A fairly cold-hardy citrus plant with small, sweet-and-sour fruits, the kumquat is native to China and has grown in North America since the 1800s. The kumquat is a low shrubby tree, typically 8 to 15 feet tall. The kumquat tree bears fragrant white flowers in the spring that give way to small fruits. Plant kumquat in the late winter or early spring when frost danger has passed.
Select a site that offers your kumquat tree well-draining soil and full sun. Then test the pH using a home pH test kit. Most kits require you to moisten soil and place a pH color change strip on the wet soil, which generates a reading. Kumquats, like most citrus, prefer a pH of 6 to 8.
Amend your soil by adding sulfur to lower the pH or lime to raise it.
Dig a hole for your kumquat tree with a shovel. Make the hole just as deep and twice as wide as the kumquat tree's root ball. Remove any weeds or rocks from the hole.
Pull your kumquat tree out of its container by grasping the tree at the trunk and pulling up. Break apart the root ball with your fingers. Unwind and untangle the plat's roots, since tangled roots can kill the tree by choking off its water supply. Rinse the kumquat's roots under water to remove the soil medium.
Place your kumquat tree in the hole and check to make sure it's vertically straight.
Backfill the hole with soil, but do not compress the soil. Fill in the hole until the tree is securely planted.
Build a watering ring 5 to 6 inches high and 6 to 8 inches thick around the kumquat tree. Mound up the soil near the kumquat tree to create a basin that's 5 to 6 inches tall at the edges, using ground level as the bottom of the basin. Bring soil from other parts of the garden if you need extra soil to build the ring.
Water the newly planted tree by filling in the watering ring you just built to the top. Over time the roots will draw in the water and drain the watering ring. Water the kumquat tree twice more the week of planting by filling this ring, then decrease to once weekly.