Care for a river birch tree by placing it in a location that receives eight hours of full sun per day and watering it regularly. For hot climates, place the tree in partial shade. Some varieties can develop sun scorch if exposed to full sunlight all day.
Because this tree requires slow, consistent moisture, use a drip irrigation system, and turn it on once a week for 15 minutes. Ensure the soil from the base of the tree to its drip line is moist 12 inches deep. If it's not, water the tree for another 15 minutes.
To keep the soil moist, add a 3-inch layer of mulch around the base of the tree in a 6- to 12-foot diameter, making sure it doesn't touch the trunk, as this can cause rot. Only fertilize the tree if it does not grow, grows slowly or does not produce green foliage. Do a soil test to find out what nutrient deficiencies need to be corrected making sure the soil pH is between 6.8 and 7.2. Add the corresponding fertilizer. Water the tree immediately after applying fertilizer. Prune the tree for shape in the fall, but cut back damaged or dead limbs as they develop.