Deno’s GardenMy Garden

Exochorda racemosa

Common Pearlbrush · Common Pearlbush · Pearlbrush

Family RosaceaeGenus Exochorda

White five-petalled flowers with green centers opening along twigs set with oval leaves
FlowerKENPEICC BY-SA 3.0

About the plant

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

The plant

Habit
shrubPlants of the World Online
Habit
Perennial, ShrubPLANTS Database
Height
10 ft3 mExtension Gardener Plant Toolbox
Spread
10-15 ft3-4.6 mExtension Gardener Plant Toolbox
Flower
WhiteExtension Gardener Plant Toolbox
Blooms
SpringExtension Gardener Plant Toolbox
Native range
China North-Central, China South-Central, China Southeast, Kirgizstan, Korea, Manchuria and elsewhereGBIF Backbone Taxonomy
Hardiness zones
4-8Extension Gardener Plant Toolbox

Growing conditions

Sun
Full sun; Partial ShadeExtension Gardener Plant Toolbox
Soil
High Organic Matter, Loam (Silt)Extension Gardener Plant Toolbox
Soil pH
Acid (<6.0)Extension Gardener Plant Toolbox
Moisture
Good DrainageExtension Gardener Plant Toolbox

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

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

Worth knowing

  • Pearlbush gets its common name from its pearl-like flowers. It comes mainly from China and Japan, and was first described by John Lindley. Wikipedia: Exochorda racemosa

This source reports 4 treatments. All are shown.

Protocol 1

DerivedN. C. Deno, 1993

Difficulty Low Rated by us, not by the source.

Start around January 11, 2027 for a May 3 last frost.

  1. Cold moist stratification

    Temperature: 40°F 4°C Light: either

Germination happens during step 1, in 84 days.

97% germination in 49–84 days.

Seed Germination Theory and Practice, 2nd ed. — N. C. Deno, 1993 · Ch. 20, Exochorda p. 143Public domain
Show the original text
Exochorda (Rosaceae). E. grandiflora germ. best at 40(97% in 7-12 w) and poorer in 70(41% in 1-12 w)-40(36% in 5th w). Light blocks the germination at 70, but has no permanent effect since germination occurs at the same percentage and rate when shifted to 70D. Seeds DS 6 m at 70 germ. faster as shown by 40(92% in 3-6 w) and 70(79% in 1-4 w).
Seed Germination Theory and Practice, 2nd ed., Ch. 20, Exochorda p. 143. 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 Low Rated by us, not by the source.

Start around August 27, 2027 for a May 3 last frost. Too late for spring 2027 — that needed starting on August 26, 2026.

  1. Dry storage

    Duration: 180 daysTemperature: 70°F 21°C

  2. Cold moist stratification

    Temperature: 40°F 4°C Light: either

about 6 months from start to step 2. Germination happens during step 2, in 42 days.

92% germination in 21–42 days.

Seed Germination Theory and Practice, 2nd ed. — N. C. Deno, 1993 · Ch. 20, Exochorda p. 143Public domain
Show the original text
Exochorda (Rosaceae). E. grandiflora germ. best at 40(97% in 7-12 w) and poorer in 70(41% in 1-12 w)-40(36% in 5th w). Light blocks the germination at 70, but has no permanent effect since germination occurs at the same percentage and rate when shifted to 70D. Seeds DS 6 m at 70 germ. faster as shown by 40(92% in 3-6 w) and 70(79% in 1-4 w).
Seed Germination Theory and Practice, 2nd ed., Ch. 20, Exochorda p. 143. 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

Difficulty Low Rated by us, not by the source.

Start around September 10, 2027 for a May 3 last frost. Too late for spring 2027 — that needed starting on September 9, 2026.

  1. Dry storage

    Duration: 180 daysTemperature: 70°F 21°C

  2. Sow and cover

    Temperature: 70°F 21°C Light: either

about 6 months from start to sowing. Then 28 days to germinate.

79% germination in 7–28 days.

Seed Germination Theory and Practice, 2nd ed. — N. C. Deno, 1993 · Ch. 20, Exochorda p. 143Public domain
Show the original text
Exochorda (Rosaceae). E. grandiflora germ. best at 40(97% in 7-12 w) and poorer in 70(41% in 1-12 w)-40(36% in 5th w). Light blocks the germination at 70, but has no permanent effect since germination occurs at the same percentage and rate when shifted to 70D. Seeds DS 6 m at 70 germ. faster as shown by 40(92% in 3-6 w) and 70(79% in 1-4 w).
Seed Germination Theory and Practice, 2nd ed., Ch. 20, Exochorda p. 143. 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 4

DerivedN. C. Deno, 1993

Difficulty Moderate Rated by us, not by the source.

Start around January 11, 2027 for a May 3 last frost.

  1. Warm moist stratification

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

  2. Cold moist stratification

    Duration: 90 daysTemperature: 40°F 4°C Light: either

    36 germinated in this phase.

Steps after step 1 run on after germination.

Germination happens during step 1, in 84 days.

41% germination in 7–84 days.

Seed Germination Theory and Practice, 2nd ed. — N. C. Deno, 1993 · Ch. 20, Exochorda p. 143Public domain
Show the original text
Exochorda (Rosaceae). E. grandiflora germ. best at 40(97% in 7-12 w) and poorer in 70(41% in 1-12 w)-40(36% in 5th w). Light blocks the germination at 70, but has no permanent effect since germination occurs at the same percentage and rate when shifted to 70D. Seeds DS 6 m at 70 germ. faster as shown by 40(92% in 3-6 w) and 70(79% in 1-4 w).
Seed Germination Theory and Practice, 2nd ed., Ch. 20, Exochorda p. 143. 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.

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

Add to My Garden

View species page