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Cephalanthus occidentalis

Button-willow · Buttonbush · Common Buttonbush

Family RubiaceaeGenus Cephalanthus

A creamy globe of florets bristling with long styles, beside two green buds still packed tight, among glossy leaves.
FlowerRufino Osorio (also known as Desmodium)CC BY-SA 2.5

About the plant

What it is and where it grows — not part of any germination protocol.

The plant

Habit
ShrubExtension Gardener Plant Toolbox
Habit
shrubPlants of the World Online
Height
5-8 ft1.5-2.4 mExtension Gardener Plant Toolbox
Spread
3-6 ft0.9-1.8 mExtension Gardener Plant Toolbox
Flower
Cream/Tan, WhiteExtension Gardener Plant Toolbox
Blooms
SummerPLANTS Database
Native range
Alabama, Arizona, Arkansas, Belize, California, Connecticut and elsewhereGBIF Backbone Taxonomy
Hardiness zones
5-9Extension Gardener Plant Toolbox

Growing conditions

Sun
Full sun; Partial ShadeExtension Gardener Plant Toolbox
Soil
Clay, High Organic Matter, Loam (Silt), Sand, Shallow RockyExtension Gardener Plant Toolbox
Soil pH
Acid (<6.0)Extension Gardener Plant Toolbox
Moisture
Frequent Standing Water, Moist, Occasionally Dry, Occasionally WetExtension Gardener Plant Toolbox
Watering
Drought tolerance: MediumPLANTS Database

Toxicity is noted only where a source states it. No note here is not a finding of safety.

Sources: Extension Gardener Plant Toolbox — NC State Extension; Plants of the World Online — Royal Botanic Gardens, Kew; PLANTS Database — USDA NRCS; GBIF Backbone Taxonomy — Global Biodiversity Information Facility.

Worth knowing

This source reports three treatments. All are shown.

Protocol 1

DerivedN. C. Deno, 1993

Difficulty Low Rated by us, not by the source.

Start around March 15, 2027 for a May 3 last frost.

  1. Sow and cover

    Temperature: 70°F 21°C Light: light

No stated waiting before sowing. Then 21 days to germinate.

80% germination in 21 days.

Seed Germination Theory and Practice, 2nd ed. — N. C. Deno, 1993 · Ch. 20, Cephalanthus p. 116Public domain
Show the original text
Cephalanthus (Rubiaceae). C. occidentalis has an absolute light requirement for germination, and none germ. in the dark as shown by 70L(80-90% in 1 3 w), 40-70L(80-90% in 13 w), and none in 70D or 40-70D. Results were the same for fresh seed or seed DS 6 m at 70 or 40.
Seed Germination Theory and Practice, 2nd ed., Ch. 20, Cephalanthus p. 116. Quoted exactly. Every value on this card comes from this record, except the difficulty rating, which is ours; the step names come from a fixed list.

Protocol 2

DerivedN. C. Deno, 1993

Difficulty Moderate Rated by us, not by the source.

Start around October 7, 2027 for a May 3 last frost. Too late for spring 2027 — that needed starting on October 6, 2026.

  1. Cold moist stratification

    Duration: 90 daysTemperature: 40°F 4°C

  2. Warm moist stratification

    Duration: 90 daysTemperature: 70°F 21°C Light: light

about 3 months from start to step 2. Germination happens during step 2, in 91 days.

80% germination in 91 days.

Seed Germination Theory and Practice, 2nd ed. — N. C. Deno, 1993 · Ch. 20, Cephalanthus p. 116Public domain
Show the original text
Cephalanthus (Rubiaceae). C. occidentalis has an absolute light requirement for germination, and none germ. in the dark as shown by 70L(80-90% in 1 3 w), 40-70L(80-90% in 13 w), and none in 70D or 40-70D. Results were the same for fresh seed or seed DS 6 m at 70 or 40.
Seed Germination Theory and Practice, 2nd ed., Ch. 20, Cephalanthus p. 116. Quoted exactly. Every value on this card comes from this record, except the difficulty rating, which is ours; the step names come from a fixed list.

Protocol 3

DerivedN. C. Deno, 1993

  1. Sow and cover

    Temperature: 70°F 21°C Light: dark

No stated waiting before sowing.

0% germination.

Nothing germinated at 70.

Seed Germination Theory and Practice, 2nd ed. — N. C. Deno, 1993 · Ch. 20, Cephalanthus p. 116Public domain
Show the original text
Cephalanthus (Rubiaceae). C. occidentalis has an absolute light requirement for germination, and none germ. in the dark as shown by 70L(80-90% in 1 3 w), 40-70L(80-90% in 13 w), and none in 70D or 40-70D. Results were the same for fresh seed or seed DS 6 m at 70 or 40.
Seed Germination Theory and Practice, 2nd ed., Ch. 20, Cephalanthus p. 116. Quoted exactly. Every value on this card comes from this record; the step names come from a fixed list.

How each step is done, in Deno’s words, and what Verified and Derived mean.

Germination trials

Readers’ own records of sowing this species, published after review. Share your trial · All trials

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