Siamese Cassia (Senna siamea)

Siamese Cassia

Senna siamea

Golden blooms cascade like sunlit waterfalls, a tropical street tree with feathery foliage. Deciduous flowering tree; common names: Siamese cassia, Kassod tree.

Full sun
2–3/week
Moderate
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Plant Needs

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Sunlight Requires full sun for abundant flowering; tolerates partial shade but may produce fewer blooms
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Watering Water deeply when the top 5–10 cm of soil dries out; avoid overwatering to prevent root rot
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Temperature Thrives in warm tropical to subtropical temperatures; protect from frost below 10°C to prevent leaf damage
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Characteristics

  • Leaf: Pinnately compound, 15–30 cm long; 6–12 pairs of oblong, glossy green leaflets
  • Flower: Bright yellow, fragrant, clustered in terminal racemes; 5 rounded petals per bloom
  • Stem/Bark: Smooth gray-brown bark when young; becomes fissured and rough with age
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Horticulturist's Insider Field Notes (No AI Fluff)

The Golden 'Finger Test' Rule

Never water on a strict calendar. Stick your index finger 2 inches into the soil. If it feels cool and damp, wait 2–3 days. If bone dry, water thoroughly until it drains from the bottom holes.

Empty the Saucer After 20 Minutes

The #1 houseplant killer is water sitting in the catch tray. Stagnant runoff water starves roots of oxygen and causes root rot.

Turn the Pot Every 2 Weeks

Houseplants naturally lean toward the nearest window light. Give the pot a quarter-turn biweekly to maintain balanced, symmetrical architecture.

Wipe the Dust Away

Dust on leaves acts like a heavy sunshade. Gently wipe broad foliage with a damp cloth monthly to maximize photosynthesis and air purification.

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Care Guide

Watering

Keep soil consistently moist but not waterlogged; increase frequency during hot, dry spells

Fertilization

Apply balanced slow-release fertilizer once monthly to support new growth. Avoid over-fertilizing to prevent excessive foliage growth at the expense of flowers

Banana peel compost tea:Use fully composted banana peels, dilute 1:25 with water for root drench; avoid raw peels to prevent pest infestations and odor
Pruning
  • Remove dead, diseased, or damaged branches in late winter before new growth emerges
  • Thin overcrowded inner branches to improve airflow and light penetration
  • Prune after flowering to maintain a compact, desired canopy shape
  • Remove suckers growing from the base to prevent unwanted spreading
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Pet & Human Toxicity & Emergency Guide

⚠️ Toxic to Pets (Cats & Dogs)

Toxicity Warning: Veterinary toxicology registers Siamese Cassia (Senna siamea) as possessing biochemical compounds (such as insoluble oxalates, alkaloids, or saponins) that pose ingestion hazards to felines and canines.

Feline Ingestion Risks (Cats)

Oral pain, hypersalivation (excessive drooling), pawing at mouth, swelling of tongue or lips, vocalization, and vomiting.

Canine Ingestion Risks (Dogs)

Oral mucosal irritation, gagging, retching, lack of appetite, lethargy, diarrhea, and difficulty swallowing.

Immediate Emergency First-Aid

Do NOT induce vomiting without veterinary instructions! Carefully remove remaining plant pieces, gently rinse mouth with cool water, and monitor breathing.

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Chewed leaf or stem? Open PlantFun App to scan the plant, immediately verify the botanical species, and view ASPCA toxicity severity ratings & vet first-aid advice.

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Troubleshooting & Common Plant Problems

Quick diagnostic guide for common care issues affecting Siamese Cassia (Senna siamea):

Yellowing Leaves

Most commonly caused by overwatering or poor drainage. Ensure topsoil dries out between waterings and check for root ventilation.

Brown or Crispy Leaf Tips

Low ambient humidity, hard tap water minerals, or direct midday sunburn. Increase humidity and use filtered water.

Drooping or Wilting Foliage

Indicates dehydration or root damage from prolonged waterlogging. Inspect soil moisture and root firmness.

Common Pests (Spider Mites, Aphids)

Dry indoor air encourages pests. Wipe leaves with a damp cloth and treat with insecticidal soap or neem oil.

🌿 Instant AI Plant Health Check

Take a photo of any leaf on PlantFun App to get instant diagnosis of diseases, pests, and custom care recovery steps.

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Propagation & Repotting Guide

  • Taking Cuttings: During active spring or summer growth, take a healthy 4–6 inch cutting just below a node using clean shears.
  • Rooting Medium: Place cuttings in fresh water or moist perlite mix in bright, indirect light; refresh water weekly.
  • Potting Up: Transplant into well-draining potting mix once roots reach 2 inches in length (typically 3–5 weeks).
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Seasonal Care Calendar

  • Spring & Summer (Active Growth): Water thoroughly as topsoil dries; apply diluted balanced fertilizer monthly; encourage steady growth.
  • Autumn (Transition): Gradually reduce watering frequency as daylight hours shorten; discontinue fertilization.
  • Winter (Dormancy): Water sparingly only when soil is mostly dry; protect from cold window drafts; keep in warm room.
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Frequently Asked Questions

How often should I water my Siamese Cassia?

Water thoroughly when the top 1–2 inches of soil feel dry. In active growth (spring/summer), water every 1–2 weeks; reduce significantly in winter.

Where is the best indoor location for Siamese Cassia?

Position in bright, filtered indirect light (e.g., near an east or south-facing window with sheer curtains). Avoid harsh direct midday sun.

Is Siamese Cassia toxic to pets?

ASPCA: Toxic; contains anthraquinones that cause gastrointestinal distress

When should I repot my Siamese Cassia?

Repot every 1–2 years in spring when roots outgrow the drainage holes or the soil depletes nutrients.

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Garden Uses & Culture

Culture: Used in traditional Southeast Asian medicine for mild laxative properties; planted as a shade and ornamental street tree

Usage: Ornamental landscape tree, nitrogen-fixing soil improver, limited medicinal use (regulated)

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