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Cork elm

Ulmus thomasii

Last reviewed: September 2026

Cork elm (Ulmus thomasii)

Toxicity unknown

Cork elm (Ulmus thomasii) is not listed by the ASPCA Animal Poison Control Center (opens in new tab) or the other sources we check, so we have no verdict for it either way. Absence from those lists is not a clearance. If your pet shows symptoms after eating any plant, call the ASPCA at (888) 426-4435.

Light

full sun

Water

medium

Size

480"–840" H × 300"–480" W

Bloom

Mar, Apr

Native to

AR, IA, IL, IN and 15 more states

Before you buy

Your city may pay you to plant this

Cities and water utilities offer rebates for replacing lawn with native and water-wise plants. We track 452 programs across 44 states, each with a link to the provider and the date we last checked it.

Find rebates in your area

A tall, upright tree with a narrow, vase-like crown, corky-ridged branches, and doubly-toothed leaves that turn yellow in fall.

Wildlife value

Host plant for question mark, eastern comma.

Foliage is a larval host for question mark and eastern comma butterflies, and the tree's structure provides valuable nesting habitat for birds.

Common questions

How much sun does Cork elm need?
Cork elm grows best in full sun conditions.
When does Cork elm bloom?
Cork elm blooms in March and April.
Where is Cork elm native?
Cork elm (Ulmus thomasii) is native to AR, IA, IL, IN and 15 more states, per the World Checklist of Vascular Plants (Kew).
What butterflies or moths does Cork elm host?
Cork elm is a larval host plant for question mark and eastern comma.

Native range data from the World Checklist of Vascular Plants (Kew). Pollinator and host plant associations compiled from GBIF, iNaturalist, and published ecological literature.

If something looks wrong

Common plant problems, and what to check first

These come up on almost any plant. Each guide lists the likely causes in the order they are worth ruling out, with one thing to check before you act on any of them, and links to the source it came from.

See all plant problem guides

Ready to grow Cork elm? Add it to your garden in Pollinator Patch to track it and get season-by-season care guidance.

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