Scientific name: Crescentia cujete

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

Observations:

Phenological Markers – Calabash Tree (Crescentia cujete)

1. Flowering
The Calabash Tree produces greenish-yellow to purplish, bell-shaped flowers, often with dark veining and a slightly waxy texture. What makes it especially unique is its cauliflorous habit:

• Flowers grow directly from the trunk and larger branches, not the outer canopy.
• Flowering can occur throughout the year in tropical climates, but it may peak during the late dry to early wet season (March–May) in St. Croix.
• Flowers are bat-pollinated, opening in the late afternoon or early evening and lasting only a day.

Observation Tips:

• Look closely at the trunk and main limbs for buds and blossoms.
• Record time of day flowers appear and wither.
• Observe and note any pollinator activity at dusk or dawn.

2. Fruiting
After flowering, the tree develops large, round, hard-shelled fruits (gourds), often 6–10 inches in diameter.

• Fruits develop slowly and may remain on the tree for 6–9 months before maturing.
• The hard shells are green when immature, becoming brownish and woody as they ripen.
• Fruits do not split open; instead, they are dispersed by gravity or harvested by humans for use in utensils, crafts, or containers.

Observation Tips:

• Track fruit size, surface texture, and color over time.
• Note hanging duration—some trees carry fruit almost year-round.
• Fallen gourds may remain intact for weeks and are slow to decompose.

3. Leaf Behavior
Leaves are simple, oblong, and bright green, often arranged in small clusters along branches.

• The Calabash Tree is semi-deciduous, sometimes shedding older leaves during the dry season.
• Leaf flushes follow flowering and fruit set, with young leaves appearing more delicate and lighter in color.

Observation Tips:

• Document leaf drop in late dry season, especially during flowering.
• Note new growth around the time of fruit development or early rains.

4. Seasonal Pattern (St. Croix)

• Jan–Mar: Occasional leaf drop
• Mar–May: Peak flowering
• Apr–Jul: New leaf flush + early fruit formation
• Jul–Dec: Fruit development and hanging phase
• Year-round: Sporadic flowering and fruiting may occur in mature trees