Golden chain tree, also known as laburnum, is a small deciduous tree that brightens the landscape with large clusters of bright yellow, chain-like flowers in mid- to late spring. A relatively short-lived tree, golden chain thrives in U.S. Department of Agriculture plant hardiness zones 5 to 7. Propagate a new golden chain tree by stem cuttings, planting seed or by layering.
Golden chain thrives in moist, cool, well-drained soil, and benefits from soil that you've amended with 2 or 3 inches of rotten manure or compost. The best location for golden chain is where the tree receives plenty of morning sunlight, but is protected by shade during the afternoon.
Propagation by Cuttings
To propagate golden chain, take 3- to 5-inch cuttings from a mature tree in late fall or early winter. Place the cuttings in a container filled with a well-drained potting medium. Cover the laburnum cuttings with clear plastic, and then place the container in a warm spot and bright, indirect light. Keep the potting medium lightly moist until the seeds germinate. After that time, remove the plastic and place the container in brighter light. Allow the cuttings to mature at least until the following spring, and then plant the young golden chain trees outdoors.
Propagation by Seed
Harvest laburnum seeds in autumn. Gather the laburnum seeds and store them in the refrigerator until planting time in late summer the following year. At planting time, soak the seeds in warm water for 24 hours, and then plant the seeds directly in the soil. Cover the seeds with about 1/4 inch of soil and keep the soil slightly moist until the seeds germinate. After the laburnum seeds germinate, allow the soil to dry slightly between waterings in order to encourage the development of long, healthy roots.
Propagation by Layering
Layering is an easy way to propagate golden chain any time of year that the branches are flexible and the ground isn't frozen. Locate a long branch near the lower part of the tree. Bend the branch until it touches the soil about 6 to 8 inches from the tip of the branch. At the point where it touches the soil, secure the branch with a heavy rock or a piece of bent wire. After the branch takes root and you can see new growth, sever the branch from the mother plant. Dig up the rooted branch and plant it in a permanent location.