Delphinium

Why Should I Grow Delphinium?

Growing delphiniums in your garden can be a delightful choice for several reasons:

Striking Appearance: Delphiniums are known for their tall, spiky blooms, making them stand out in any garden setting. Their vibrant shades of blues, purples, pinks, whites, and yellows can add a pop of color to your landscape.

Vertical Interest: Their tall spires provide essential vertical elements in garden design, which can create depth and layers in flower beds, drawing the eye upward.

Pollinator-Friendly: Delphiniums attract a variety of pollinators, including bees, butterflies, and hummingbirds. By planting them, you’re supporting local biodiversity and aiding in pollination.

Cut Flower Garden: Delphiniums make exquisite cut flowers, maintaining their vibrancy and structure in floral arrangements. They can be the focal point of bouquets or provide height and background to other blooms.

Classic Appeal: Associated with cottage garden charm, delphiniums have a timeless appeal. They can evoke a sense of nostalgia and classic elegance.

Diverse Varieties: There’s a delphinium for almost every garden setting, from dwarf varieties suitable for smaller spaces or containers to towering giants perfect for the back of a border.

Deer and Rabbit Resistant: Given their inherent toxicity, delphiniums are usually not the first choice for browsing deer or rabbits, potentially saving gardeners from the heartbreak of chewed plants.

Seasonal Bloomer: With proper care, deadheading, and sometimes a little luck, delphiniums can provide a secondary bloom later in the season, extending their showcase in the garden.

Sense of Achievement: Delphiniums can be a bit finicky, requiring good drainage, protection from strong winds, and vigilant monitoring for pests. However, when they bloom in all their splendor, they offer a gardener a satisfying reward for their effort and care.

Popular Delphinium Varieties

Delphiniums are celebrated for their spires of colorful flowers. Many popular species and varieties belong to the “Elatum Group” of delphiniums, which includes tall, stately plants primarily cultivated in British and New Zealand breeding programs. Here are some of the most popular species and their notable varieties:

Delphinium elatum (Candle Larkspur)

• ‘Black Knight’: Dark violet flowers with a black, central bee.
• ‘Blue Lace’: Sky blue flowers with a light central bee.
• ‘Pacific Giants’: A series with a range of colors, including blue and purple.
• ‘King Arthur’: Vibrant purple blooms with a white bee.

Delphinium grandiflorum (Chinese Larkspur)

• ‘Blue Butterfly’: Compact variety with bright blue flowers.
• ‘Summer Nights’: Deep blue flowers on compact plants.

Delphinium belladonna (Belladonna Delphinium)

• ‘Bellamosum’: Features rich, deep blue flowers.
• ‘Cliveden Beauty’: Sky-blue flowers.

Delphinium New Millennium Series (Hybrids)

• Bred in New Zealand, this series offers plants with strong stems and resistance to disease. They come in a variety of colors, including lavender, blue, pink, and white.

Delphinium Magic Fountains Series

• A more dwarf variety, ideal for those who love delphiniums but lack space for the towering traditional types. They come in shades of blue, pink, and white.

Delphinium Guardian Series

• Known for early blooming, they are available in colors like lavender, blue, and white.

Delphinium exaltatum (Tall Larkspur)

• A North American native, this species produces blue-violet flowers.

There are numerous other hybrids and series developed by breeders, especially in places like the UK and New Zealand. When choosing a variety for your garden, consider factors such as size, color, and bloom time, as well as local climate and soil conditions.

Garden Design with Delphinium

Delphiniums are classic cottage garden plants, boasting towering spires of flowers that lend an air of grace and elegance to any garden. Their vertical growth habit makes them particularly useful in garden design. Here are ways you can incorporate delphiniums into your garden design:

Focal Points: Use tall varieties as show-stopping focal points in the center or back of garden beds, where they can rise above other plants.

Borders: Line the back of borders with delphiniums, allowing their height to frame and provide a backdrop for shorter plants in the forefront.

Companion Planting: Delphiniums pair beautifully with roses, peonies, and foxgloves, offering complementary shapes and colors. Their spiky form contrasts wonderfully with the mounded or wispy forms of other plants.

Container Gardening: Some compact varieties can be grown in containers to grace patios or balconies.

Cut Flower Gardens: Given their tall, sturdy stems and vibrant colors, delphiniums are ideal for cut flower gardens. The Guardian Series is particularly suited for this purpose.

Wildlife Gardens: Delphiniums can attract bees, butterflies, and other pollinators, making them a good fit for wildlife gardens.

Naturalistic Planting: In larger landscapes, allow delphiniums to naturalize in meadows or along wood edges, mingling with grasses and other wildflowers.

