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Rhododendron catawbiense

Catawba Rosebay · Catawba Rhododendron · Purple Ivy

Family EricaceaeGenus Rhododendron

A rounded shrub of long dark leaves carrying trusses of pale pink flowers with freckled throats, at the edge of a bark path.
The whole plantNo machine-readable author provided. Edgester assumed (based on copyright claims).CC BY-SA 3.0

About the plant

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

The plant

Habit
Perennial, ShrubExtension Gardener Plant Toolbox
Habit
shrub or treePlants of the World Online
Height
6-10 ft1.8-3 mExtension Gardener Plant Toolbox
Spread
8-10 ft2.4-3 mExtension Gardener Plant Toolbox
Flower
Gold/Yellow, Green, Pink, Purple/LavenderExtension Gardener Plant Toolbox
Blooms
Spring, SummerExtension Gardener Plant Toolbox
Native range
Native to the lower 48 statesPLANTS Database
Hardiness zones
4-8Extension Gardener Plant Toolbox

Growing conditions

Sun
Deep shade; Full sun; Partial ShadeExtension Gardener Plant Toolbox
Soil
High Organic MatterExtension Gardener Plant Toolbox
Soil pH
Acid (<6.0)Extension Gardener Plant Toolbox
Moisture
Good Drainage, Moist, Occasionally DryExtension Gardener Plant Toolbox

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.

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 7–21 days.

Seed Germination Theory and Practice, 2nd ed. — N. C. Deno, 1993 · Ch. 20, Rhododendron p. 204Public domain
Show the original text
Rhododendron (Ericaceae). Usually light was required for germination. A. catawbiense hybrids germ. 70L(80-85% in 1-3 w) and less in 70D(5-25%) or 40-70D(15%). A prior 3 m at 40 had little effect. Outdoor treatment ultimately germ. 73%, but germination extended from May to August and is inconvenient. Fresh seed and seed DS 6 m at 70 or 40 gave identical results in all treatments.
Seed Germination Theory and Practice, 2nd ed., Ch. 20, Rhododendron p. 204. 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 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; time not stated, 21 days assumed.

15% germination.

Seed Germination Theory and Practice, 2nd ed. — N. C. Deno, 1993 · Ch. 20, Rhododendron p. 204Public domain
Show the original text
Rhododendron (Ericaceae). Usually light was required for germination. A. catawbiense hybrids germ. 70L(80-85% in 1-3 w) and less in 70D(5-25%) or 40-70D(15%). A prior 3 m at 40 had little effect. Outdoor treatment ultimately germ. 73%, but germination extended from May to August and is inconvenient. Fresh seed and seed DS 6 m at 70 or 40 gave identical results in all treatments.
Seed Germination Theory and Practice, 2nd ed., Ch. 20, Rhododendron p. 204. 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 Very high 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: dark

No stated waiting before sowing. Germination time not stated; 21 days assumed.

5% germination.

Seed Germination Theory and Practice, 2nd ed. — N. C. Deno, 1993 · Ch. 20, Rhododendron p. 204Public domain
Show the original text
Rhododendron (Ericaceae). Usually light was required for germination. A. catawbiense hybrids germ. 70L(80-85% in 1-3 w) and less in 70D(5-25%) or 40-70D(15%). A prior 3 m at 40 had little effect. Outdoor treatment ultimately germ. 73%, but germination extended from May to August and is inconvenient. Fresh seed and seed DS 6 m at 70 or 40 gave identical results in all treatments.
Seed Germination Theory and Practice, 2nd ed., Ch. 20, Rhododendron p. 204. 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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