Never growing more than six inches a year, the very slow growing Japanese umbrella tree (Sciadopitys verticillata) bears tufted clusters of deep green evergreen needles. Usually becoming a spire-like or pyramidal tree after decades of growth, plant this tree in anticipation of your grandchildren enjoying its mature beauty. Growing 20 to 30 feet tall and 15 to 20 feet wide, it makes a fine specimen in U.S. Department of Agriculture Hardiness Zones 5 through 8.
Locate a spot in your garden that receives at least four to six hours of direct sunlight daily. The Japanese umbrella tree prospers in partial shade to full sun exposures, where it basks in the sun for more than 10 hours daily.
Examine the soil in the location where you want the tree to grow. It should be fertile, indicated by other plants already growing there, such as grass, wildflowers or weeds. Digging into the soil with a shovel must reveal a moist soil that is deep, lacking any rocky obstructions that would make planting the tree difficult.
Dig a planting hole the same depth as the Japanese umbrella tree's root ball. Make the planting hole two to three times as wide as the root ball.
Fill the empty planting hole with six inches of water from a garden hose, and note the length of time it takes for the water to fully drain and empty the hole. If it takes longer than three or four hours to drain, consider repeating Steps 1 through 4 again in another location. The soil must not remain soggy or waterlogged, as this will lead to root suffocation and tree demise over time.
Place the tree in the planting hole, back-filling soil around the root ball. Lightly tamp the soil with your hand or foot to help compact the soil gently, adding soil until the top of the root ball matches the soil level at the hole's rim. Do not plant the tree too deeply. Use excess soil to create a three- to four-inch berm around the tree to act as a catch basin for irrigation water.
Add three to four inches of water from a garden hose or sprinkling can to the tree to compact and moisten the soil. Allow the water to soak away and repeat again two more times to ensure all air pockets in the planting hole disappear. Place additional soil in the hole as needed if the soil line drops below the height of the tree's root ball after the watering and compaction.
Place a layer of organic mulch around the tree base at a depth of three to four inches. Extend the mulch area outward two to three feet beyond the extend of the tree branch tips. Keep mulch three inches away from the trunk of the tree to prevent any fungal rot on the bark.
Water the tree every day for the first two weeks, providing three inches of water at each event. Decrease this amount to one inch weekly from the third week to the end of the first growing season.
Monitor the growth of the umbrella tree annually, adding water during dry periods to ensure the tree receives one inch of rain or irrigation weekly from spring to autumn. Replenish the mulch each spring or fall to ensure it remains three to four inches deep and extends three feet beyond the branch tips all around the plant.