Germination temperature
Warm conditions; the tree is not frost hardy.
Visit deodar-seeds.in Tree growing guide
Golden shower tree, also called Indian laburnum or amaltas, carries long hanging chains of yellow flowers. Its hard-coated seed sprouts within days once nicked or soaked; the seeds are poisonous, so handle them with care.
Warm conditions; the tree is not frost hardy.
Shallow: cover with about the seed's own thickness of soil.
Treated seed starts to emerge from about day 3.
Full sun for growing trees.
Needed: nick and soak 24 hours, or hot-water treat.
Raise in a nursery bed or bags, then plant out.
The seeds are flat, light brown and glossy, packed in pods 40-60 cm long that hold 25-100 seeds each. Remove the pulp, wash and dry them. Keep seeds away from children and pets: they are poisonous.
Recommended. The hard seed coat keeps water out. Nick or file a small spot on the edge of each seed until the paler layer shows. As an alternative, the Tropical Tree Seed Manual places seed in boiling water for 5 minutes before sowing.
Not needed. Dormancy is caused by the hard coat, not by a need for cold.
Soak in room-temperature water for 24 hours before sowing, as TNAU does in forestry nurseries; this gave about 70% germination. Seeds that have swelled are ready; nick and re-soak any that stay hard.
Sow in warm weather. The tree grows naturally where mean annual temperatures are about 18-28.5 °C (64-83 °F) and is not frost hardy, so in cooler countries sow indoors in warmth.
Sow shallow and cover with a thin layer of soil or mix, about the thickness of the seed.
A well-drained nursery mix. The tree tolerates sand, loam or clay and acid to alkaline soils (about pH 5.5-8.7), but seedlings rot in waterlogged mix.
Keep evenly moist until seedlings appear, then water when the surface starts to dry.
Light is not needed for germination. Give seedlings bright light; the tree is moderately shade tolerant but flowers best in full sun.
Soaked or scarified seed begins to emerge from about day 3. Untreated seed can take much longer and comes up unevenly.
TNAU sows treated seed in a nursery bed and moves seedlings into 30 x 45 cm (12 x 18 in) bags. Plant out at the start of the rains, before roots coil in the bag.
Growth can be fast: in large bags seedlings reach about 1.8 m (6 ft) in six months. Stake a young tree if it leans and prune lightly to build a single, strong leader.
Cause: the hard seed coat was not broken, or the seed is old. Fix: nick and soak again; sow fresh seed, as it may lose viability after about a year at room temperature.
Cause: root rot in wet, poorly drained mix. Fix: use a free-draining mix and let the surface dry slightly between waterings.
Cause: leaf spot or mildew, worse in humid, crowded nurseries. Fix: space plants for airflow and remove badly affected leaves.
Cause: caterpillars, an occasional pest. Fix: pick them off; established trees recover quickly.
Full sun and room to spread: the tree grows 9-12 m (30-40 ft) tall and wide. It suits frost-free climates only.
Water young trees through dry spells. Established trees are moderately drought tolerant and grow in areas with 480-2,720 mm of rain a year.
The 30-60 cm (1-2 ft) pods hang on through winter and then fall; avoid planting over patios and parking.
In Tamil Nadu pods are collected in March-April. Store the cleaned seed dry in a sealed container in a cool place.
Nick and soak the seeds, then sow them warm for a golden shower tree.
Break the hard seed coat: nick each seed and soak it for 24 hours, or put it in boiling water for 5 minutes. Treated seed starts to come up from about day 3.
Yes. Do not eat the seeds and keep them away from children and pets.
Cassia siamea is now classified as Senna siamea, a different genus. Like golden shower it is a tropical legume tree with hard seed, but check its own product page for details.