Scientific name: Thespesia grandiflora

GPS Location: 17° 42′ 56.76″ N, 64° 49′ 43.01″ W

Observations:

Phenological Markers – Puerto Rican Hibiscus Tree (Thespesia grandiflora)

1. Flowering
The Puerto Rican Hibiscus produces large, showy flowers—typically pink to purplish-lavender, with a dark maroon throat.

• In St. Croix’s tropical climate, Thespesia grandiflora may flower intermittently year-round, with increased flowering during the early wet season (April to July).
• Flowers open in the morning and may fade slightly by late afternoon, but usually last for a full day.
• Flowering tends to be heaviest following leaf flush, especially after rainfall or pruning.

Observation Tips:

• Record first bud appearance, flower opening, and duration.
• Monitor pollinator activity, especially bees and butterflies.
• Note whether flowering occurs solitarily or in bursts.

2. Fruiting
Fruits develop as rounded, five-lobed capsules, each containing multiple seeds.

• Capsules mature over several weeks, drying to a brownish, woody texture before splitting open.
• Fruiting is sporadic but may follow a major flowering period in mid to late wet season (June–September).

Observation Tips:

• Track capsule formation and ripening stage.
• Watch for seed release and accumulation beneath the canopy.
• Photograph opened vs. unopened capsules to show maturity progression.

3. Leaf Behavior
The tree is evergreen in tropical conditions, with only minor leaf turnover year-round.

• New leaf flushes are typically triggered by flowering or pruning.
• Leaves are oval to heart-shaped, glossy, and medium green when mature.

Observation Tips:

• Look for lighter green flushes near flowering zones.
• Minimal seasonal leaf drop means leaf behavior may be a weak phenological indicator, but flush after rains or stress recovery is notable.

4. Seasonal Pattern (St. Croix)

• Dry to early wet season (Mar–Jun): Peak flowering
• Mid wet season (Jul–Sep): Fruiting, capsule maturity
• Late wet season (Oct–Nov): Minor leaf flush or regrowth if pruned