With the hot and humid weather we have had this week Black Spot is starting to pop up on our landscape plants.Black Spot is a fungus that affects roses but can also be found on other ornamental and garden plants.Black spots presents the greatest problems when leaves on plants stay wet for 6 hours or more when the weather is hot and humid.
Black spot produces round black spots with fringed margins that can be up to about 1/2 inch in diameter.The spots form on the upper sides of the leaves and leaf tissue surrounding the spots turns yellow.Usually lower leaves are infected first and infected leaves often fall off the plant early.
Black spot overwinters in fallen leaves and branches. Water splashing on the soil under plants can catapult the spores onto plants as well.
A few ways to control or prevent Black Spot:
Regular fertilization to plants, this will help them become stronger and protect them from disease.
Remove any debris from beds in the fall to prevent black spot from overwintering.
Don’t compost if you think there are infected branches or debris
When watering, apply water directly to base of plant rather than on the leaves.