Q: My laceleaf Japanese maple leaves have become brown-tipped or gray-spotted, and some leaves have curled up entirely. I know that trees will be shedding leaves soon, but is there anything I should do to help the tree? It seemed to start earlier in the summer and has gotten worse in recent weeks.
A: Right now, little needs to be done except to monitor the plant for watering needs. (Visit our Watering Trees and Shrubs page for guidance.) Even though above-ground growth is finished, roots still need to stay healthy to keep the wood and buds for next year alive, and the drought that impacted much of Maryland this year stressed lots of plants. Branch dieback during the dormant season can be caused by underwatering the year prior, especially if the autumn or winter is unseasonably dry.
While powdery mildew and a couple of leaf spot fungi can damage Japanese maple leaves, most of the foliage damage seen by late summer and autumn is scorch. Scorch is physical damage to leaf tissue from high heat, intense light, and/or inadequate moisture in the root zone. It won’t necessarily manifest while it is happening, so like a sunburn that becomes more noticeable after the fact, scorch symptoms won’t appear until the damage is already done. Moisture evaporating out of leaf pores is a plant’s air-conditioning (though it serves several vital functions in addition to that), so when there isn’t enough soil moisture for roots to keep leaves well-hydrated, a plant is more vulnerable to scorch.
Nothing will heal injured leaves, though scorch is just an eyesore. For mild to moderate scorch, like we tend to see on those laceleaf varieties of maple, serious long-term impacts are fortunately not as likely. Still, its appearance signals that the root area is probably getting too dry, and more careful monitoring for watering may be needed to avoid worsening or repeating the condition.
Q: Tough-skinned, rounded lumps have appeared in a spot in my lawn, where it looks like something burst out of the ground and then partially collapsed. It kind of looks like a puffball, but isn’t the usual shape or texture of a typical mushroom. Is it fungal, and is it going to blight my grass?
A: It sounds like you’ve found a species of scleroderma, a group of mushrooms also known as Earthballs (not the same fungus as a puffball mushroom, which is similar in shape but not in color or texture). Dark spores are contained in the ball’s interior and are released as the structure collapses and breaks apart.
These fungi might look alarming if they’re large or numerous, but they are not plant parasites and will not cause disease in the lawn or nearby plants. In fact, they are ectomycorrhizae, which means they colonize the exterior of plant roots and help them absorb moisture and nutrients. (They can also decay dead wood, helping to recycle nutrients back into the soil.)
You don’t need to remove scleroderma mushrooms, and like other mushrooms, they will go away on their own in time. A fungicide will not be of any use, but a shovel might:If a curious child or pet tries to eat one, then either keep them away from it until it disappears or remove the mushroom before they can enter the area. The fungus can keep periodically producing mushrooms as long as it has a food source and the conditions are suitable for reproduction, usually after wet weather.
University of Maryland Extension’s Home and Garden Information Center offers free gardening and pest information at extension.umd.edu/hgic. Click “Ask Extension” to send questions and photos.
