Deno’s Garden

Helianthemum oelandicum

Hoary Rock Rose

Family CistaceaeGenus Helianthemum

Two yellow flowers with orange stamens, opening over gravel
FlowerVictor M. Vicente SelvasPublic domain

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.