• slide
  • slide
  • slide
  • slide
  • slide
  • slide
  • slide
  • slide

Tar Spot Disease on Maples

Don’t let the black tar-like spots on your maple tree make you fret. Though one of the more noticeable, it is one of the less damaging of the fungal leaf spot diseases. 

Tar spot symptoms look as if someone dripped tar on the leaves. A European tar spot that has found its way to North America can also attack Norway and striped Maples. These spots are thinner, less tar-like and surrounded by a yellow halo. 

You’ll see more spotting during summers following a wet spring. The disease organism survives the winter on the tar spot infected leaves lying on the ground. Raking and destroying the leaves will help reduce the source of infection but is usually not practical. Everyone in the area must do the same in order for this method of control to be effective.

So be patient and wait for a drier spring and the disease to run its course.

A bit more information: Chemical control is not practical, nor recommended. You must treat before the spots have developed and have complete coverage. This is difficult on large mature maple trees. Proper care is the best defense against this and other diseases. Water properly and mulch trees to keep them healthy.

Upcoming Live Events
& Webinars


May 3, 2025
Low-Maintenance Gardening
Merton, WI
Register here

May 7, 2025
FREE WEBINAR:
Vertical Gardening
Register here


May 10, 2025
Ask the Plant Doctor Q&A
Ebert's Greenhouse Village
Ixonia, WI

May 11, 2025
Ask the Plant Doctor Q&A
Ebert's Greenhouse Village
Ixonia, WI

May 15, 2025
FREE WEBINAR:
7 Steps to Managing Water on Your Property

Register here

May 17, 2025
Ask the Plant Doctor Q&A
Ebert's Greenhouse Village
Ixonia, WI

May 18, 2025
Ask the Plant Doctor Q&A
Ebert's Greenhouse Village
Ixonia, WI

June 4, 2025
FREE WEBINAR:
Attracting Hummingbirds

Register here

June 8, 2025
Selecting the Right Hydrangea
for Your Landscape

Ebert's Greenhouse Village
Ixonia, WI

June 14, 2025
Houseplants 101
Ebert's Greenhouse Village
Ixonia, WI

June 20, 2025 (event 6/20-6/22)
Pollinator Celebration
Vino in the Valley
Maiden Rock, WI
Register here

WATCH ON-DEMAND WEBINARS

Learn More

Book an Appearance

Learn More

Enter to Win

Wild Valley Farms' Wool Pellets 
& Gardener's Bundle 

ENTER NOW