Tree · Sapindaceae
Golden Rain Tree
Koelreuteria paniculata
A sturdy shade tree, glowing at midsummer with loose yellow flower sprays over papery, lantern-shaped pods.
Full sun
Every 7–14 days
USDA 5–9
30–40 ft · 9.1–12.2 m
Overview
In summer the golden rain tree covers itself in loose, open sprays of small yellow flowers, each bloom no bigger than a fingertip, massed until the whole rounded crown glows gold. As the color fades, the flowers give way to papery seed capsules shaped like little Chinese lanterns, three-sided and inflated, that pale from green to tan and rattle with hard seeds inside. This is a deciduous member of the soapberry family, and its leaves are divided into many toothed leaflets that spread wide along each stem.
The plant's whole build reads as tough. Its wood, though somewhat brittle, frames a broad spreading head, the deep roots ride out drought once settled, and the tree takes clay, sand, or thin rocky ground and cold down to -20°F (-29°C). Set in full sun, its divided foliage catches the light across a canopy as wide as it is tall.
The papery lanterns are the tree's tell in more ways than one. They swell with great numbers of hard seeds and split to scatter them so freely that the tree has turned weedy and invasive across parts of the eastern and southeastern US. Where the seedlings become a problem, gathering the fallen capsules before they open is the surest way to cut the flood short.
Care
The short version: full sun, well-drained soil of almost any kind, and a deep drink during long dry spells while the tree is young. After the first year or two it mostly fends for itself, and a light prune in late winter keeps the frame strong.
Light
Set it in full sun for the fullest flowering, though it will take part sun without much complaint. The more direct light reaches the divided leaves, the denser the golden sprays that follow in summer.
Water
Water a young tree regularly through its first year or two while the roots reach down. Once settled it is drought tolerant and wants a drink only during long dry spells, so let the top half of the soil dry between waterings.
Soil
Few trees are this easygoing about soil. It grows in clay, loam, sand, and even shallow rocky ground, asking only for decent drainage, and it handles a wide pH from 6.0 to 8.0.
Temperature
This is a cold-hardy tree, at ease from -20°F to 100°F (-29°C to 38°C). That wide range covers many climates, part of why it has spread so far.
Humidity
This tree draws all the moisture it needs from plain open air, so there is no humidity level to chart. Far more telling is the drainage at its roots, which weighs heavier than any dampness drifting around the canopy.
Feeding
This tree asks for almost no feeding. If the canopy thins and growth looks weak, a lone spring helping of balanced slow-release tree fertilizer sets it right, for this hardy tree is a light feeder rather than a hungry one.
Pruning
Prune in late winter while the tree is dormant to build one strong central leader and cut out crossing, weak, or dead branches. The pale wood runs a little brittle, so a sound frame built early pays off later.
Repotting
Planted in the ground, this tree stays put for good, so repotting is a non-issue. In a container, step it up to a bigger pot only when the roots coil tight against the walls, water sluices right through the mix, or the top growth grinds to a halt.
Size & spacing
Give it real room. A mature golden rain tree reaches roughly 30 to 40 feet (9 to 12 m) tall and spreads its wide, rounded head about as far, so site it well clear of buildings and overhead lines.
When to plant
This is a tree measured in years rather than a planting date to chase. Set it out in spring after the last frost or in fall, watch the yellow flower sprays open across the crown in early to midsummer, and follow them with the swelling lantern pods that carry the show toward autumn.
Northern hemisphere
Southern hemisphere
Typical months for a temperate climate: start earlier in warm zones, later where spring frosts linger.
- Sow: Late winter, after seed scarification and cold-moist stratification
- Plant: Spring after last frost, or fall
- Harvest: Summer (June to July; cultivar 'September' blooms August to September)
Hardiness
USDA hardiness zones: 5–9
Temperature: down to -29°C
Troubleshooting
A healthy golden rain tree shows few faults. What does surface is usually a wilt disease streaking the wood or a harmless swarm of bright bugs crowding the seed pods. Match what you see below and act while the tree still holds its vigor.
One flank drooping, dark streaks threading the pale wood
When the leaves droop and die back on one side of the tree and a cut reveals dark streaks running through the pale sapwood, that is the mark of verticillium wilt, a soilborne fungus with no cure. Canker and coral spot fungi settle into wood already stressed or wounded, and soil that stays soaked brings on root rot at the base. Prune well below the streaked wood, wipe the blade clean between cuts, and open up the drainage so the tree holds its strength.
