Phenology Walk – Swartz’s Pigeonplum

Swartz’s Pigeon Plum (Coccoloba swartzii)

Family: Polygonaceae
Origin: Native to the Caribbean, including the Virgin Islands
Garden location: 17° 42′ 58.76 N, 64° 49′ 46.39 W (Back 9)
ArbNet Level II list: Yes
POWO Status: Tree
IUCN Red List threat level: Least Concern

What to watch for (Phenology)

Leaves

  • Leaf flush: Periodic throughout the year, strongest after rainfall
  • Leaf drop: Evergreen to semi-evergreen; gradual turnover
  • Notes: Leaves are leathery, oval to rounded, smaller and firmer than Coccoloba uvifera, with good drought tolerance

Flowers

  • Buds: Form in elongated, slender racemes
  • First bloom: Often late spring into wet season
  • Peak bloom: Wet season
  • End of bloom: Moderate duration
  • Pollinators observed: Bees and small insects
  • Notes: Small, pale flowers — not showy, but important for nectar and fruit set

Fruit / seed

  • Fruit set: After flowering
  • Ripening: Summer into early fall
  • Dispersal: Birds, wildlife, and gravity
  • Notes: Produces small, grape-like fruits similar to sea grape but smaller — an important native wildlife food source

Weather sensitivity

  • Rain-triggered? Flowering and leaf flush increase after rainfall
  • Drought response: High tolerance once established
  • Salt & wind tolerance: Moderate; suitable for coastal woodland and dry forest
  • Other notes: Well adapted to limestone soils and dry Caribbean habitats

Why this plant matters

Coccoloba swartzii is a true native Caribbean dry-forest and coastal woodland tree, quieter and more restrained than its flamboyant cousin Coccoloba uvifera, yet ecologically vital.

Phenologically, it expresses steady, reliable rhythms: persistent foliage, modest flowering, and dependable fruiting that sustains birds and wildlife. It belongs to your “quiet backbone native” guild — species that hold ecosystems together without drawing attention.

It teaches the value of subtlety, endurance, and local belonging.

Cultural, ecological, and historical significance

Ecological value

  • Provides fruit for birds and wildlife
  • Contributes to native dry-forest structure and regeneration
  • Valuable in restoration, habitat planting, and native landscaping

Cultural and regional context

  • Less widely planted than sea grape, but ecologically more representative of native woodland
  • Part of the pre-colonial Virgin Islands forest matrix
  • A strong complement to Coccoloba uvifera and Coccoloba pubescens — forming a native Coccoloba triad

St. Croix / Virgin Islands notes

  • Native to St. Croix dry forest, limestone woodland, and coastal habitats
  • Often overlooked due to modest fruit and foliage, yet highly important for biodiversity and habitat stability
  • A strong candidate for native reforestation and ecological education

My observations

  • First observed in project: (date)
  • Notable moments:
    • (YYYY-MM-DD) — Fresh leaf flush after rainfall
    • (YYYY-MM-DD) — Heavy fruiting attracting birds
  • Questions / uncertainties:
    • Degree of seasonal variation in fruit yield
    • Relative drought resilience compared to C. uvifera

Photos

  • Whole tree / habit
  • Leaves (texture, size, venation)
  • Flower racemes (buds → bloom)
  • Fruit clusters (immature → ripe)
  • Bark and branching
  • Seasonal comparison images across wet vs. dry periods

Why this one strengthens your 100-plant set

  • Adds a true Virgin Islands native Coccoloba
  • Deepens your coastal & dry-forest keystone tree narrative
  • Expands representation of native fruit-bearing wildlife plants
  • Pairs beautifully with Coccoloba uvifera, Coccoloba pubescens, Cordia collococca, and Guapira fragrans in a Caribbean dry-forest guild

Medicinal Uses

Coccoloba swartzii, known as Bois rouge or Tie-tongue, is not widely recognized for medicinal uses, with sources indicating it offers no known medicinal benefits, unlike its relative Coccoloba uvifera (Sea Grape) which has traditional uses for skin issues, diarrhea, and asthma; C. swartzii‘s primary value lies in its hard, durable wood for construction and fence posts. 

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