Buttonbush (Cephalanthus occidentalis) - white flowers, illustrated plant cardIllustration

Buttonbush

Cephalanthus occidentalis

Also called common buttonbush, button bush, button willow, honeybells and honey balls

Buttonbush blooms from June through August.

Bloom calendar
Bloom time
Jun–Aug
checked
Hardiness
Zones 5–9
checked
Sun
Full sun
checked
Water
Moderate water
checked
Mature size
8.5 ft × 6 ft
checked
Type
Shrub
house classification

Months here are Northern Hemisphere months; in the Southern Hemisphere, shift them by six months.

Growing Buttonbush

Plant it in full sun. It prefers moderate water. It is hardy in USDA zones 5–9. Expect it to reach about 8.5 ft tall and 6 ft wide at maturity, in roughly 4 years (a house reading).

No toxicity note is on file for Buttonbush. That is not a clearance: check its safety for people and pets before planting.

Verification
What was checked

Mature height and spread, hardiness zones, sun, water, bloom months and color and the trait tags were checked against named botanical sources for this plant, with what the sources could not settle written down; years to mature size rests on a recorded house rule where no publisher states one, and is marked so; its common name and alternate names have not been checked yet. Each fact above carries its own mark. The planting, spacing and size sections are derived from these checked facts by a fixed rule, not checked separately, and the plant type is the library's own classification.

See the 7 sources it was checked against

When to plant Buttonbush

Plant Buttonbush in early spring as soon as the soil is workable, or in early fall at least six weeks before your first frost, so roots establish in cool weather. In zone 7, the middle of its hardy zones 5 to 9, spring means March to May and fall means September or October. Once settled, it blooms from June to August.

Month-by-month timing for your zone is on the planting calendar; if you garden near zone 7, the middle of this plant's hardy range, start with zone 7 in March. Derived from the plant's category, zones and bloom months plus typical zone frost dates, not checked separately.

How big does Buttonbush get?

Illustration of Buttonbush drawn to scale beside an adult8.5 fttall5 ft 7 inan adult6 ftwide
About 8.5 ft tall and 6 ft wide at maturity: half again as tall as an adult.

See Buttonbush in a garden plan: the planner shows it in 3D beside everything else you add, growing toward this size over the years.

How far apart to plant Buttonbush

Derived from the mature spread above by a fixed rule, not checked separately: spacing is the spread, center to center.

Space Buttonbush about 6 ft apart, center to center, so each plant has room to reach its full width.

Plant them
6 ft apart
Per 10 sq ft
one needs about 36 sq ft
4 by 8 ft bed
about 1

Add Buttonbush to a garden plan and the planner draws it at its full width, so you see the spacing before you buy.

Where these facts come from

Buttonbush's height, spread, hardiness zones, sun, water, bloom months and color, trait tags, soil, diseases, pests and toxicity were checked against 7 published sources on September 23, 2026. Each one is linked below with every fact it carried, which can include a fact this page still marks as not yet checked, because a source carrying a value is not the same as the value being held to the standard. Facts not in that list, and the planting, spacing and size sections, are not covered by these sources.

  • NC State ExtensionGardener Plant Toolboxheight, spread, hardiness zones, sun, water, bloom months and color, trait tags, soil, diseases, pests and toxicity
  • Missouri Botanical GardenPlant Finderheight, spread, hardiness zones, sun, water, bloom months and color, trait tags, soil, diseases and pests
  • Plant Addictsheight, spread, hardiness zones, sun, water, bloom months and color, soil and pests
  • plantdatabase.uconn.eduUniversity of Connecticut Plant Databaseheight, spread, hardiness zones, sun, water, bloom months and color, diseases and pests
  • Lady Bird Johnson Wildflower CenterUniversity of Texas at Austinheight, sun, water, bloom months and color, soil, pests and toxicity
  • Prairie Moon Nurseryheight, spread, hardiness zones, sun, water, bloom months and color and toxicity
  • The Morton Arboretumheight, spread, hardiness zones, sun, water, bloom months and color and soil

How the checking works, and what each standard covers, is on the verified plants page.

1 more variety in the Buttonbush group

Same plant, same care - pick the variety you are growing.

Compare every variety in the Buttonbush group

Every figure is the variety's own page fact. Tap a name to open it.

VarietyColorBloomsHardinessSunSize (H × W)
Buttonbushthis pageWhiteJun–AugZones 5–9Full sun8.5 ft × 6 ft
Sugar ShackWhiteJun–AugZones 4–10Full sun4 ft × 4 ft

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