Larkspur is a popular flower grown for its tall spires of colorful flowers that bloom from late spring through mid summer. Knowing when to plant larkspur is key to getting the most out of these classic cottage garden plants. Larkspur can be planted in spring or fall, depending on your climate and gardening goals.
When to Plant Larkspur
Spring Planting
Spring is the most common time to plant larkspur. This allows the seeds to germinate and become established before hot summer weather arrives. Here are spring planting guidelines for larkspur:
– In most climates, plant larkspur seeds outdoors 4-6 weeks before the last expected spring frost date. This gives larkspur time to sprout and grow a bit before cold weather has passed.
– Start seeds indoors 2-4 weeks before your outdoor planting date. Then harden off and transplant seedlings into the garden. This gives larkspur a head start on the season.
– In warm winter climates (zones 8-10), larkspur can be planted in late winter. Wait until daytime temps are consistently in the 60s F.
– Sow seeds 1/4-1/2 inch deep. Full sun is best but larkspur will tolerate partial shade. Keep soil moist until seeds germinate.
Fall Planting
Larkspur seeds can also be planted in fall in zones 7-10. Here are fall planting tips:
– Sow seeds 6-8 weeks before the first expected fall frost. This gives larkspur time to sprout before winter dormancy.
– Start seeds indoors 2-3 weeks before your outdoor planting date to give them a boost. Harden off before transplanting.
– Choose a spot with full sun to partial shade. Prepare soil by mixing in compost or aged manure.
– Sow seeds 1/4-1/2 inch deep. Water gently and keep soil moist while seeds germinate.
– Mulch newly sprouted larkspur to protect it from frigid winter temps. Remove mulch in spring as growth resumes.
– Expect larkspur planted in fall to bloom the following early summer.
What Type of Larkspur to Plant
Annual Larkspur
Annual larkspur (Consolida spp.) is the most popular type grown from seed each year. It grows 3-4 feet tall on upright stems lined with feathery, lobed leaves. Flower spikes appear in summer, blooming in shades of pink, purple, blue, white and bicolors. Popular annual varieties include:
– Giant Imperial – Giant flower spikes to 4 feet tall in mix of colors.
– Rocket – Early blooming mix ideal for spring planting.
– Blue Cloud – Pure blue flowers on compact 30 inch plants.
-White Cloud – Pure white version of Blue Cloud.
– Carmine King – Brilliant carmine-red blossoms.
– Pink Punch – Bright pink flowers with white centers
Perennial Larkspur
Perennial larkspur (Delphinium spp.) is a classic cottage garden favorite that can live for many years. It grows taller than annuals, from 4-6 feet high. Colors include deep blues, vibrant purples, pinks, reds, yellows and white. Popular perennial types include:
– Magic Fountains – Dwarf variety to 3 feet, mix of colors.
– Guardian – Dark blue heavy bloomer reaching 5 feet.
– Blue Donna – Reliable 4 foot blue-flowered variety.
– Ruby Red – Deep rosy-red blossoms.
– Yellow Hammer – Bright lemon-yellow flowers.
– Black Knight – Deep purple flowers with black centers.
– Gold Medal Hybrids – Giant flower spikes in mix of colors.
When to Plant Perennial vs. Annual Larkspur
Annual larkspur is planted new each year and ideal for spring planting. Perennial larkspur can be planted in spring or fall. In spring, start perennial larkspur seeds 6-8 weeks before annuals for blooms the first season. In fall, plant perennial larkspur at the same time as annuals. Mulch the perennial crop to survive winter.
Where to Plant Larkspur
Sun Exposure
When choosing a spot for larkspur, go for full sun to light shade. Most types thrive in a minimum of 6 hours of direct sun daily. Morning sun is ideal as it allows plants to dry out after morning dew or rain. Afternoon shade prevents overheating.
Soil Needs
Larkspur prefers nutrient-rich, well-drained soil. Amend garden beds with 2-3 inches of compost or aged manure before planting. This provides nutrients for growth and improves moisture retention in the soil. Maintain soil pH between 6-7.
Spacing
Allow 8-12 inches between annual larkspur plants and 12-18 inches for perennial types. Wider spacing reduces fungal disease issues. Plant in groups of 3-5 plants for visual impact.
