Common Name | Golden chain tree, bean tree, laburnum |
Botanical Name | Laburnum anagyroides, Laburnum x watereri |
Family | Fabaceae |
Plant Type | Tree |
Mature Size | 15-30 ft. tall and wide |
Sun Exposure | Full |
Soil Type | Well-drained, moist |
Soil pH | Acidic, neutral, alkaline |
Bloom Time | Spring |
Flower Color | Yellow |
Hardiness Zones | 5-7 (USDA) |
Native Area | Europe |
Toxicity | Toxic to humans, toxic to pets |
Golden Chain Tree Care
Here are the main care requirements for growing a golden chain tree:
- Plant the golden chain tree in the fall or early spring.
- Grow the golden chain tree in a region with mild temperatures.
- Stake young golden chain trees to support floppy trunks.
- Locate the golden chain tree where it can get full sun. In hotter zones, ensure the plant has some shade.
- Give a golden chain tree water only when 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 flourish 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.
Types of Golden Chain Tree
Two species in the genus Laburnum, common laburnum (Laburnum anagyroides) and alpine laburnum (Laburnum alpinum), are 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 to either parent.
There are three notable cultivars of the golden chain tree:
- Laburnum anagyroides ‘Sunspire’: This dwarf variety grows 12 feet tall and 6 feet wide.
- Laburnum anagyroides ‘Yellow Rocket’: A trademarked cultivar with a columnar, narrow growth habit makes this cultivar suitable for smaller spaces.
- Laburnum × watereri ‘Vossii’: This cultivar, which looks like the common laburnum, produces fewer pods and seeds than other types.
Pruning
Pruning is required to develop a strong structure. It should be pruned to grow with a single leader. It’s normal for the bark of older trees to turn dark and fissured. You can also prune the lower branches since they droop and get in the way.
The seed pods are unattractive and can be removed when they appear so they don’t use up the tree’s energy.
Propagating Golden Chain Tree
All the commonly grown golden chain trees are cultivars or cross-bred. Starting them from seed won’t produce a tree true to the parent and is therefore not recommended.
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 and should always be done while wearing protective gloves. Take these steps:
- In the fall, choose a strong stem and cut off 8 to 10 inches with a sharp knife, including at least a few nodes.
- Remove leaves from the lower third of the stem. Dip the stem in rooting hormone. Plant the cutting in a 4-inch pot filled with a damp potting mix.
- Overwinter the cutting in a protected location outdoors, such as a cold frame. Keep the soil moist at all times.
- 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.
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, wear gloves and repot it with fresh potting mix 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
Aphids and mealybugs may also be attracted to the tree; various methods exist to control them, including applying insecticidal soap and horticultural oils.
Blight, canker, and leaf spot are potential diseases to keep an eye out for.
How to Get Golden Chain Tree to Bloom
The way the 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. 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 yellow 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 a third of a tree’s size in one season.
Common Problems With Golden Chain Tree
These trees are fairly hardy once established but they have a few challenges to watch for:
Yellowing and Wilting Leaves
A golden chain tree is easily afflicted by root rot which reveals itself through yellowing of the leaves and an overall wilted appearance. If your tree is showing these signs, check the roots immediately. Healthy roots will be firm and rotting roots will be black and mushy. Avoid overwatering as trees in standing water can quickly develop root rot.
Failure to Bloom
If your tree fails to bloom, it may need more light. Make sure the tree is where it can receive six to eight hours of sun each day. Low temperatures could also result in few or no blooms. These trees do best in climates where both summers and winters are moderate.
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The golden chain tree is toxic to humans and animals, including dogs. All parts of the tree are toxic to touch. Always wear protective gloves and clothing when working with golden chain trees.
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A golden chain tree can grow 15 to 30 feet tall and wide but a dwarf type is available.
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The golden chain tree is often confused with the similarly named, similar-looking but invasive golden rain tree (Koelreuteria paniculata), and the best way to tell the difference is by the differing flowers. Golden chain tree flowers have long racemes that look almost like wisteria. Golden rain trees have flowers that grow in large, looser clusters.
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