Have you seen these symptoms in ornamental plants, especially oaks, after treating nearby turf with metsulferon-methyl (MSM)?
Over the past few years, there have been numerous inquiries regarding damage to ornamental plants growing near turfgrass areas that have been treated with metsulfuron-methyl-containing herbicides. Symptoms most often seen are stem die-back, brown “fried” or “scorched” foliage, delayed leaf appearance, and patches of necrosis (dead tissues) in the phloem (plant’s vascular tissues). Injury symptoms are typically reported two to four weeks following applications made during hot and dry weather (although not exclusively).
For more information see the complete UF/IFAS publication here: http://edis.ifas.ufl.edu/fr400