Cascabela thevetia aka Yellow Oleander

Cascabela thevetia is a medium-growing evergreen shrub or small tree. In cultivation, it typically reaches 4-8 feet (1.2-2.4m) tall with a 4-5 foot (1.2-1.5m) spread. In its native tropical habitat, it can grow much larger, reaching 20-30 feet (6-9m) in height. The plant features willow-like, linear-lanceolate glossy green leaves measuring 6-7 inches (15-18cm) long with distinctive midribs.

Cascabela thevetia is native to the West Indies, Mexico, Central America, and parts of South America, including Colombia. It naturally inhabits seasonally dry tropical biomes within forest, woodland, savanna, and shrubland ecosystems at elevations from sea level to 1,500 meters. The plant has since naturalized in tropical regions worldwide including Texas, Florida, Hawaii, India, Sri Lanka, and parts of China.

Cascabela thevetia thrives in rich, sandy soils with good drainage. It tolerates a range of soil types but performs best in well-draining substrates. The plant prefers neutral to slightly alkaline soil pH. If growing in containers, combine regular potting soil with peat moss or perlite to improve drainage and encourage a healthy root system.

Cascabela thevetia is a tropical plant that thrives in warm temperatures. It is hardy in USDA zones 8-11 but grows best in frost-free areas. In cooler climates (zones 8-9), it should be protected from frost or grown in containers that can be moved indoors during winter. Missouri Botanical Garden recommends overwintering container plants in a cool location around 40°F (4°C) with moderate light and minimal watering.

Cascabela thevetia appreciates moderate to high humidity, reflecting its tropical origins. In dry environments, misting the plant weekly helps maintain appropriate humidity levels. During particularly dry periods or when grown indoors, misting two to three times per week may be beneficial. However, the plant is reasonably adaptable and tolerates lower humidity once established.

Feed Cascabela thevetia during the active growing season, starting after flower buds appear in early spring. A balanced fertilizer applied monthly through summer supports healthy growth and flowering. During fall and winter, the plant enters a rest period and does not require fertilization. Reduce watering during this dormant phase as well.

Yes, Cascabela thevetia produces fragrant flowers. The large, funnel-shaped yellow or apricot blooms emit a delightful sweet fragrance. Missouri Botanical Garden describes the flowers as 'showy, fragrant'. The scent is most noticeable during warm weather when the plant is in active bloom from summer through fall.

Cascabela thevetia blooms from summer through fall in temperate climates, while in tropical regions it can flower year-round. The striking funnel-shaped flowers are typically bright yellow, though apricot and cream-colored varieties exist. Each flower measures about 3 inches (7.5cm) long and appears in few-flowered terminal clusters called cymes. Flowers give way to distinctive black seed pods, each containing 1-2 nut-like seeds.

Cascabela thevetia requires minimal pruning. Deadhead spent blooms promptly to maintain the plant's appearance and prevent seed pod formation. Light pruning after flowering helps maintain shape and encourages bushier growth. When pruning, always wear gloves and protective clothing as the milky sap can cause skin irritation. Avoid burning pruned material as the smoke is also toxic.

Repot container-grown Cascabela thevetia every two to three years, preferably in March just before the start of spring and the active growing season. Use a well-draining potting mix combining regular potting soil with peat moss or perlite. Choose a container with adequate drainage holes and only increase pot size by one size increment to prevent overwatering issues.

Cascabela thevetia is most commonly propagated from stem cuttings taken in late summer. Select semi-hardwood cuttings from healthy growth, remove lower leaves, and plant in well-draining rooting medium. Keep cuttings warm and moist until roots develop. The plant can also be grown from its nut-like seeds, though seedlings may take longer to reach flowering size. Always handle the plant with gloves due to its toxic sap.

Cascabela thevetia has relatively few pest problems. Common issues include mealybugs, aphids, and scale insects, which can be managed with insecticidal soap or horticultural oil. Caterpillars may occasionally chew on foliage. The plant may develop leaf spot in humid conditions. Overall, it is considered a low-maintenance plant with good pest resistance due to its toxic compounds.

Cascabela thevetia is pollinated by insects, primarily bees and butterflies, though birds may also visit the flowers. The fragrant, tubular flowers have a specialized mechanism in their throat that coats visiting insects with pollen as they reach for nectar. This ensures effective pollen transfer to subsequent flowers. In Hawaii, it is documented as a valuable honey bee plant.

Cascabela thevetia has documented traditional medicinal uses, though extreme caution is required due to its high toxicity. Historically, leaves have been used as a cardiotonic and diuretic, while various parts have been applied to treat conditions including amenorrhoea, malarial fever, and skin problems. The cardiac glycosides in the plant are being researched for potential anticancer properties. However, due to its extreme toxicity, any medicinal use requires expert supervision and is not recommended for home use.

Beyond ornamental use, Cascabela thevetia serves several purposes. POWO documents uses including animal feed, fuel, materials, and social applications. The plant is widely grown as an ornamental for its attractive flowers and used for hedging and screening in tropical landscapes. Seeds have historically been used as a source of poison and rodenticide. The name 'Lucky Nut' comes from the Caribbean tradition of carrying the seeds as good luck charms.

Cascabela thevetia requires different care through the seasons. During spring and summer (active growth), provide regular watering, keeping soil consistently moist during flowering to prevent early flower wilting. Feed monthly with balanced fertilizer. In fall, reduce watering and stop fertilizing as growth slows. In winter, the plant enters dormancy—water infrequently and keep in a cool location (around 40°F/4°C) if overwintering indoors.

Cascabela thevetia is primarily grown in its typical yellow-flowered form, though some color variations exist. Apricot, cream, and orange-flowered forms are occasionally available in cultivation. The flower color may vary from a clear, satiny yellow to deeper apricot tones depending on the individual plant and growing conditions. All color forms share the same care requirements and toxicity concerns.