Leaf Spot on Rudbeckia
The beautiful bright yellow daisy-like flowers of rudbeckia are often overshadowed by thediseased foliage.
A bacterial and several fungal leaf spot diseases causepurplish-black spots on the leaves of rudbeckia. Severe infestation can totallyblacken the leaves and cause the plants to dieback a bit earlier in fall.
Fortunately, most of the diseases are cosmeticand the plants will continue to flower and return each year.
Reduce the risk of this disease by providing adequate light andair circulation around the plants. Use asoaker hose or watering wand to apply water directly to the soil whenneeded.
In the fall, remove and destroy all diseased plant parts.
If disease is a yearly problem, you can use a copper containingfungicide as a preventative. Or plant something slightly shorter in front ofthese plants to mask the discolored leaves, but allow the flowers to showthrough.
Try growing other rudbeckias that are less susceptible to thesediseases. The great coneflower (rudbeckia maxima) is native to NorthAmerica and grows 5 to 6 feet tall. Its large, yellow daisy-like flowers areheld high above the 12- to 18-inch long blue green leaves at the base of the plant.
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