HERBICIDE active ingredient onto leaf surfaces in condensation.

The maximum single application rate is 3.7 fl. oz. of product per 1000 sq. ft. and no more than 2 applications per year.

The maximum amount of product allowed per year is 5.55 fl. oz of product per 1000 sq. ft. (1.89 gallons of product per acre per year) (equivalent to 6 pounds ai/A/year), except in areas where there is heavy weed infestation. In areas of heavy weed infestation, the maximum amount of product allowed per year is 7.4 fl. oz of product per 1000 sq. ft. (2.52 gallons of product per acre per year) (equivalent to 8 pounds ai/A/year). For best results, water-in product as soon as practical after application.

PLANT TOLERANCE: RONSTAR FLO HERBICIDE can be used as directed spray to the soil surface on a wide variety of container and field grown woody ornamental shrubs, trees, conifers, and herbaceous plants in nurseries. RONSTAR FLO HERBICIDE may be used as an over the top spray in a minimum of 1 gallon of water per 1000 sq. ft., at the labeled rates, on the following ornamental species only:

Arborvitae, Japanese Barberry, Boxwood, Baby’s Breath, Eastern Red Cedar, Cranberry, Hinoki Cypress, Nootka Spound Cypress, Sawara Cypress, Evergreen Euonymus, Douglas Fir*, Fraser Fir*, Grand Fir*, Noble Fir*, Gladiolas, Canadian Hemlock*, Chinese Holly, Japanese Holly, Kurogane Holly, Purple Hopseed Bush, Andorra Juniper, Blue Rug Juniper, Common Juniper, Creeping Juniper, Oleander, Ophiopogon, Eastern White Pine, Mugho Pine, Scotch Pine, Raphiolepis, Blue Spruce*, Statice

Local conditions may affect the use of this chemical. Consult State Agricultural Experiment Station or Extension Service weed specialists for specific recommendations for local weed problems and for information on possible lower dosages.

*Not currently registered for use on Fir, Hemlock, and Blue Spruce in California.

- Not currently registered in California for use on Bristly Oxtongue, Cheeseweed, Fiddleneck, Fireweed, Shepherdspurse, Sow Thistle, Annual Bluegrass, Annual Sedge, Ripgut Bromegrass, and Wild Oats

Common Groundsel, Evening Primrose, Galinsoga, Liverwort, Prostrate Spurge, Swinecress - Use 2.8 fl oz of product per 1000 sq. ft.

Restricted Entry Interval

12 hours