How to Prevent Holly Leaf Spot

The leaves of my newly-planted ‘Carissa’ hollies are covered in black spots. What should I do? Will this do long-term damage to my hollies? – Nikki

It sounds like your holly plants have been infected with a fungal disease known as holly leaf spot, sometimes called holly tar spot. It can be caused by several different fungi, but the symptoms are similar: the leaves develop black, brown, or yellow spots. Eventually, the infected leaves fall off the plant, leaving your holly bare and spindly. Leaf spot usually develops during wet spring weather, and the leaves begin dropping throughout the summer and fall.

The good news is, holly leaf spot is rarely fatal, and your bushes will likely recover if you take steps to keep the problem from getting worse. The plant damage comes from the stress of losing leaves, so treatment and prevention focus on protecting new holly leaves so that the plant can recover. Here’s how to go about it.

Treatment and Prevention of Holly Leaf Spot

Follow these steps to treat and prevent fungal leaf spot on holly:

• • Pruning: If your holly is really dense, prune and thin out some branches to increase air circulation and to allow sunlight to penetrate the plant.

‘Carissa’ holly

• • Watering: Water your hollies before noon, so that the leaves have a chance to dry off during the day.

• • Keep Plant Healthy: A strong plant can easily recover from leaf spot. See our article on How To Grow Hollies for tips on keeping your plants happy.

• • Remove Diseased Leaves: Gently shake your holly, or lightly sweep with a rake, to encourage as many diseased leaves to fall off as you can. Then bag up the leaves and throw them away. You can probably put them in a really hot compost pile, but it’s generally recommended to throw diseased plant debris either into the trash or in an out-of-the-way composting area.

• Apply Fungicide: Fungicides may help reverse the earliest stages of leaf spot but are mostly used as a preventative on unaffected leaves. They are really only necessary if the other measures above have failed.

Further Information

• Holly Leaf Spot (Umass Extension)
• How to Grow Holly