Knowing when to plant larkspur seeds is the single most important factor for a stunning spring display. Get the timing right, and you’ll be rewarded with majestic spires of blue, pink, white, and purple. This guide gives you the clear, simple steps to ensure your larkspurs thrive.
Larkspurs are cool-season annuals that prefer to be sown in fall or very early spring. They need a period of cool, moist conditions to germinate and establish strong roots before the heat of summer arrives. Planting at the correct time mimics their natural lifecycle and leads to the tallest, most robust blooms.
When To Plant Larkspur Seeds
This heading is your golden rule. For most gardeners, the ideal time to sow larkspur seeds is in the fall. The second-best window is in very early spring, as soon as the ground can be worked. Your specific climate dictates which season is best for you.
Understanding Your Climate Zone
Your USDA Hardiness Zone is the key to perfect timing. Here’s how it breaks down:
- Zones 3-5 (Colder Winters): Plant in early spring. Sow seeds as soon as the soil is no longer frozen, typically 4-6 weeks before your last expected frost date. The seeds will germinate as the soil slowly warms.
- Zones 6-7 (Moderate Winters): You have the best of both options. Aim for a fall planting after the first light frost, usually late October to November. Seeds will lay dormant over winter and sprout very early in spring. You can also sow in early March.
- Zones 8-10 (Mild Winters): Fall planting is essential. Sow seeds from late October through December. They will germinate in the cool winter months and bloom in early to mid-spring before the summer heat intensifies.
The Fall Planting Advantage
If your climate allows it, fall sowing is superior for several reasons. The seeds undergo a natural cold stratification process over winter, which breaks their dormancy. This results in stronger, more uniform germination in spring. The plants get a head start, developing deeper roots. They often bloom earlier and grow significantly taller than spring-sown seeds.
Spring Planting as a Backup
Don’t worry if you missed the fall window. Spring planting still works well, especially in colder regions. The trick is to sow early. Larkspur seedlings are quite frost-tolerant. If you wait until the weather is warm, the seeds may not germinate well, and the plants will struggle with the coming heat.
How to Plant Your Larkspur Seeds: A Step-by-Step Guide
Larkspurs have a few specific needs during planting. Following these steps will give you the best results.
Step 1: Choose and Prepare the Site
Larkspurs need full sun—at least 6 to 8 hours of direct light daily. They prefer rich, well-draining soil. Before planting, loosen the soil to a depth of about 12 inches. Mix in some compost or aged manure to improve fertility and drainage. Remove any weeds or large stones.
Step 2: Sow the Seeds Correctly
Larkspur seeds need darkness to germinate. Here’s the process:
- Scatter the seeds lightly over the prepared soil surface. You can also sow them in rows if you prefer a more organized look.
- Gently press the seeds into the soil with your hand or a board. Do not cover them with soil; they need light to germinate properly.
- Water the area gently with a fine mist to settle the seeds without washing them away.
Step 3: Initial Watering and Care
Keep the soil consistently moist but not soggy until germination, which usually takes 14-28 days. A light layer of fine mulch or straw can help retain moisture. Once seedlings are a few inches tall, you can thin them to about 8-12 inches apart to allow for good air circulation.
Essential Care for Spring Blooms
After germination, larkspurs are relatively low-maintenance. Consistent care ensures those optimal spring blooms.
- Watering: Water seedlings regularly. Mature larkspurs are somewhat drought-tolerant but perform best with about 1 inch of water per week during dry spells.
- Fertilizing: A light application of a balanced, slow-release fertilizer in early spring can boost growth. Avoid high-nitrogen fertilizers, which promote leafy growth at the expense of flowers.
- Support: Tall varieties may need staking, especially in windy areas. Install small stakes or grow-through supports early in the season.
- Pest Watch: Keep an eye out for slugs and snails on young seedlings. Aphids can sometimes be a issue later on; a strong spray of water usually dislodges them.
Common Mistakes to Avoid
Even experienced gardeners can make a few errors with larkspur. Here’s what to watch for:
- Planting Too Deep: Covering the seeds with soil is the most common reason for poor germination. Remember, they need light.
- Waiting Too Long in Spring: Sowing when temperatures are consistently above 65°F (18°C) leads to poor results.
- Overcrowding: Skipping the thinning step results in weak, spindly plants that are more susceptible to disease.
- Wrong Location: Too much shade leads to leggy growth and few flowers. Ensure they get plenty of sun.
Encouraging More Blooms and Saving Seeds
To prolong the bloom period, deadhead spent flowers by cutting the stalk back to a side shoot or leaf. If you want larkspurs to self-sow for next year, leave the last few flower spikes on the plant to mature and drop seed. You can also collect seeds yourself once the pods turn brown and dry. Store them in a cool, dry place for planting next season.
FAQ: Your Larkspur Questions Answered
Can I start larkspur seeds indoors?
It’s possible but tricky. Larkspurs have a taproot and dislike being transplanted. If you try, use deep, biodegradable pots and plant them out very early while the seedlings are small. Direct sowing is almost always more succesful.
Do larkspur seeds need cold stratification?
Yes, they benefit from it. Fall planting provides this naturally. For spring planting, you can mimic this by placing seeds in a damp paper towel in a plastic bag in the refrigerator for 1-2 weeks before sowing.
How long do larkspurs bloom?
With proper care and deadheading, you can expect several weeks of bloom in spring, typically from late spring into early summer, depending on your climate and when you planted.
Are larkspurs the same as delphiniums?
They are closely related but different. Larkspurs (Consolida) are annuals with more finely cut leaves and smaller, clustered flowers. Delphiniums are typically perennials with larger flower spikes. Their care and planting times are very similar, though.
Why didn’t my larkspur seeds come up?
Besides planting depth and timing, old seeds can be a culprit. Larkspur seed viability declines after a year or two. Always use fresh seed from a reputable source for the best germination rates. Also, ensure the soil stayed consistently moist after sowing.
Timing is everything with these beautiful flowers. By sowing your seeds at the right moment—whether in the crisp days of fall or the first thaw of spring—you set the stage for a spectacular garden performance. With their elegant height and captivating colors, larkspurs are worth the little bit of planning they require. Follow this guide, and you’ll have a garden filled with the classic charm of larkspur blooms when spring arrives.