Japanese maple trees, which have a formal name of acer palmatum, have delicate, lacelike leaves that are a vibrant red colour. It is a versatile species that grows equally well in the ground or in a pot. Some gardeners even prune the Japanese maple into a bonsai form. Potted Japanese maples must be transferred to larger pots periodically to prevent the roots from becoming stunted. The proper time to repot a Japanese maple is in the mid-spring.
Water the soil in the Japanese Maple pot more frequently two to three weeks before repotting to keep it constantly moist by not soggy. Well watered trees respond better to repotting than dry ones.
Use a pot that is 2 inches larger in diameter than the pot the Japanese Maple is currently in. Fill the bottom of the pot with 1/2 to 1 inches of small stones to provide proper drainage.
Fill a bucket with a mixture of half potting soil and half ericaceous compost. Mix the two together well and place a 1- to 2-inch layer of it in the bottom of the pot.
Tilt the Japanese maple tree sideways until the old pot lays on its side. Grasp the base of the Japanese maple trunk and pull it gently out of the old pot.
Place the roots of the tree into the new pot and fill in the remainder of the pot with the soil mixture. The soil mixture should reach 1 to 2 inches below the top rim of the pot.
Water the soil in the new pot until it drips out of the bottom drainage holes.
Repot your Japanese Maple trees every two to three years. Ericaceous compost is sometimes simply called acidic compost.