How to Plant Larkspur
From Seeds
The most common method is planting larkspur from seeds sown directly in the garden. Follow these tips:
– Prepare soil by mixing in compost. Break up any clumps and rake smooth.
– Sow seeds 1/4-1/2 inch deep. Space seeds or thin seedlings to proper spacing.
– Water gently after sowing. Keep soil moist until seeds germinate in 10-20 days.
– Thin annuals to 8-12 inches apart. Thin perennials to 12-18 inches apart.
Start Indoors
For a head start, sow larkspur seeds indoors 4-6 weeks before outdoor planting time. Here?s how:
– Fill pots or trays with seed starting mix. Moisten soil before planting.
– Sow seeds 1/4 inch deep. Cover trays to retain moisture.
– Place pots in bright light at 65-70°F until sprouted.
– Transplant outdoors after hardening off for 7-10 days.
Transplants
You can also buy pre-started larkspur plants or transplants from nurseries. Look for stocky, green plants without flowers. Transplant into garden beds once frost danger has passed. Water well after planting and provide shade if transplanting in hot weather.
Larkspur Flowering Period
Annual Larkspur Bloom Season
Annual larkspur blooms in early summer in most climates. Here are guidelines for bloom times after spring planting:
– Rocket larkspur – Early June
– Giant Imperial – Early to mid June
– Blue Cloud – Mid June
– Carmine King – Mid to late June
– Pink varieties – Late June to early July
Expect larkspur started from seed in fall to bloom the following summer, usually 1-2 weeks later than spring plantings.
Perennial Larkspur Bloom Season
Perennial larkspur blooms later than annuals, depending on variety. Here are bloom period guidelines:
– Magic Fountains – Early summer (June)
– Liberty Series – Early to mid summer (June to July)
– Gold Medal hybrids – Mid to late summer (July to August)
– Tall varieties like Guardian – Midsummer (July)
The bloom period for perennial larkspur started from seeds in spring is typically mid to late summer. For plants started in fall, expect blooms the following early summer. Deadheading spent blooms can prolong flowering.
Care of Larkspur
Caring properly for larkspur ensures healthy, vigorous plants and maximum flowers. Here are tips:
Watering
– Keep soil consistently moist after planting seeds until they sprout.
– Water established plants 1 inch per week. Increase water in hot weather.
– Avoid wet foliage, which encourages disease. Water at soil level.
Fertilizing
– Apply balanced fertilizer when plants are 6 inches tall.
– Repeat every 4-6 weeks during active growth and blooming.
– Avoid high nitrogen fertilizers which cause excess foliage growth.
Pruning
– Deadhead spent blooms to encourage reblooming.
– Cut back leggy plants by 1/3 to encourage bushy growth.
– Remove yellowing leaves and stems as needed for neat appearance.
– Cut back perennials to 6 inches after frost kills foliage.
Overwintering Perennials
– Mulch perennial larkspur with 2-3 inches of bark, leaves or straw over winter.
– In very cold zones, grow in pots and overwinter indoors until spring.
– Cut back dead growth in early spring as new growth appears.
Troubleshooting Problems
Here are solutions for common larkspur growing issues:
Seeds Don’t Sprout
– Ensure soil stays evenly moist after planting for proper germination.
– Sow a second batch of seeds in case the first doesn’t sprout.
Foliage Yellows
– Yellow lower leaves often indicates overwatering. Allow soil to dry between waterings.
– Applying fertilizer may provide missing nutrients and green up plants.
Leggy Growth
– Pinch or cut back leggy plants by 1/3 to encourage bushy growth.
– Grow in full sun to discourage leggy stretching for light.
Powdery Mildew
– Improve air circulation with proper spacing and pruning.
– Avoid wetting foliage when watering which spreads spores.
– Remove and destroy badly infected plants to prevent spreading.
FungalStem Rot
– Improve drainage and avoid overwatering which encourages fungi.
– Space plants properly to allow air circulation.
– Remove and destroy infected plants. Do not compost diseased debris.
Conclusion
Larkspur is a rewarding flower to add to gardens, offering tall colorful blooms that attract pollinators. With proper planting techniques and care, both annual and perennial larkspur will flourish. Keys to success include sowing seeds at the right time for your climate, practicing proper planting and care, and avoiding overwatering. Apply these tips to enjoy the beauty of larkspur from early summer until frost.