Fix:
- Prune out and destroy affected branches well below symptoms, disinfecting tools between cuts
- Improve drainage and avoid drought and mechanical wounding to reduce stress
- Remove severely declining trees, as there is no cure for verticillium wilt
Bright red-and-black bugs clustered over the papery lanterns
The small insects clustered in bold red and black across the papery pods and bark are the goldenrain tree bug, a boxelder relative that feeds on the seeds inside the lanterns. Their crowds look dramatic but amount to a nuisance rather than a real threat, so they can be left in place or rinsed off with a hard stream of water or insecticidal soap. Clearing the fallen capsules strips away the seed they feed on, and a horticultural oil coats and clears any scale crusting the twigs.
Fix:
- Tolerate the bugs where possible, as they are a nuisance rather than a serious threat to tree health
- Knock bugs off or spray congregations with a strong stream of water or insecticidal soap
- Treat heavy scale infestations with horticultural oil
Toxicity
Good news for households with pets and children: this tree is not poisonous. For all the drama in its name, golden rain tree carries no toxin and does not appear on ASPCA toxic-plant lists. Take care only not to confuse it with the genuinely poisonous golden chain tree, Laburnum, a different plant altogether.
Safe for
People · Cats · Dogs · Horses · Rabbits · Livestock · Birds
Cats Safe
A cat can nose through the divided leaves or mouth a fallen lantern pod without harm, as the tree carries no toxin that affects them. One that gulps down a wad of foliage may bring up a hairball or green scraps, which is ordinary rather than poisoning.
Dogs Safe
No toxin in the leaves, twigs, or papery capsules makes this tree a danger to dogs. A dog that crunches a dry pod may pass loose stools from the crackly husk and hard seed, an effect that clears with water on hand.
Horses Safe
Horses can crop grass beneath the spreading crown without concern, since the tree holds no toxin that affects them. It is the harmless cousin of the dangerous golden chain tree, so the worry tied to Laburnum has no footing here.
Rabbits Safe
The compound leaves carry no poisoning risk for rabbits. As with any fresh green, a small first helping lets a sensitive gut adjust before more.
Livestock Safe
Cattle, goats, and sheep can graze around this tree safely, as it is not toxic to grazing animals. Stripping too much foliage from any one plant can turn a stomach, but that is overeating rather than poisoning.
Birds Safe
The foliage and the seeds hidden in the papery lanterns pose no toxic threat to birds, and many pass the dry pods by. Backyard poultry can scratch through the leaf litter under the canopy without trouble.
People Safe
This tree is not poisonous to people, and its common name stirs more alarm than the plant ever earns. Even so, the small dark seeds inside the lanterns are grown for looks rather than the plate, so there is no reason to eat them.
No special handling required; as with any plant, discourage pets and children from chewing on foliage or seed pods to avoid mild stomach upset.
Varieties
Only a few selections turn up in the trade, and one close relative often sells beside the species. These are the ones worth telling apart by leaf and pod.
'September'
This selection withholds its sprays of yellow flowers until August and September, stretching the bloom weeks past the usual summer show, though it trades away a little winter hardiness in the trade.
Koelreuteria bipinnata (Chinese flame tree)
A close relative whose leaves are twice-divided into finer leaflets and whose lantern pods flush a showy rosy pink, it runs more tender and belongs to warmer zones than the golden rain tree.
How to propagate
Your first golden rain tree will likely arrive as a self-sown seedling sprung from a fallen lantern, since this tree multiplies with no help at all. To raise more on purpose, you can start from seed or take root cuttings.
SeedModerate
Sow in fall outdoors, or stratify and sow in late winter to early spring · Seedlings appear in weeks; several years to a sizable tree
Each papery lantern holds hard, round seeds, and the tree drops them by the bucketful, self-sowing so freely that starting it on purpose is rarely necessary. To raise it deliberately, scratch through the hard seed coat and give the seed a spell of cold, moist stratification, sowing outdoors in fall or in late winter to early spring. Slim seedlings push up within weeks, but expect several years before you have a tree of any size.
Stem cuttingsModerate
Dormant season for root cuttings · One to two growing seasons
Root cuttings lifted in the dormant season are the usual way to clone this tree, and named cultivars are grown from these rather than from seed so the offspring come true. A rooted cutting takes one to two growing seasons to settle before it puts on much top growth.
Myths
Golden rain tree and the toxic golden chain tree are the very same plant, deadly to pets.
The two share little beyond a similar name. Golden rain tree sits in the soapberry family and stays off the ASPCA toxic-plant lists, while the genuinely poisonous golden chain tree is Laburnum, an unrelated legume. Read the botanical name, Koelreuteria paniculata, and this is a tree you can plant without worry.