Most Japanese maple varieties can withstand minimum annual temperatures as cold as minus 15 to minus 25 degrees Fahrenheit, making them suitable for landscapes located in a wide range of climates. One of the most important elements of caring for your Japanese maple tree is selecting the right planting location. Choose a spot for your Japanese maple that has well-draining soil, receives full morning sunlight, and provides protection from afternoon sun and high winds. Japanese maples grow best in fairly acidic soils, so you can amend your soil if needed with pine bark mulch when you’re planting the tree.
Water your Japanese maple tree evenly and deeply once every week when you receive little or no rainfall. Water the tree during the growing season, and then water only once a month as needed in the fall.
Spread a 1-inch layer of organic compost around the base of the Japanese maple in early spring. Ensure that the compost layer covers the canopy area on the ground and is about 1 to 2 inches away from the trunk.
Feed your Japanese maple tree once each year in the spring with a well-balanced fertilizer, such as a 10-10-10 NPK (nitrogen-phosphorus-potassium). Follow the application and dosage instructions on the label.
Prune your Japanese maple once every two or three years to thin out overcrowded branches. Prune away any damaged, diseased or dead wood in the winter, when the leaves have fallen from the tree, and remove any crowded stems or small branches.
Protect your Japanese maple tree from late spring frosts. Cover the ground around the tree, but not touching the trunk, with an additional 2-inch layer of bark mulch. Prune away frost-damaged stems and leaves in the spring.
Inspect your Japanese maple tree regularly for aphid infestations by looking for the insects themselves, as well as distortion of the tree’s leaves and new-growth shoots. If you have aphids on your tree, spray the tree with an insecticidal soap according to the directions on the label.
Watch out for botrytis, a fungal disease that can cause brown spots on your tree’s leaves that turn into a furry grayish mold. Treat botrytis disease by avoiding over-watering the tree, pruning away and burning any infected stems or leaves, and spraying the tree with a copper-based fungicide, such as a Bordeaux mixture.