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Betulaceae family

Italian Alder Alnus cordata

Also known as: Alder of Corsica

Italian Alder is an introduced perennial tree, found in the lower 48 states. It grows to 62 ft.

More about this plant

Alnus cordata, the Italian alder, is a tree or shrub species belonging to the family Betulaceae, and native to the southern Apennine Mountains and the north-eastern mountains of Corsica. It has been introduced in Sicily, Sardinia, and more recently in Central-Northern Italy, other European countries and extra-European countries, where it has become naturalised. Wikipedia →

Growing & care

USDA PLANTS · TRY
Conditions
Sources · Conditions
Cold hardiness (derived) — Hardiness
Hardiness
≥ zone 11 derived from its U.S. range
Size & form
Sources · Size & form
TRY Plant Trait Database (CC BY 4.0) — Height · Foliage
USDA PLANTS — Lifespan
Height
62 ft
Lifespan
Perennial
Foliage
Deciduous broadleaf
In the garden
Canopy layer — Sits in the canopy of a layered food forest or polyculture.Open guide →
Nitrogen fixer — Fixes atmospheric nitrogen through root-nodule bacteria — builds soil fertility for itself and its neighbours, cutting fertiliser need.Open guide →
Chop-and-drop biomass — Soft, low-density wood is quick-growing and easy to cut back — coppice it and drop the trimmings in place as mulch.Open guide →
derived roles
Species characteristics from USDA PLANTS (public domain) + TRY (CC BY) — general guidance, not a guarantee for your exact site. Deer "browsing" is documented palatability, not a deer-proof claim.

Wildlife & pollinators

How pollinator value is scored →
❧ Caterpillar hosts ~255 caterpillar species · keystone genus

Alnus supports ~255 caterpillar species.

Native butterfly & moth caterpillars are the base of the terrestrial food web — most songbirds rear their young almost entirely on them. As a host for native Lepidoptera this is a powerhouse genus.

Recorded feeding on Alnus in North America, including:

Abagrotis variata · owlet moth Acerra normalis · owlet moth Achatia distincta · Distinct Quaker Achatodes zeae · Elder Shoot Borer Acleris braunana · leafroller moth Acleris caliginosana · leafroller moth
+ 8 more species →
Acleris cervinana · leafroller moth Acleris cornana · leafroller moth Acleris fuscana · Small Aspen Leaftier Acleris hudsoniana · leafroller moth Acleris inana · Inane Acleris Acleris logiana · leafroller moth Acleris maccana · leafroller moth Acleris semiannula · leafroller moth
Keystone count (genus-level) from Warren II 2026 (CC0) · Tallamy host-use records. Named species (a documented Nearctic sample, not exhaustive) from NHM HOSTS (CC0).
✦ Bees 1 bee visitor

1 native & managed bee species is documented visiting Italian Alder :

Bombus terrestris · Buff-Tailed Bumblebee
Visitor records (observations, not exhaustive) from Noori et al. 2026 (CC BY 4.0) · GloBI →
Species thumbnails re-hosted from iNaturalist — Creative Commons, credited per image (hover for credit). Click any species to see it on iNaturalist. Not exhaustive; many taxa have no openly-licensed photo yet.
How we know this (2) Methods & honest limits
Leaf build Direct fact

We read each species’ measured specific leaf area (leaf area per unit dry weight) from the Global Spectrum dataset and band it: thin & fast (high SLA), medium, or thick & tough (low SLA). The global median is about 10 mm²/mg.

Honest limits: A species-mean from pooled measurements — individual plants vary with light and site. A broad strategy signal, not a precise per-plant figure.

Díaz, S. et al. (2022) The global spectrum of plant form and function: enhanced species-level trait dataset. Scientific Data 9:755.
Photosynthesis Direct fact

A recorded categorical fact: each species is tagged C3 (standard), C4 (heat/water-efficient) or CAM (succulent, night-time CO₂ uptake) — or a facultative combination. We only show a trait card for the noteworthy C4/CAM cases; C3 is the unremarkable majority, kept in the data but not surfaced as a card.

Kattge, J. et al. TRY plant trait database — Categorical Traits Dataset (2012).
Derived values are computed from open data by a published method — labelled, cited, and never shown as a direct observation. Full methodology →
Sources for this entry (21) Open & cited
[01] Scientific name & family — USDA PLANTS (DwCA, Zenodo 17903503)
[02] Growth habit & duration — USDA PLANTS (DwCA, Zenodo 17903503)
[03] Native status & distribution — USDA PLANTS (DwCA, Zenodo 17903503)
[04] Common name — USDA PLANTS (via GBIF)
[05] Invasive / introduced status — US-RIIS v2.0 (USGS)
[07] Description — Wikipedia (CC BY-SA)
[08] Ecological value — Warren II 2026 (CC0) · Tallamy host-use counts
[11] Functional traits — TRY Plant Trait Database (CC BY 4.0)
[12] Photosynthetic pathway — TRY Plant Trait Database (CC BY 4.0)
[13] Cold hardiness (derived) — Derived from U.S. range × USDA PHZM zones
[14] Nitrogen fixation — Werner et al. 2014 (Dryad, CC0)
[16] Other common names — Wikidata (CC0)
[18] Flower-visitor value (derived) — Noori et al. 2026 (CC BY 4.0) · GloBI
[19] Caterpillar host count — Warren II 2026 (Dryad, CC0) · Tallamy host-use counts
[20] Caterpillar species — NHM HOSTS (CC0)
[21] County range — GBIF Open Data — open-licensed occurrences (CC0/CC-BY) → county
Spot an error or have a better photo? Every field links to its source, and the whole dataset is open.
Cite this page Open data, please attribute

PlantKey’s data is open under CC BY-SA 4.0 — free to reuse and adapt, with attribution and the same licence. Photos keep their own per-image licence + credit (see Sources above).

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