Mendel’s Gardens

Helianthemum oelandicum

Hoary Rock Rose

Family CistaceaeGenus Helianthemum

This source reports two treatments. Both are shown.

Protocol 1

DerivedN. C. Deno, 1993

Difficulty High Rated by us, not by the source.

Start around March 12, 2027 for a May 3 last frost.

  1. Warm moist stratification

    Temperature: 70°F 21°C

    Four seeds of seventeen, in 3-24 days.

  2. Cold moist stratification

    Temperature: 40°F 4°C

    One more of seventeen.

  3. Warm moist stratification

    Temperature: 70°F 21°C

No stated waiting before sowing. Then 24 days to germinate.

24% germination in 3–24 days.

This source doesn't state how long.

Seed Germination Theory and Practice, 2nd ed. — N. C. Deno, 1993 · Ch. 20, HelianthemumPublic domain
Show the original text
Helianthemum (Cistaceae). H. oelandicum germ. 70(4/17 in 3-24 d)-40(1/17)-70 and 40-70(1123)-40(2/23).
Seed Germination Theory and Practice, 2nd ed., Ch. 20, Helianthemum. 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

  1. Cold moist stratification

    Temperature: 40°F 4°C

  2. Warm moist stratification

    Temperature: 70°F 21°C

    The figure here is damaged in the scan.

  3. Cold moist stratification

    Temperature: 40°F 4°C

    Two seeds of twenty-three in the second cold period.

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

The first figure of this run is unreadable; the quotation has it as printed.

This source doesn't state how long.

Seed Germination Theory and Practice, 2nd ed. — N. C. Deno, 1993 · Ch. 20, HelianthemumPublic domain
Show the original text
Helianthemum (Cistaceae). H. oelandicum germ. 70(4/17 in 3-24 d)-40(1/17)-70 and 40-70(1123)-40(2/23).
Seed Germination Theory and Practice, 2nd ed., Ch. 20, Helianthemum. Quoted exactly. Every value on this card comes from this record; the step names come from a fixed list.