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Hydrangea arborescens

Smooth Hydrangea · Sevenbark · Tree Hydrangea · Wild Hydrangea

Family HydrangeaceaeGenus Hydrangea

Domed heads of tiny green-white buds held above large heart-shaped toothed leaves
FlowerH. ZellCC BY-SA 3.0

About the plant

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

The plant

Habit
shrub or treePlants of the World Online
Habit
Perennial, ShrubPLANTS Database
Height
3-5 ft0.9-1.5 mExtension Gardener Plant Toolbox
Spread
3-5 ft0.9-1.5 mExtension Gardener Plant Toolbox
Flower
Cream/Tan, Green, Pink, WhiteExtension Gardener Plant Toolbox
Blooms
Spring, SummerExtension Gardener Plant Toolbox
Native range
Native to the lower 48 statesPLANTS Database
Hardiness zones
3-9Extension 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), Neutral (6.0-8.0)Extension Gardener Plant Toolbox
Moisture
Good Drainage, MoistExtension 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.

Worth knowing

  • Called sevenbark because its bark peels in several thin layers of different colors. The Cherokee, and later settlers, used the root to treat kidney and bladder stones. Wikipedia: Hydrangea arborescens

This source reports 5 treatments. All are shown.

Protocol 1

DerivedN. C. Deno, 1996

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.

100% germination in 7–21 days.

Seed Germination Theory and Practice, 1st Supplement — N. C. Deno, 1996 · 1st Supplement, Hydrangea p. 49Public domain
Show the original text
Hydrangea (Saxifragaceae). The seeds of both species were received in March and had 6 m of DS. H. arborescens germ. 70L(100% in 1-3 w), 70 GA-3(100% in 2nd w) 70D(none), 40-70L(100% in 3rd w), 40-70D(12% in 3rd w), and 2% in May in OT
Seed Germination Theory and Practice, 1st Supplement, 1st Supplement, Hydrangea p. 49. 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, 1996

Difficulty Moderate Rated by us, not by the source.

Start around December 15, 2026 for a May 3 last frost.

  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 21 days.

100% germination in 21 days.

Seed Germination Theory and Practice, 1st Supplement — N. C. Deno, 1996 · 1st Supplement, Hydrangea p. 49Public domain
Show the original text
Hydrangea (Saxifragaceae). The seeds of both species were received in March and had 6 m of DS. H. arborescens germ. 70L(100% in 1-3 w), 70 GA-3(100% in 2nd w) 70D(none), 40-70L(100% in 3rd w), 40-70D(12% in 3rd w), and 2% in May in OT
Seed Germination Theory and Practice, 1st Supplement, 1st Supplement, Hydrangea p. 49. 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, 1996

Difficulty Low Rated by us, not by the source.

Start around March 22, 2027 for a May 3 last frost.

  1. Gibberellic acid soak

  2. Sow and cover

    Temperature: 70°F 21°C

No stated waiting before sowing. Then 14 days to germinate.

100% germination in 14 days.

Seed Germination Theory and Practice, 1st Supplement — N. C. Deno, 1996 · 1st Supplement, Hydrangea p. 49Public domain
Show the original text
Hydrangea (Saxifragaceae). The seeds of both species were received in March and had 6 m of DS. H. arborescens germ. 70L(100% in 1-3 w), 70 GA-3(100% in 2nd w) 70D(none), 40-70L(100% in 3rd w), 40-70D(12% in 3rd w), and 2% in May in OT
Seed Germination Theory and Practice, 1st Supplement, 1st Supplement, Hydrangea p. 49. 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, 1996

Difficulty High Rated by us, not by the source.

Start around December 15, 2026 for a May 3 last frost.

  1. Cold moist stratification

    Duration: 90 daysTemperature: 40°F 4°C

  2. Warm moist stratification

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

about 3 months from start to step 2. Germination happens during step 2, in 21 days.

12% germination in 21 days.

Seed Germination Theory and Practice, 1st Supplement — N. C. Deno, 1996 · 1st Supplement, Hydrangea p. 49Public domain
Show the original text
Hydrangea (Saxifragaceae). The seeds of both species were received in March and had 6 m of DS. H. arborescens germ. 70L(100% in 1-3 w), 70 GA-3(100% in 2nd w) 70D(none), 40-70L(100% in 3rd w), 40-70D(12% in 3rd w), and 2% in May in OT
Seed Germination Theory and Practice, 1st Supplement, 1st Supplement, Hydrangea p. 49. 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 5

DerivedN. C. Deno, 1996

Difficulty Very high Rated by us, not by the source.

  1. Sow outdoors and leave it

    Up in May.

No stated waiting before sowing.

2% germination.

This source doesn't state how long step 1 lasts.

Seed Germination Theory and Practice, 1st Supplement — N. C. Deno, 1996 · 1st Supplement, Hydrangea p. 49Public domain
Show the original text
Hydrangea (Saxifragaceae). The seeds of both species were received in March and had 6 m of DS. H. arborescens germ. 70L(100% in 1-3 w), 70 GA-3(100% in 2nd w) 70D(none), 40-70L(100% in 3rd w), 40-70D(12% in 3rd w), and 2% in May in OT
Seed Germination Theory and Practice, 1st Supplement, 1st Supplement, Hydrangea p. 49. 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

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