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Silene chalcedonica

London Pride · Maltese Cross · Maltese-cross Campion

Family CaryophyllaceaeGenus Silene

Flat-topped heads of vivid orange-red flowers, each petal deeply notched, on tall hairy stems with paired leaves.
FlowerUser:Qwertzy2CC BY-SA 3.0

About the plant

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

The plant

Habit
Herbaceous Perennial, PerennialExtension Gardener Plant Toolbox
Habit
perennialPlants of the World Online
Height
1.7-3.3 ft0.5-1 mExtension Gardener Plant Toolbox
Spread
0.3-1.7 ft10-50 cmExtension Gardener Plant Toolbox
Flower
Red/BurgundyExtension Gardener Plant Toolbox
Blooms
Spring, SummerExtension Gardener Plant Toolbox
Native range
Altay, Central European Russia, China North-Central, East European Russia, Irkutsk, Kazakhstan and elsewhereGBIF Backbone Taxonomy
Hardiness zones
3-9Extension Gardener Plant Toolbox

Growing conditions

Sun
Full sun; Partial ShadeExtension Gardener Plant Toolbox
Soil
Loam (Silt), SandExtension Gardener Plant Toolbox
Soil pH
Acid (<6.0), Alkaline (>8.0), 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

  • Maltese cross has many names, among them Jerusalem cross, nonesuch and flower of Bristol, and in 2002 it was voted Bristol's county flower in a poll by the charity Plantlife. It holds the RHS Award of Garden Merit. Wikipedia: Silene chalcedonica

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 March 28, 2027 for a May 3 last frost.

  1. Sow and cover

    Temperature: 70°F 21°C

No stated waiting before sowing. Then 8 days to germinate.

100% germination in 3–8 days.

Seed Germination Theory and Practice, 2nd ed. — N. C. Deno, 1993 · Ch. 20, Lychnis p. 174Public domain
Show the original text
Lychnis (Caryophyllaceae). L. chalcedonica germ. 70(100% in 3-8 d) and 40(10%)-70(90%) for fresh seed and 70(70%) and 40(25%)-70(75%) for seed DS 6 m at 70 or 40.
Seed Germination Theory and Practice, 2nd ed., Ch. 20, Lychnis p. 174. 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 December 15, 2026 for a May 3 last frost.

  1. Cold moist stratification

    Duration: 90 daysTemperature: 40°F 4°C

    10 germinated in this phase.

  2. Warm moist stratification

    Duration: 90 daysTemperature: 70°F 21°C

about 3 months from start to step 2. Germination happens during step 2; time not stated, 21 days assumed.

90% germination.

Seed Germination Theory and Practice, 2nd ed. — N. C. Deno, 1993 · Ch. 20, Lychnis p. 174Public domain
Show the original text
Lychnis (Caryophyllaceae). L. chalcedonica germ. 70(100% in 3-8 d) and 40(10%)-70(90%) for fresh seed and 70(70%) and 40(25%)-70(75%) for seed DS 6 m at 70 or 40.
Seed Germination Theory and Practice, 2nd ed., Ch. 20, Lychnis p. 174. 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 Moderate Rated by us, not by the source.

Start around June 19, 2027 for a May 3 last frost. Too late for spring 2027 — that needed starting on June 18, 2026.

  1. Dry storage

    Duration: 180 days

  2. Cold moist stratification

    Duration: 90 daysTemperature: 40°F 4°C

    25 germinated in this phase.

  3. Warm moist stratification

    Duration: 90 daysTemperature: 70°F 21°C

about 9 months from start to step 3. Germination happens during step 3; time not stated, 21 days assumed.

75% germination.

Seed Germination Theory and Practice, 2nd ed. — N. C. Deno, 1993 · Ch. 20, Lychnis p. 174Public domain
Show the original text
Lychnis (Caryophyllaceae). L. chalcedonica germ. 70(100% in 3-8 d) and 40(10%)-70(90%) for fresh seed and 70(70%) and 40(25%)-70(75%) for seed DS 6 m at 70 or 40.
Seed Germination Theory and Practice, 2nd ed., Ch. 20, Lychnis p. 174. 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 Low Rated by us, not by the source.

Start around September 17, 2027 for a May 3 last frost. Too late for spring 2027 — that needed starting on September 16, 2026.

  1. Dry storage

    Duration: 180 days

  2. Sow and cover

    Temperature: 70°F 21°C

about 6 months from start to sowing. Germination time not stated; 21 days assumed.

70% germination.

Seed Germination Theory and Practice, 2nd ed. — N. C. Deno, 1993 · Ch. 20, Lychnis p. 174Public domain
Show the original text
Lychnis (Caryophyllaceae). L. chalcedonica germ. 70(100% in 3-8 d) and 40(10%)-70(90%) for fresh seed and 70(70%) and 40(25%)-70(75%) for seed DS 6 m at 70 or 40.
Seed Germination Theory and Practice, 2nd ed., Ch. 20, Lychnis p. 174. 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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