Persian Ironwood

Leaf emergence

Parrotia persica

Hamamelidaceae · broadleaf deciduous tree · introduced

Last updated

Data Maturity Structured

This profile synthesizes data from multiple published sources. Expert field review is in progress.

Parrotia persica (Hamamelidaceae) is a deciduous tree or large shrub native to northern Iran and Azerbaijan. It grows 20 to 40 feet tall with a rounded, spreading crown and exfoliating bark that reveals a mosaic of gray, green, white, and brown. Dark red flowers consisting mostly of stamens appear on bare branches in late winter to early spring before the foliage emerges. Fall color is exceptional, ranging through yellow, orange, red, and purple, often with multiple colors on a single tree.

Persian ironwood thrives in full sun to part shade on well-drained soil across a range of soil types. It is notably pest- and disease-free, with no significant problems documented. The species tolerates moderate drought once established. Growth rate is moderate. It is valued as a four-season specimen tree for its winter flowers, summer foliage, fall color, and winter bark display. Hardy in Zones 5a to 8b.

Field Observations

Parrotia persica 'Vanessa' - fall color
Field Observation
Parrotia persica 'Vanessa' · Persian Ironwood
fall color
November 11, 2022 · Issaquah · 6,913 GDD₃₂ · BBCH 93

Quick Facts

Height
20–40 ft
Spread
15–30 ft
Growth Rate
Slow # mbg: typically 10 ft after 7-8 years
Light
Sun to Part Shade
Soil
Well Drained
Water
Moderate
Hardiness
Zone Zones 5a–8b
Bloom Time
February to March
Fall Color
Yellow, orange, red, burgundy
Origin
Northern Iran (Caspian region), southeastern Azerbaijan

Phenological Calendar

As of April 28, 2026, Puget Sound stations range from 1536.6 to 1694.7 GDD₃₂. Persian Ironwood has passed leaf emergence (958 GDD₃₂).

Regional Season Tracker

GDD₃₂ accumulation across 7 Puget Sound stations · as of Apr 28, 2026
Station GDD₃₂ Current Stage Next To Go
Issaquah / East King 1,695 Leaf emergence
Seattle / UW 1,654 Leaf emergence
Kent / Auburn 1,644 Leaf emergence
Olympia / Tumwater 1,603 Leaf emergence
Bellingham / Whatcom 1,591 Leaf emergence
Tacoma / Puyallup 1,572 Leaf emergence
Sequim / Rain Shadow 1,537 Leaf emergence
Stage GDD32 Typical Window
Leaf emergence BBCH 10 NOW 958 Mar 15-Mar 30
Leaf expansion BBCH 12 Mar 25-Apr 10
Leaf senescence / fall color BBCH 93 Oct 15-Nov 15

GDD = Growing Degree Days (base 32°F, Jan 1 start). Why base 32? Hover over GDD values for source details. Season tracker for Kent / Auburn as of Apr 28, 2026. Predicted dates use 16-day weather forecast through May 14, 2026, then climate normals.