Alnus cordata
Italian alder
(c) Jacqui Geux, some rights reserved (CC BY), uploaded by Jacqui Geux · licence
Family: Betulaceae · Type: Tree · Not Native
Alnus cordata (Italian alder) is a non-native California tree in the Betulaceae family, recognized by distinguishable by non-native status, low elevation habitat, and cordate leaf base.
Italian alder is a naturalized tree found in northern coastal California, specifically in the Santa Rosa area of Spring Lake Park, at elevations below 310 meters. Flowering from October to November, this tree produces flowers typical of alders, though specific color details are not provided. Growing to heights exceeding 9 meters with substantial trunks, it has an upright, robust tree form. Its leaves are distinctive, with heart-shaped (cordate) to flat (truncate) bases, obtuse to short-pointed tips, and margins that are slightly flat with rounded teeth, generally smooth with occasional hair tufts in leaf vein intersections. This tree, originally from Italy, has established itself as a garden escape in California's landscape.
Identification and appearance
Key characters: 3 sympatric species; distinguishable by non-native status, low elevation habitat, and cordate leaf base
Habitat and range
Habitat: Garden escape
Elevation: < 310 m
Outside California: native to Italy, Corsica
Bloom period
Alnus cordata blooms Oct-Nov(in Italy).
How to tell it apart
vs Corylus: Alnus has tiny winged seeds from persistent woody cones; Corylus has large nuts in papery husks.; vs Populus: Alnus has woody persistent cone-like catkins; Populus has fluffy cottony seeds from capsules.; vs Quercus: Alnus has woody cone-like catkins and toothed leaves; Quercus has acorns in caps and lobed leaves.; vs Betula: Alnus has woody cones that persist after seeds drop; Betula catkins disintegrate completely, releasing papery scales with seeds.; vs Ulmus: Alnus has woody cone-like catkins; Ulmus has flat, round, papery winged fruits.
Frequently asked questions
Is Alnus cordata native to California?
No. Alnus cordata is not native to California (recorded as not native).
When does Alnus cordata bloom?
Alnus cordata blooms Oct-Nov(in Italy).
What plant family does Alnus cordata belong to?
Alnus cordata is in the Betulaceae family, genus Alnus.
What habitat does Alnus cordata grow in?
Alnus cordata grows in Garden escape.
Related species
Other California species in the same genus, family, or bioregion.
Sources: Jepson eFlora · CalPhotos
Last updated 2026-10-07
Data from The California Species Project — 14,000+ California species with verified data from CNPS, CDFW, USFWS, Cal-IPC, and more.