I left a small boiled potato on my kitchen counter overnight. Next morning, the potato's inside was partially eaten, but peel was scattered around the potato. What could have eaten the potato? Looked up mice and found they do like boiled potato, but the skin is not good for them. I checked for mouse droppings for two mornings, but did not find any. Do I have a very knowledgeable mouse who also does not leave droppings?

Mouse with smarts? Yes. Exceptional? Probably not. Mice, like other animals, either know instinctively what foods to eat or else test a potential food with a nibble and learn to avoid those that taste bad or sicken them. Mice don't commonly leave droppings out in the open, but droppings could be in walls or places inaccessible to you. As weather cools, mice seek warm shelter and often move indoors. Plug holes as small as 3/8 inches. Best placement for snap traps is along walls, in or under cabinets, and in suspended ceilings. Search mice on the HGIC website for more tips. Avoid glue boards that kill mice inhumanely or leave you with a live mouse you must kill. Live traps are available.

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My husband just noticed a very rough, scabby-looking patch in the bark about three-quarters of the way up the trunk of a tree we just planted this spring. It's dark, dry and sort of oblong, but not like a scar left from pruning off a branch. Is it possible to fix this, or is it even something to worry about?

Sounds like an old tree wound. You cannot remove it. You cannot “fix” it. Trees do not heal like humans do. When they are wounded, the damaged area remains, but the tree seals off the wound by compartmentalizing it so rot does not spread to the rest of the tree. It appears that this has been done successfully by your tree. There may be some disruption in the flow of water and nutrients to the part of the tree directly above the wound. Watch that part for growth changes or dieback. Also watch for change in the wound, such as rotting. Much depends upon the size of the wound.

University of Maryland Extension's Home and Garden Information Center offers free gardening and pest information at extension.umd.edu/hgic. Click “Ask Maryland's Gardening Experts” to send questions and photos.

Digging deeper

Jewelweed, Spotted Touch-Me-Not

Impatiens capensis

The fun starts when the flowers fade. Jewelweed is not a cultivated plant, as its other common name suggests, but its seeds have a cunning plant advantage: dehiscence. Jewelweed's blue-green leaves, white underneath, usually show up unannounced in a relatively moist, shady area. Reaching 1½ to 5 feet high, it's a native annual whose nectar draws butterflies and hummingbirds, and whose seeds feed birds and other creatures. From May to October, the tubular 1-inch flowers bloom in orange, occasionally white or yellow, with rusty freckles and a spur. In fall, dehiscent seed capsules develop. Dehiscent means seed capsules or pods have a built-in weak spot that breaks to release seeds. While some plant seeds simply spill out, jewelweed seeds explode out. Great fun for kids, big and small. Native Americans applied the leaf juice to relieve poison ivy and skin rashes. Touch it not, unless you want more of this wildflower. — Ellen Nibali