The Rebloom Confidence Score represents the likelihood that a given cultivar will rebloom, based on documented performance across USDA zones and verified observations at Amethyst Creek Farm (Zone 7b). This proprietary scoring system is informed by both horticultural research and field data. It utilizes a zone-based algorithm to evaluate reported rebloom activity and project probable rebloom success across a wider range of climates. We've used a star rating to easily display the likelihood of reblooming down to Zone 4. 

 

 

⭐⭐⭐⭐⭐— Exceptional Rebloom Potential
Cultivars with a 5-star Rebloom Confidence Score have demonstrated consistent rebloom performance in colder regions, including USDA Zone 4 or below, or have been reliably observed reblooming at Amethyst Creek Farm (Zone 7b). These varieties are considered highly adaptable and are expected to rebloom across a broad range of climates, from Zone 4 through Zone 10, given proper care and growing conditions.

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⭐⭐⭐⭐ — High Rebloom Likelihood

These cultivars are confirmed rebloomers in USDA Zone 5 or similar climates. While not yet proven in the coldest zones, they are generally dependable in Zones 5 through 9 and may perform in Zone 4 with favorable conditions. These irises are well-suited for gardeners in temperate to moderately cold regions.

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⭐⭐⭐ — Moderate Rebloom Likelihood

A 3-star score indicates rebloom activity has been observed in USDA Zone 6 or warmer, but with limited consistency or geographic range. These cultivars are expected to rebloom in Zones 6–9, though performance may vary based on climate, soil, and care.

⭐⭐ — Limited Rebloom Zone Compatibility

Cultivars with this score have only been reported to rebloom in warmer zones (Zone 7 and above), and may not perform reliably in cooler climates. Reblooming may depend on supplemental watering, fertilization, and extended warm seasons.

⭐ — Unconfirmed or Anecdotal Rebloom Reports

These cultivars have been labeled as potential rebloomers without confirmed USDA zone data. Reports are anecdotal or unverified, and performance may be inconsistent. Gardeners should consider these experimental for reblooming purposes.

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— Not a Rebloomer (0 Stars)

These cultivars have no confirmed history of reblooming and are not expected to produce a second bloom cycle. They are valued for their primary bloom performance but are not suitable for gardeners seeking reblooming characteristics. These varieties typically bloom once per season and perform best with standard iris care.