Jerry from Bethel Springs,tn. writes
For black spot on roses, you should start seeing results within a few days, but you can repeat applications of Ferti-lome Liquid Systemic Fungicide II every 10 days as needed. Be sure to allow the product to dry completely before watering. Per the product label, this product may not provide 100% control of severe black spot infestations.
Answer last updated on: 05/18/2021