How we rate a palm

The Ptolemy condition scale

There is no widely used, detailed standard for rating an individual palm's condition. Most care calls a palm healthy or unhealthy and stops there. We grade two things separately, Color and Fullness, each on a percent basis, and the lower of the two sets the grade. Every palm on Standard or Advanced care is rated the same way, on five tiers from Normal to Dead.

A healthy date palm with a full canopy, graded Normal (80% and above) — **Normal**80% and above

A palm with mild yellowing, illustrative of a Fair grade — **Fair**60 to 79%

A Sylvester palm clearly compromised by nutrient decline, illustrative of a Poor grade — **Poor**40 to 59%

A newly installed royal palm in severe decline, with a thin trunk, few fronds and no full canopy, illustrative of a Critical grade — **Critical**1 to 39%

A palm with a collapsed, dead canopy, illustrative of a Dead grade — **Dead**0%

The five tiers

Normal is the goal, not a perfect score

The basis is percent of canopy. Normal is the goal state at 80 percent and above, a deliberate target: pushing higher adds cost for diminishing visible gain. Good and Excellent are not used.

Dead

Critical

Poor

Fair

Normal

Normal, the goal: 80%

Dead

Non-viable, no active growth.

Critical

1 to 39%

Severe decline.

Poor

40 to 59%

Clearly compromised.

Fair

60 to 79%

Below Normal, recovering or mildly stressed.

Normal

80%+

Doing what a palm should.

Photographs are illustrative of each band, not exact measurements.

Two axes, take the lowest

A palm can hold deep green color but have lost most of its canopy, or be full but badly discolored. So we grade two things independently and let the worse one govern, because the limiting factor is what the palm is actually contending with.

Axis 1 · Color

The percent of the canopy free from chlorosis (yellowing), necrosis (dead tissue), and undersized foliage. Scored on percent green, functional canopy. Old, lower-frond discoloration (potassium, magnesium) routes here.

Axis 2 · Fullness

How much living canopy the palm carries, the size of its new fronds, and whether new growth forms normally. A composite of three sub-factors, scored take-the-worst. Thin canopies and deformed new growth route here.

Overall grade=the lower of Color and Fullness. Good color cannot offset a lost canopy.

Fullness is three things, not one

Rate each sub-factor on the same five tiers, and the Fullness grade is the worst of the three. This is where thin canopies, undersized fronds, and deformed new growth get captured.

Sub-factor 1

Density

The percent of a full canopy present, judged against that palm's own potential, not a fixed frond count. As a canopy thins, the lowest living fronds rise from the 9-and-3 line toward 11-and-1. The angle is a cue, not the verdict.

Sub-factor 2

Frond size

Undersized, stunted new fronds on a palm

Are the newest fronds full length for the species, or stunted? New fronds coming in smaller than the last generation, the narrowing or pencil-pointing trend, is a stress signal judged against the species norm.

Sub-factor 3

New-growth integrity

Severe manganese deficiency (frizzletop) deforming the new central growth of a queen palm

Is the spear and newest growth forming normally, or deformed? Frizzletop (manganese), hookleaf or a fused spear (boron), or a stalled spear. A stalled or dead spear is terminal regardless of the rest of the canopy.

The principle that keeps the axes clean

Where a symptom appears tells you which axis it belongs to. A thin or missing canopy routes to Fullness. Discoloration on the old, lower fronds routes to Color. Small, deformed, or unopened new growth routes to Fullness. No symptom is counted twice.

The lowest-of rule, in action

Color Normal (deep green), Fullness Critical (canopy down to roughly 15%) → overall Critical. Good color cannot offset a lost canopy.

Color Normal, density Normal, new-growth integrity Poor (deformed spear) → Fullness is Poor, so overall Poor.

The watchlist overlay

A palm can grade Normal and still be watched.

After the two-axis grade, we run a watchlist check for a sign, a structural concern, or a declining trend.

What puts a palm on the watchlist

A Ganoderma conk
Lethal bronzing indicators
Palmetto weevil signs
Stem cracks or char
A grade dropping visit over visit

Flagged in our GIS
The palm is marked on the map by its tree number.
Re-checked on a set cadence
It is looked at again on schedule, not when someone happens to notice.
Photo-documented on Standard and Advanced
On the Standard and Advanced levels, every palm is photographed every visit, so the trend is visible. Monitor is a visual inspection, with photos where they help.
Judged on the trend
What turns a grade into a plan is the cause, the trend across visits, and any watchlist sign.

Grade, tier and target

Three different things. One scale grades every palm.

The grade

The palm's condition

Normal, Fair, Poor, Critical or Dead, from the lower of Color and Fullness.

The tier

The work performed

Monitor, Standard or Advanced. Compare the tiers.

The target

The goal set with the client

80 percent (Normal) is our default. Some clients set a higher target of 90 percent and pay for it. A target is a management target, never a guarantee.

The grade is a snapshot, not an action.

A grade carries no automatic response. An over-pruned palm can read Critical and need only the program it is already on. A palm can read Normal and be terminal because of a Ganoderma conk.

Method and sources

The proportion (live-frond-ratio) method draws on palm visual-health research (Blair et al. 2019) and the percent-crown-missing method in the broader arborist standard (i-Tree). New-growth diagnostics follow UF/IFAS (Broschat, EP264 Boron and EP267 Manganese). The five-tier scale is Ptolemy's written condition standard. The numeric cuts are a license-bound judgment signed by an ISA Certified Arborist. See our resources and references.

Three steps to a plan. You are on step 2.

Your next step

Next: where the grade goesThe Health Program: Monitor, Standard, Advanced

The grade tells us where a palm stands. The tier is the work it gets.

Go there →

OrThe floorMonitor in detail Plans and budgetsThe budget-season calendar

Start with the free master plan

See the palms on your property rated this way.

Our trained field team maps and grades every palm. An ISA Certified Arborist reviews the findings and writes one plan for 10 years.

Request the free master plan

Print the board budget brief Call (239) 467-0142