Height at maturity: 80 cm
Spread at maturity: 15-45 cm
Light needs: Part sun to full sun
Hardiness: USDA Zones 2-11
Type of soil: Rich, fertile, well-draining
Soil pH: Sandy or chalky soils
Where to plant: Borders, beds, containers, windowboxes
Features: Cut flowers, attracts pollinators, good dried/pressed flower
Pruning: Deadhead by cutting spent flower spikes back to small flowering side shoots. This will encourage further blooms. Cut down all growth to ground level once it has withered in autumn.
Flowering period: Spring to summer (as soon as three months after planting)
Best time to sow seeds: Spring or fall
Common names: Line flower, Knight's-Spur
Plant type: Annual
Difficulty: Easy; low maintenance
Larkspur (Delphinium consolidata) are an easy-to-grow and unfussy plant, but there is still one important factor to take into consideration: these seeds must have a cold period in order to germinate. In most places, this means that you should sow the seeds directly in the ground in the fall.
If it does regularly stay colder than 18 C (64 F) during the winter, they will not grow.
In warmer climates, the best way to ensure a cold spell is to pop them in the fridge in an airtight plastic bag for two weeks before planting. Once planted, the seeds should germinate within three weeks.
Start with well-draining soil. If planting in pots, make sure there are adequate drainage holes at the bottom. You can sow them directly in the ground since the roots do not like being transplanted.
Space the seeds around 15-20 cm (6-8 inches) apart then top with a very light layer of soil. They really should never be more than half a centimeter deep.
Water deeply to encourage root development, but be sure the roots do not stand in water as they will rot.
Sow your larkspur seeds indoors in spring, or under glass in autumn/winter. Indoors, surface sow onto moist, well-drained seed compost. Just cover seed with a sprinkling of vermiculite. Germination may occur in 2-4 weeks.
Seed can be sown autumn-winter, surface sow, just cover with vermiculite, place somewhere dry and frost free, a garage or greenhouse is ideal.
