- **Type**: Evergreen shrub (in warm climates) or tender perennial (in cooler zones)

- **Height**: 4 to 6 feet (1.2 to 1.8 meters); can reach 9 feet (2.7 meters) in tropical regions if unpruned

- **Width**: 4 to 6 feet (1.2 to 1.8 meters)

- **Growth Habit**: Upright, bushy, with a loose, open structure; can be pruned to a compact mound

- **Foliage**:

- Small, oblong, bluish-gray-green leaves, 1 to 2 inches long (2.5 to 5 cm)

- Glossy texture, evergreen in frost-free areas; may turn bronzy in cooler weather

- **Flowers**:

- Clusters of bright yellow, star-shaped blooms with red centers (stamens and pistil)

- About 0.75 to 1 inch (2 to 2.5 cm) across, in terminal racemes up to 6 inches (15 cm) long

- Bloom season: Spring to fall (April to October) in most climates; year-round in frost-free zones

- Sweetly fragrant (subtle, not overpowering), attracts butterflies, bees, and hummingbirds

- **Fruit**:

- Small, three-lobed capsules, not ornamentally significant

- **Light**: Full sun (6+ hours daily) for best flowering and structure; tolerates partial shade (may get leggy)

- **Soil**:

- Well-drained; adapts to sandy, loamy, or average soils

- Slightly acidic to neutral (pH 5.5 to 7.0)

- **Watering**: Moderate; drought-tolerant once established, water regularly during first year

- **Hardiness**: USDA Zones 9 to 11 (20°F or -6°C; may die back in Zone 9 but regrows from roots)

- **Wildlife**: Attracts pollinators; deer-resistant due to unpalatability

- **Care**:

- Prune in early spring (March) for shape or to encourage denser growth; heavy pruning boosts flowering in cooler climates

- Fertilize lightly with a balanced mix (e.g., 10-10-10) in spring

- Mulch in colder zones (Zone 9) to protect roots over winter

- **Pests/Diseases**:

- Generally pest-free; occasional caterpillars, spider mites, or whiteflies

- Susceptible to root rot in soggy conditions

- **Uses**: Hedge, border, mass planting, container plant, or backdrop for shorter shrubs

- **Growth Rate**: Moderate to fast; can grow 1 to 4 feet in the first season with good conditions

- **Special Features**:

- Long bloom period and low maintenance make it a standout

- Native to Mexico and Central America; used in traditional medicine (e.g., sedative, anti-inflammatory)

- Not considered toxic, but no definitive evidence of edibility

Thryallis’s cheerful yellow blooms and easy-going nature make it a fantastic choice for adding year-round color to sunny subtropical gardens or containers in milder climates. Let me know if you’d like more growing tips or design ideas with it!