How to Grow and Care for Golden Chain Tree

Commonly called laburnum, the golden chain tree (Laburnum x watereri) is sometimes confused for the similarly named, similarly-looking golden rain tree. Golden chain tree is a stunning beauty that blooms with fragrant golden-yellow, 10- to 20-inch floral sprigs in late spring. Unlike the other similar-sounding tree, it is not an invasive species. Its leaves are made of three leaflets that look like pointy clover leaves. It prefers to grow in full sun, in moderately moist, well-draining, enriched soil in a moderate climate. All parts of the tree contain cytisine, a toxic substance to humans and pets.

Golden Chain Tree Care

Here are the main care requirements for growing a golden chain tree:

• Plant in fall or early spring; they grow at a moderate pace.
• Grow it in USDA zone 5 through 7; it prefers mild temperatures.
• Stake young specimens, as the trunks are quite floppy.
• Locate it where it can get full sun; in hotter zones, ensure it has some shade.
  
• Give it water only when it's dry; it's fairly drought resistant and susceptible to root rot when standing in overly wet soil.

Light

If you live in a more moderate climate, pick a spot with full sun to plant your golden chain tree. Choose a site with partial shade in warmer temperatures since your tree will get too hot in full sun.

Soil

Golden chain tree grows well in most soil types. Ideally, the soil should have a high content of organic matter. Good drainage is crucial, but in terms of soil acidity, the tree adapts to various pHs, from slightly alkaline to slightly acidic.

Water

The tree has medium moisture requirements, and it is relatively drought-tolerant. Be sure the water doesn't puddle at the base since it doesn't do well in standing water and is particularly susceptible to root rot.

Fertilizer

Apply fertilizer in early spring (one designed for flowering trees and shrubs, with a high acid content). For the amount to use, follow the product label instructions.

Temperature and Humidity

Golden chain trees prefer moderate climates, not too hot or too cold. Even though they can grow in hardiness zone 7, young trees may not survive the climate's heat.

Golden Chain Tree Varieties

There are only two species in the genus Laburnum, common laburnum (Laburnum anagyroides) and alpine laburnum (Laburnum alpinum), native to southern Europe. What is commonly referred to as the golden chain tree in the United States is Laburnum x watereri, a cross between the two species that is considered a superior tree for landscaping than either parent.

There are three notable cultivars of the golden chain tree:

• Laburnum anagyroides 'Sunspire,' a dwarf variety growing 12 ft. tall and 6 ft. wide
• Laburnum anagyroides 'Yellow Rocket,' a trademarked cultivar with a columnar, narrow growth habit that makes it suitable for smaller spaces
• Laburnum × watereri 'Vossii,' a cultivar that produces fewer pods and fewer seeds than other types
  

Pruning

Pruning is required to develop a strong structure. It should be pruned to grow with a single leader. On older specimens, it's normal for the bark to turn dark and fissured. You can also prune the lower branches since they will droop down and get in the way.

The seed pods can be removed as they appear; they aren't particularly attractive and take energy away from the rest of the tree.

Propagating Golden Chain Tree

Unless it is the trademarked 'Yellow Rocket' cultivar, you can propagate the golden chain tree from root cuttings, hardwood cuttings, or whip-grafting. Propagation from hardwood cuttings is the easiest for home gardeners. Here is how it's done:

1. In the fall, choose a strong stem and cut 8 to 10 inches off it with a sharp knife, including at least a few nodes.
2. Remove leaves from the lower third. Dip the stem in rooting hormone. Plant the cutting in a 4-inch pot filled with a damp potting mix.
3. Overwinter the cutting in a protected location outdoors, such as a cold frame. Keep the soil moist at all times.
4. New shoots will appear in the spring if the cutting has rooted. Leave plants in the pot for at least another year until you have a strong sapling.

Growing From Seed

All the commonly grown golden chain trees are cultivars or a cross-breed. Starting them from seed won't produce a tree true to the parent and is therefore not recommended.

Potting and Repotting Golden Chain Tree

The smaller varieties of golden chain trees can be grown in containers. The container needs to be heavy enough, so it does not topple over. For adequate drainage, it should have large drain holes.

Once the tree outgrows its container, repot it in a container one size up from the original pot.

Overwintering

Laburnums are susceptible to sunscald, which happens when nighttime temperatures drop after warm days. The cold damages trees with thin bark. To protect it, wrap the trunk with tree wrap before the onset of winter.

Common Pests and Plant Diseases

Blight, canker, and leaf spot are potential diseases to keep an eye out for. Aphids and mealybugs may also be attracted to the tree; various methods exist to control them, including applying insecticidal soap and horticultural oils.

How to Get Golden Chain Tree to Bloom

How this tree blooms depends on the temperature and climate. A late frost in spring may ruin the blooms and shorten their display, and temperatures that are too warm can also shorten the blooming period.

Bloom Months

Golden chain tree blooms at the end of spring from mid-May to June.

How Long Does Golden Chain Tree Bloom?

The tree blooms for two to three weeks, usually longer if the temperatures are more moderate. This tree does not like heat.

What Do Golden Chain Trees Flowers Look and Smell Like?

Golden chain tree racemes look and smell a lot like sweet-smelling wisteria. The floral sprigs of pea-like blossoms fall in a weeping, pendulous way.

How to Encourage More Blooms

Remove the seed pods in winter to promote flowers in the spring. Fertilize the tree once in the spring with balanced, granular 10-10-10 fertilizer. Prune the weeping golden chain tree in winter with sharp, sterilized tools to encourage vigorous growth, including blooms. Never prune more than one-third of a tree's size in one season.

Caring for Golden Chain Tree After It Blooms

You can prune this tree after it blooms. Since it's entering the hot summer season after blooming, ensure it has sufficient water—at least water it once a week, more during the dog days of summer.

Common Problems With Golden Chain Tree

Because of its plentiful (toxic) seeds, leaves, and flowers, the golden chain tree is also considered messy when its flowers fade.