The Mimosa tree's delicate trunks and unique pink flowers make it a popular landscape ornamental. And its low-maintenance needs don't hurt its popularity either. Unlike more particular ornamentals, the mimosa only needs a minimal amount of care. It is quite drought tolerant and a light feeder. Simply provide it with a few inches of supplemental water and annual or semi-annual applications of fertilizer and it will grow happily for years.
Take a sample of the soil at the base of your mimosa tree into your local county extension office for testing. Use a spade to dig to a depth. Then extract roughly 1 cupful of soil at that depth and deposit it into a clean plastic container with a lid. The resulting test will alert you of any deficiencies your soil might have and dictate the amount of fertilizer that your mimosa tree will need over the next few years. Ideally, your mimosa tree's soil should be tested once every four years. If you do not conduct a soil test or your test reports no major deficiencies, use the following guidelines for fertilization.
Apply a 10-10-10 granular tree fertilizer (4 ounces per 100 square feet) in early spring before the tree produces new growth. Spread the fertilizer in a 3-foot-wide circular band that begins just inside your tree's drip line.
Water the area with 1 to 2 inches of water to help the fertilizer reach the mimosa tree's roots.
Reduce the amount of fertilizer to 1.5 ounces per 100 square feet every two years once your mimosa tree reaches maturity (around 30 feet in height). Once the mimosa tree is done growing rapidly, its fertilization needs are much lower. In fact, fertilization can be skipped altogether if you leave the mimosa tree's leaves at its base to provide a natural fertilizer.