How to Grow Delphinium in Missouri

Delphiniums are stunningly beautiful flowers that can add a touch of elegance and color to any garden. Known for their tall spikes of vibrant blooms, these perennials are a favorite among gardeners looking to create a visually striking landscape. Growing delphinium in Missouri can be a rewarding experience, but it requires some knowledge of their specific needs and conditions. In this article, we will explore the best practices for growing delphinium in Missouri, including site selection, soil preparation, planting techniques, care, and pest management.

Understanding Delphinium

Before diving into the specifics of growing delphinium, it’s essential to understand this plant. Delphiniums belong to the Ranunculaceae family and come in various species and hybrids, with flower colors ranging from blue to purple, pink, and white. They typically bloom in late spring to early summer, providing a burst of color when many other plants are just starting to come into bloom.

However, delphiniums can be somewhat challenging to grow, especially in regions with hot summers like Missouri. Understanding their growth habits and environmental preferences will help ensure a successful gardening venture.

Selecting the Right Variety for Missouri

When choosing delphinium varieties to grow in Missouri, consider your specific climate zone. Missouri is primarily in USDA hardiness zones 5b to 7a. Some recommended varieties that thrive in these zones include:

• Delphinium elatum (Tall Garden Delphinium): These are famous for their tall stature and large flower spikes.
• Delphinium grandiflorum (Chinese Delphinium): This variety is shorter and more manageable for smaller gardens.
• Pacific Giants: A hybrid cultivar known for its impressive height and rich colors.

Select varieties based on your garden’s conditions and your personal aesthetic preferences.

Choosing the Right Location

Delphiniums thrive in full sun or partial shade. When selecting a location in your garden, aim for an area that receives at least 6 hours of direct sunlight each day. Morning sun is particularly beneficial as it helps dry the leaves quickly, reducing the risk of fungal diseases.

Soil Requirements

Delphiniums prefer well-drained, fertile soil with a pH between 6.0 and 7.0. Before planting, conduct a soil test to assess nutrient levels and pH. Based on the results:

• Amend your soil: If your soil is heavy clay or compacted, consider adding organic matter such as compost or well-rotted manure to improve drainage and nutrient content.
• Improve drainage: If you have concerns about drainage, you can create raised beds or mounds where delphiniums can grow without sitting in waterlogged conditions.

Planting Delphiniums

Timing: The ideal time to plant delphiniums in Missouri is in early spring after the last frost date or in late fall before the ground freezes.

Starting from Seeds

1. Seed selection: Choose high-quality seeds from reputable suppliers.
2. Indoor sowing: Start seeds indoors about 8-10 weeks before the last frost date.
3. Germination: Sow seeds in seed-starting mix and keep them moist but not soggy. Seeds may take 14-30 days to germinate.
4. Transplanting: Once seedlings have several leaves and outdoor temperatures are consistently above freezing, transplant them outdoors.

Direct Sowing

If you prefer direct sowing:

1. Choose a sunny location with well-prepared soil.
2. Sow seeds directly on the surface of the soil in early spring.
3. Lightly cover them with soil or vermiculite; they require light for germination.

Caring for Delphiniums

Once planted, delphiniums require consistent care to thrive.

Watering

Delphiniums need regular watering to establish their root systems and during dry spells:

• Water deeply but infrequently, allowing the top inch of soil to dry out between waterings.
• Avoid overhead watering if possible; focus on watering at the base of the plant to reduce disease risk.

Fertilization

To promote healthy growth and abundant flowering:

• Apply a balanced fertilizer (like 10-10-10) at planting time.
• Follow up with a light feeding every 4-6 weeks during the growing season.

Staking

Due to their height, many delphinium varieties may require staking:

• Install stakes when plants reach about 12 inches tall.
• Use soft ties or twine to secure stems gently without damaging them.

Pruning

Regular pruning helps maintain plant health:

• Deadhead spent flowers throughout the season to encourage additional blooms.
• In late summer or early fall, cut back any spent foliage to promote healthy growth next year.

Managing Pests and Diseases

Delphiniums are generally hardy but can be susceptible to certain pests and diseases:

Common Pests

1. Aphids: Small insects that suck sap from young growth; control them using insecticidal soap or neem oil.
2. Slugs and Snails: These can harm young plants; use traps or barriers (like crushed eggshells) to deter them.

Common Diseases

1. Fungal diseases: Powdery mildew can occur in humid conditions; ensure good air circulation by spacing plants correctly and watering at the base.
2. Botrytis blight: This fungus thrives in damp environments; remove affected plant parts promptly and avoid overhead watering.

Winter Care for Delphiniums

In Missouri winters, it is crucial to protect your delphiniums:

1. Mulching: Apply a thick layer of mulch around the base of plants in late fall to insulate roots from freezing temperatures.
2. Cutting Back: After frost has killed the foliage, cut back stems to about 2 inches above ground level.

Conclusion

Growing delphinium in Missouri is an endeavor that combines beauty with a bit of challenge due to climate considerations. By selecting appropriate varieties, preparing suitable locations and soils, providing diligent care during their growing seasons, and implementing strategies for pest management, you can cultivate stunning delphinium plants that will grace your garden with their vibrant color year after year. Whether you’re aiming for a cottage garden look or want dramatic vertical color accents, delphiniums can elevate your landscape design while rewarding you with their captivating blooms each summer. Happy gardening!