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Campanula medium

Canterbury Bellflower · Canterbury Bells · Canterbury-bell

Family CampanulaceaeGenus Campanula

Two inflated violet bell flowers with spreading frilled mouths, above hairy green calyx leaves
FlowerHectonichusCC BY-SA 3.0

About the plant

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

The plant

Habit
Herbaceous PerennialExtension Gardener Plant Toolbox
Habit
biennialPlants of the World Online
Height
1-3 ft30-90 cmExtension Gardener Plant Toolbox
Spread
1-2 ft30-60 cmExtension Gardener Plant Toolbox
Flower
Blue, Pink, Purple/Lavender, WhiteExtension Gardener Plant Toolbox
Blooms
SummerExtension Gardener Plant Toolbox
Native range
France, ItalyGBIF Backbone Taxonomy
Hardiness zones
3-9Extension Gardener Plant Toolbox

Growing conditions

Sun
Dappled Sunlight; Full sun; Partial ShadeExtension Gardener Plant Toolbox
Soil
High Organic Matter, Loam (Silt), SandExtension 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: Extension Gardener Plant Toolbox — NC State Extension; Plants of the World Online — Royal Botanic Gardens, Kew; GBIF Backbone Taxonomy — Global Biodiversity Information Facility.

Worth knowing

  • Canterbury bells, said to be named for the bells of Canterbury Cathedral and those worn by pilgrims. It is the national flower of Monaco. Wikipedia: Campanula medium

This source reports two treatments. Both are shown.

Protocol 1

DerivedN. C. Deno, 1993

Difficulty Moderate Rated by us, not by the source.

Start around December 30, 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 6 days.

90% germination in 6 days.

Seed Germination Theory and Practice, 2nd ed. — N. C. Deno, 1993 · Ch. 20, Campanula p. 110Public domain
Show the original text
Campanula (Campanulaceae). Most species are D-70 germinators. There are some that are 40-70 germinators and photorequirers and C. medium germ. immediately at 70. C. -ossetica has an absolute photorequirement for germination. The seeds germ. 70L(50% in 1-3 w), 70D(none), 40-70L(90% on 6th d), and 40-70D(nohe).
Seed Germination Theory and Practice, 2nd ed., Ch. 20, Campanula p. 110. 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 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.

50% germination in 7–21 days.

Seed Germination Theory and Practice, 2nd ed. — N. C. Deno, 1993 · Ch. 20, Campanula p. 110Public domain
Show the original text
Campanula (Campanulaceae). Most species are D-70 germinators. There are some that are 40-70 germinators and photorequirers and C. medium germ. immediately at 70. C. -ossetica has an absolute photorequirement for germination. The seeds germ. 70L(50% in 1-3 w), 70D(none), 40-70L(90% on 6th d), and 40-70D(nohe).
Seed Germination Theory and Practice, 2nd ed., Ch. 20, Campanula p. 110. 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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