Amaltas Tree (Cassia fistula): How to Grow and Care for It in Jaipur

In late May, when Jaipur is at its hottest and most trees look worn out, Amaltas (Cassia fistula) does the opposite. It hangs out long chains of yellow flowers, often with few leaves left, and the whole crown turns gold. It is a native Indian tree, it copes with drought once established, and goats leave it alone. It has two weak points: young plants are hurt by frost, and the pulp inside its pods is a laxative.

Photo: Swati Sidhu, CC BY-SA 4.0, via Wikimedia Commons

Quick facts

Scientific name	Cassia fistula L.
Family	Fabaceae (pea family)
Hindi name	अमलतास (Amaltas)
Other names	Golden shower tree, Indian laburnum, Purging cassia, Aragvadha (Sanskrit), Kanikonna (Malayalam), Bahava (Marathi), Garmalo (Gujarati)
Mature height	Usually 8–12 m
Flowers	Bright yellow, in hanging bunches 30–60 cm long
Pods	Dark brown to black, cylindrical, 40–60 cm long
Flowering in north India	About mid-May to mid-June
Water need	Regular for the first 2 summers, low once established
Best planting months in Jaipur	July to August (monsoon)
Jaipur suitability	Good; protect young plants from frost
Conservation status	Least Concern (IUCN Red List)

Why plant Amaltas in Jaipur

Amaltas is one of the most widespread forest trees in India. In the Aravallis it grows wild in scrub forest alongside khair, dhau, ronjh and khejri. ICFRE records that in its natural range the hottest shade temperatures reach 35–47.5 °C and rainfall runs from about 500 mm to more than 3,000 mm. Jaipur averages about 600 mm of rain and has touched 48.5 °C, so the city sits near the hot, dry edge of what the tree is used to, but inside it.

Foresters describe it as "decidedly drought hardy". It grows on poor, shallow soil and on granite and sandstone. ICRAF gives a soil pH range of 5.5 to 8.7, so most of Jaipur's sandy, alkaline ground is fine, as long as water does not stand around the roots.

For Rajasthan there is one big practical advantage. ICFRE notes that Amaltas is "not at all browsed even by goats", and cattle leave it alone too. That is why it survives on grazing land where many other saplings get eaten.

The weak point is cold. Amaltas is not frost-hardy, and frost can kill young seedlings down to ground level, although they usually sprout again from the base. Jaipur's record low is −2.2 °C. A first-year sapling is most at risk on clear, still nights between December and February.

How to plant Amaltas

When to plant

Plant in July or August. In Jaipur the monsoon usually sets in during the last week of June, and July and August are the wettest months. A sapling planted then has the whole rainy season to root before the dry months and its first winter.

Avoid planting from October onwards. A late plant meets frost before it has settled.

Choosing a sapling

For dry areas, ICFRE recommends container plants: seedlings moved into bags in their first rains and planted out in their second rains. So ask the nursery for a polybag sapling about a year old.

To raise your own, collect ripe black pods in March–April. The seed coat is very hard; soaking seed in boiling water for about five minutes gave around 75% germination in one trial, though results vary and some seed waits a year to sprout.

Pit, spacing and protection

• Pit: 45–60 cm each way, refilled with the dug soil mixed with well-rotted farmyard manure. If you hit kankar, break through it.
• Site: full sun. Amaltas tolerates some shade but flowers best in the open. Never plant in a low spot that floods.
• Spacing: 5–6 m apart in a row or along a lane.
• Distance from buildings: the roots are fairly shallow and the tree throws up root suckers, so keep it 4–5 m from walls, paving and pipes.
• Guard: goats and cattle ignore it, but a light guard still protects the stem from trampling, nilgai and people bending it.

First-year watering (practical advice)

Check the soil before you water, and never leave water standing at the base.

Season	How often	Amount
Monsoon (Jul–Sep)	Only after 10 days without rain	10 L
Post-monsoon (Oct–Nov)	Weekly	10–15 L
Winter (Dec–Feb)	Every 2 weeks, mid-morning	10 L
Spring (Mar)	Weekly	15 L
Summer (Apr–Jun)	Every 4–5 days	15–20 L

Care in the first three years

Winter (Dec–Feb): in the first two winters, cover the sapling at night when IMD issues a cold-wave or frost warning. Jute sacking or a straw hood on three sticks, open on the south side, is enough; take it off in the morning. If the top does get burnt, don't pull the plant out. Frost-hit Amaltas seedlings often sprout again from the base, so wait until March and keep the strongest new shoot.

Summer (Apr–Jun): this is the real test in year 1. Water every 4–5 days, early morning or evening, and keep 8–10 cm of dry grass or leaf mulch on the basin, clear of the stem. In year 2, water every 10–14 days. By year 3, water only in a long dry spell.

Monsoon (Jul–Sep): weed the basin twice in year 1 and make sure rainwater drains away.

Pests: ICRAF notes that Amaltas is very susceptible to scale insects and fungi. Scrape scale off young stems by hand. Green caterpillars on the leaves are usually the common emigrant butterfly; a healthy tree regrows, so there is no need to spray.

Pruning: in year 2 or 3, remove low side branches to lift the crown, and cut out root suckers if you want a single tree.

Patience: a young Amaltas can take several years to flower well. We found no reliable figure for the age of first flowering.

Benefits of Amaltas

Colour in the hottest weeks

In north India the tree flowers from about mid-May to mid-June, sometimes later. In full bloom it can look like it is all flowers and no leaves, which is why it is planted so widely as an ornamental.

Bees, butterflies and wildlife

Bees collect pollen from the flowers and nectar from small glands at the base of the leaf stalks. The leaves feed caterpillars of the common emigrant butterfly, and monkeys, birds and jackals eat the sweet pulp of the pods, spreading the seeds.

Light shade, little water

The crown is open, so the shade is dappled rather than dense: good for a courtyard, a park edge or a lane. Once the tree has come through two or three summers, it needs little watering.

Wood and bark

The reddish wood is hard, heavy and durable, and has been used for posts, farm tools and wheels; the bark was used for tanning. GreenEye's gift trees are planted to stand, not to be cut.

Traditional and cultural meaning

In Sanskrit, Amaltas is Aragvadha, often translated as "disease killer". It is an old Ayurvedic plant, also used in Unani and folk medicine. The sweet black pulp around the seeds is best known as a laxative, and the root, bark, leaves and flowers all appear in traditional remedies. This is traditional use only, not medical advice.

In Kerala the flower is Kanikonna, the state flower. On Vishu, the Malayalam new year in April, families arrange the Vishu Kani: rice, coconut, golden cucumber, coins, a lamp and Kanikonna flowers set out in a brass vessel. It is the first thing the family looks at on Vishu morning, for a good year ahead.

Cautions and safety

• The pod pulp is a laxative. ICRAF and Flowers of India call it a mild laxative, but it is also listed as a purgative, and ICRAF records that the seeds are considered emetic (they can cause vomiting). Don't let children chew the sticky pulp of fallen pods, and keep pets away from it.
• Don't self-medicate. Laboratory studies on rats and mice found low acute toxicity for pod and seed extracts, but that does not make home remedies safe. Unani medicine even lists the fruit as abortifacient. Anyone thinking of using Amaltas, especially for a child or during pregnancy, should ask a qualified doctor first.
• Frost is the main risk for young trees in Jaipur. Cover them in the first two winters.
• Shallow roots and suckers: keep the tree away from foundations, and remove suckers that come up in paving.
• Falling pods: ripe pods fall from about May. Near parking or a footpath, someone will need to clear them.

---

Plant a tree in someone's name with GreenEye: Gift a Tree