by Nanette Londeree, Master Rosarian
SYMPTOMS
Cupped leaves, twisting or bending of leaf petiole
Distorted and stunted fan-shaped leaves
Strange looking, thickened growth, often dark red or purple in color
Prominent leaf veins, reduction of leaf interveinal areas
Delayed leafing in spring
Chlorosis
Plant death
CAUSE
Exposure to postemergent herbicides like Roundup (glyphosate)
OPTIMAL CONDITIONS
May appear any time after exposure
Often seen in spring after plants have been exposed in fall or winter, during dormancy
Dry weather (must remain dry for 24 hours after exposure to the herbicide); any amount of wind that results in spray drift
TREATMENT
Prevention:
Don’t use this type of herbicide in the garden
Protect plants from spray drift from adjacent properties if possible
Elimination:
Cut out damaged portions of plants if not too extensive
Improve vigor of plant with good cultural practices especially sufficient water
Remove badly damaged plants; they are not likely to recover
GOOD GUY / BAD GUY?
A very bad guy – it can destroy roses and any other plant it contacts
Photo of Herbicide Damage is by Baldo Villegas from the extraordinary webpage: http://members.tripod.com/buggyrose/iabioticdisorders.htm