Phenological Markers

1. Reduced Growth / Dry-Season Rest

What to look for:

• Little or no extension of new shoots
• Mature foliage becoming thinner
• Progressive yellowing of older leaves
• Partial or substantial leaf fall
• Bare branches becoming increasingly visible
• Old seed pods remaining attached

In St. Croix, the degree of leaf loss may vary considerably with rainfall and irrigation.

2. Leaf Senescence

What to look for:

• Leaflets becoming pale green or yellow
• Progressive thinning of the crown
• Individual pinnae dropping
• Entire compound leaves falling
• Increasing visibility of branches through the canopy

Leaf loss may precede peak flowering.

3. Flower-Bud Initiation

Flower buds usually develop near the ends of branches.

What to look for:

• Small clustered buds appearing on mature twigs
• Buds enlarging rapidly
• Green outer surfaces beginning to show reddish or orange tones
• Several buds at different stages in one cluster
• Bud development while the crown is partly leafless

4. Flower-Bud Expansion

What to look for:

• Buds becoming large and rounded
• Petal colour becoming visible before opening
• Flower stalks elongating
• Bud clusters becoming more conspicuous
• Some buds opening while others remain tightly closed

5. Early Flowering

What to look for:

• First open flowers scattered through the canopy
• Red, orange-red, or scarlet petals
• One upper petal often paler or marked with yellow, white, or red
• Flowers appearing prominently against sparse foliage
• Increasing numbers of open flowers each week

6. Peak Flowering

This is the most visually dramatic stage.

What to look for:

• Large portions of the canopy covered with flowers
• Hundreds or thousands of open blossoms
• Reduced visual dominance of foliage
• Fallen petals beneath the tree
• Pollinator activity around the flowers
• Mixture of open flowers and unopened buds

7. Pollinator Activity

What to look for:

• Bees visiting stamens and nectary areas
• Butterflies or other large insects visiting flowers
• Birds investigating blossoms
• Repeated movement between flowers
• Pollen visible on visiting animals

Record visitor species when possible.

8. Flower Senescence

What to look for:

• Petals fading or browning
• Flowers collapsing
• Fallen petals beneath the canopy
• Flower stalks remaining temporarily
• Small ovaries persisting after successful pollination

9. Initial Fruit Set

What to look for:

• Small green flattened pods replacing flowers
• Young fruits forming near branch tips
• Rapid elongation after initial set
• Several young pods developing from former flower clusters
• Unsuccessful flowers dropping without fruit formation

10. Young Pod Development

What to look for:

• Bright green flattened pods
• Rapid increase in length
• Pods initially soft and relatively thin
• Long fruits hanging downward or outward
• Multiple pods developing together

Young pods may already become quite conspicuous while some flowers remain on the tree.

11. Pod Expansion

What to look for:

• Pods becoming longer and broader
• Fruit wall thickening
• Green coloration becoming darker
• Pods becoming heavier
• Individual seed positions becoming subtly visible

Mature pods may reach roughly 40–60 cm or more in length.

12. Seed Development

What to look for externally:

• Pods reaching nearly full size
• Pod walls becoming increasingly firm
• Slight swelling corresponding to developing seeds
• Growth slowing
• Colour remaining green before maturity

Internally, the seeds enlarge and harden.

13. Pod Maturation

What to look for:

• Green pods becoming brown
• Pod walls becoming dry and woody
• Mature pods becoming very hard
• Rattling seeds sometimes audible when dry pods are moved
• Pods persisting for long periods on the tree

This persistent fruit stage can overlap with later leaf flush or even the next flowering cycle.

14. Seed Release

What to look for:

• Mature pods splitting or opening
• Seeds falling beneath the tree
• Empty pod valves remaining temporarily
• Fallen intact pods on the ground
• Seedlings appearing nearby after favorable rainfall

Many pods may remain intact for long periods before opening.

15. New Leaf Flush

Following rainfall or the end of a resting period, new vegetative growth begins.

What to look for:

• Pale green shoots emerging from branch tips
• Young compound leaves unfolding
• Leaflets initially soft and lighter in colour
• Rapid increase in canopy density
• New stem extension

16. Leaf Expansion

What to look for:

• Bipinnate leaves becoming fully extended
• Leaflets darkening from pale to medium or dark green
• Canopy becoming dense and feathery
• New branches hardening
• Flowering declining as vegetative growth increases

17. Mature Canopy Stage

What to look for:

• Dense green foliage
• Little new shoot extension
• Mature woody branches
• Old pods still present
• Reduced flowering
• Stable crown structure

Suggested Observation Schedule

Observe at least once each month.

During flowering and early pod development, weekly or biweekly observations are preferable.

Record:

• Date
• Recent rainfall
• Percentage of canopy with leaves
• Leaf yellowing
• Leaf fall
• Flower buds
• First open flowers
• Peak flowering
• Pollinator activity
• Fading flowers
• Initial fruit set
• Green pods
• Brown mature pods
• Pod opening
• Seed fall
• New leaf flush

Suggested Abundance Scale

For flowers and pods:

0 — Absent
1 — Very few
2 — Occasional
3 — Common
4 — Abundant
5 — Peak display

For foliage:

0 — Leafless
1 — Sparse foliage
2 — Partial canopy
3 — Mostly foliated
4 — Full canopy

Probable Phenological Sequence

Leaf senescence → partial or complete leaf fall → flower-bud formation → early flowering → peak flowering → fruit set → green pod development → brown mature pods → seed release → new leaf flush → mature canopy

Several stages may overlap.

Particularly Valuable Garden Observations

For the St. George Village Botanical Garden specimen, I would pay particular attention to:

1. Relationship between leaf loss and flowering
Does the tree become mostly leafless before peak bloom, or do flowers and mature foliage overlap?

2. Flowering response to rainfall
Does flowering begin after a dry period or shortly after rainfall?

3. Pod persistence
How many months do mature brown pods remain attached?

4. Timing of new leaf flush
Does leaf production begin before flowering ends, or only afterward?

5. Repeatability from year to year
Does the tree follow the same sequence annually, or does rainfall substantially shift the timing?

Best Photographic Phenology Sequence

For this species, I would try to capture:

Leafless or sparse crown → flower buds → first flowers → peak bloom → fading flowers → tiny green pods → elongated green pods → brown mature pods → seed release → new leaf flush

That sequence would make an especially strong Phenology Walk page because the transition from an almost bare tree to a brilliant flowering canopy is one of the most dramatic seasonal changes in the Garden.