My Crimson King Norway maples are slowly dying, one by one. I see trunk cracks but can't see any disease or insects. How can I save the rest?
Norway maples in general are notorious for strangling themselves to death. The roots often encircle and crisscross over the base of the trunk, cutting off nutrients and water from the root system. Death can take decades but often happens just when trees reach a pleasing size and shape. A dead giveaway is when there is no natural flare on a side of the trunk base; instead, the trunk is flat, going into the soil. You cannot save your trees. These trees are also not recommended because they are exotic, invasive plants. Replant with a different species, preferably native. Native trees provide the most benefits to wildlife.
Leaves on my cherry tree are being eaten up. They're covered with holes and reddish-brown spots, turning yellow and falling off. What is eating my cherry tree, and what should I do?
Nothing is eating your cherry tree. It has cherry leaf spot disease. This fungus causes spots, which eventually die; then the dead tissue falls out of the spot, leaving a hole. The fungal spores overwinter on fallen leaves. You can control this by raking up and disposing of leaves in fall.
University of Maryland Extension's Home and Garden Information Center offers free gardening and pest information. Call 800-342-2507 or send a question to its website at extension.umd.edu/hgic.
Coleus growing in a sunny bed? Unheard of … until now. Though long grown as colorful foliage in shade, new varieties pass the direct-sun test with flying colors, literally. In red, lime, peach, yellow, burgundy and pink, plus patterned and frilly leaved varieties, the beauty and breadth of sun coleus is incredible. Coleus is easy to grow and low-maintenance in well-drained soil of medium fertility. Colors are best when not heavily fertilized. Many grow to 1-2 feet , but some are larger, so read labels. Pinch growing tips to encourage fullness; cuttings from tips root easily. Coleus does well in containers and garden beds, and can overwinter as houseplants.
—Christine Pfister McComas