GENERAL INFORMATION
Scientific Name: Helianthemum nummularium
CommonName: Rock Rose
Hardiness Zone: 5a - 8b
Hardiness Degree: -20°F (-29°C)
Blooming Season: Spring, Late Spring
Plant Habit: Mounded, Spreading
Characteristics: Attracts Bees, Attracts Butterflies, Deer Resistant, Low Maintenance, Frost Tolerant
Water: Light
Fertilizer: None or when needed only
Spacing: 18 - 22" (46 - 56cm)
Height: 8 - 12" (20 - 30cm)
Width: 16 - 20" (41 - 51cm)
Exposure: Sun
PROPAGATION
Media EC/pH: EC 0.75-0.80 mmhos/pH 5.8-6.2
Soil Temperature: 70-72°F (21-22°C)
Rooting Hormone: 500 ppm IBA
Mist: Low; prefers high humidity rather than mist.
Fertilization: 50-75 ppm N
Pinching: Recommended after roots are established. Leave 4-5 active internodes.
Transplanting: 42-56 days after sticking
FINISHING
Media pH: 5.8-6.2
Temperature: Nights: 56 to 64°F (13 to 18°C) Days: 65 to 76°F (18 to 24°C)
Light Level (fc): 5,000 to 8,000
Vernalization: Yes
Daylength: Day length neutral
Watering: Allow media to dry slightly between watering.
Fertilization: Use a balanced fertilizer at a rate of 100 to 125 ppm.
Pinch After Transplant: Recommended
Plant Growth Regulators: PGRs generally not needed
Pests and Fungal Diseases: Botrytis can result from overwatering. Thrips, white fly, aphids, fungus gnats.
CROP SCHEDULING
1–qt. (10–cm) pot, 1 plant per pot: 7-10 wks
1–gal. (15–cm) pot, 1 plant per pot: 9-11 wks, 1-3 ppp
2 to 3–gal. (25 to 30–cm) pot, 3 plants per pot: 10-12 wks, 3-5 ppp
Bloom Months: April to June