Suitable for growing in U.S. Department of Agriculture plant hardiness zones 8 through 11, silver dollar plant (Eucalyptus cinerea) displays round, grayish-green foliage often used in flower arrangements and bouquets. This fast-growing tree, also known as argyle apple, reaches a mature height of 15 to 45 feet or more. However, in the home garden, size is usually limited to 20 to 30 feet. Silver dollar plant is often grown in containers and pruned to maintain a shrub-like size and shape. It tolerates dry conditions and prefers slightly acidic soil.
Water the silver dollar plant slowly with a garden hose or soaker hose until the soil is wet to a depth of 2 to 3 feet, then let the soil dry before watering again. Don't water the plant if the soil is damp from a rainfall or a previous watering. Avoid frequent, shallow waterings, as deep waterings develop plants with long, sturdy roots. Water potted silver dollar plants until water runs through the drainage hole, then let the potting soil dry.
Feed silver dollar plants with a balanced, 10-10-10 dry fertilizer in early spring. Feed small, shrub-sized plants 1/2 to 1 cup of fertilizer with a total of no more than 1 tablespoon per foot of height. To feed large trees, measure the diameter of the trunk about 4 feet from the ground, and then apply 1 pound of fertilizer for each inch. Sprinkle the fertilizer evenly on the ground under the tree, then water deeply.
Prune silver dollar plant in early spring. Remove dead and damaged shoots, as well as branches that rub across other branches. Trim the tree to the desired size and shape if you want to grow silver dollar plant as a shrub. Remove lower branches if you want to create a tree shape. Cut the branches at a branch or bud to prevent stubby growth and promote a natural appearance.