Buttonbush

Cephalanthus occidentalis L.

Family: Rubiaceae

Pet & Human Safety

People: Toxic to people (low severity)Pets: Not on the ASPCA lists as we read them

Hazardous parts

bark

Preparation

n/a

Hazard type

ingestion

Hazard route

ingestion

How complete this information is

We have not researched the safety of this plant yet.

Toxic to pets

No ASPCA entry found.

NC State tags this plant 'problem for horses' and says the bark holds a toxin (cephalathin) that can cause vomiting, convulsions and paralysis if eaten; it does not tag dogs or cats, which is silence, not an all-clear.

PlotAndPetal cannot tell you whether a plant you found can be eaten. Only someone who can see the plant can identify it.

Poison control

If someone has collapsed, cannot be woken, is having a seizure or has trouble breathing, call 911 now. For any other possible poisoning, call Poison Help: 1-800-222-1222.

Emergency number source: U.S. federal law (47 U.S.C. § 251(e)(3)), read 2026-10-07.

Naturalist Lore

Historical Background & Breeding Lore

The history of this plant and its name, and how it was bred, where we have them.

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Care

Hardiness zones: USDA 4A-11B per UF/IFAS EDIS FP117; USDA 5a-9b per NC State Plant Toolbox
Light: Full sun to partial sun (UF/IFAS); full to partial sun (NC State).
Water needs: high
Mature size: US-FL: UF/IFAS: height 6-12 ft, spread 6-10 ft; most specimens are 4-6 ft tall, old plants to 10 ft and more than 12 ft wide on moist sites; US: NC State: 5-8 ft tall, 3-6 ft wide; can grow as a tree up to 20 ft, usually a small shrub up to 12 ft tall and 8 ft wide
Where it comes from: Eastern and southern North America to Central America and Cuba (NC State); UF/IFAS: native to Florida. NC State distribution lists most eastern US states plus New Brunswick, Nova Scotia, Ontario, Prince Edward Island and Quebec.

Soil & Drainage

Pruning & Flush Rhythm

Feeding Schedule

How to prepare the soil, when and what to feed, and how and when to prune where that applies.

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