Structured Symmetry: For a more formal garden, plant delphiniums symmetrically on either side of a path or entryway.

Seasonal Highlights: Delphiniums bloom mainly in early to mid-summer. Pair them with plants that have a similar bloom period, or use them to bridge the gap between spring and late-summer bloomers.

Delphinium elatum

Delphinium hybrid

Remember, while delphiniums offer great height and color, they can be a bit top-heavy, especially in windy locations. It’s a good idea to provide them with some support, such as stakes or grow-through plant supports, to keep them upright and looking their best.

Incorporating delphiniums into your garden design will not only add vertical interest but also bring a touch of timeless elegance and charm to your outdoor space.

Companion Plants

Delphiniums are a popular choice for many traditional and cottage-style gardens. When paired with the right companion plants, they create a harmonious blend of colors, textures, and heights that can make any garden bed or border come alive. Here are some of the best companion plants for delphiniums:

Roses: The classic form and color of roses complement the tall spires of delphiniums. Together, they evoke the charm of an old-fashioned English garden.

Foxgloves (Digitalis): Both delphiniums and foxgloves have tall, spiky blooms that complement each other well, especially when their colors are coordinated.

Peonies: The big, lush flowers of peonies provide a lovely contrast to the slender spires of delphiniums.

Lupines: With similar tall, spiky blooms, lupines and delphiniums can create a dramatic vertical display in the garden.

Irises: The unique shape of iris blooms and their broad, strap-like leaves provide contrast against the backdrop of delphiniums.

Salvia: Salvia makes a captivating companion for Delphinium, enhancing the garden with its contrasting textures and colors, creating an eye-catching floral duo.

Yarrow (Achillea): The flat-topped blooms of yarrow, especially in soft pastels, make a lovely counterpoint to the vertical spires of delphiniums.

Phlox: The clustered flowers of phlox offer a textural contrast, and their blooming period can extend the color show in the garden.

Lady’s Mantle (Alchemilla mollis): The soft, rounded leaves and delicate green-yellow flowers of lady’s mantle offer a lovely contrast to the bold spires of delphiniums.

Shasta Daisies: Their bright, daisy-like flowers and mounded form offer a cheerful contrast to the vertical lines of delphiniums.

Columbines (Aquilegia): These spring bloomers have delicate, nodding flowers that can play off the bolder delphinium blooms.

Astilbe: Their feathery plumes in shades of pink, red, or white complement the delphinium’s vertical presence.

Ornamental Grasses: Tall grasses, like switchgrass or fountain grass, add movement and textural contrast.

When designing with delphiniums and their companions, consider factors like sunlight requirements, soil preferences, and watering needs to ensure that all plants thrive together. Additionally, stagger plants with varying bloom times to extend the season of interest in the garden.

Growing Tips

Growing delphiniums can be rewarding, as these plants offer spectacular blooms in various shades, most notably brilliant blues, a rare color in gardens. Here’s a step-by-step guide on how to grow delphiniums:

Choose the Right Location:

• Delphiniums prefer full sun (minimum of six hours of sun a day) but can tolerate partial shade. In hotter climates, afternoon shade can help prevent the plants from getting scorched.
• Ensure good air circulation to reduce the risk of fungal diseases.

Prepare the Soil:

• Delphiniums thrive in rich, well-draining soil.
• Before planting, work compost or well-decomposed manure into the soil to boost its fertility.

Planting:

• Delphiniums can be grown from seed, but many gardeners prefer to start with young plants or divisions for quicker blooms.
• Dig a hole twice as wide as the plant’s root ball and as deep.
• Set the plant in the hole so the crown (where the roots meet the stem) is at soil level. Backfill with soil, gently firming it around the plant.
• Water thoroughly after planting.

Ongoing Care:

• Watering: Keep the soil consistently moist, especially during the growing season, but avoid letting it get soggy.
• Fertilizing: Use a balanced, all-purpose fertilizer in the spring and again in early-mid summer to promote vigorous growth and blooms.
• Mulching: Mulch around the base to conserve moisture and suppress weeds.
• Staking: Due to their height, many delphiniums require staking, especially in windy locations.
• Deadheading:  Removing spent blooms encourages the plant to produce more flowers and can prolong the blooming period.
• Pruning: Cut back the plant to its base after it has finished flowering to encourage new growth and a rebloom in late summer or fall. Cut back flower stalks in fall but leave the basal foliage.

Overwintering:

• In colder zones, mulch around the base of the plant in the fall to protect the roots from freezing temperatures.
• In the spring, remove old, dead growth to make way for new shoots.

Propagation:

• Every 2-3 years, delphiniums can be divided in early spring or fall. This not only produces more plants but rejuvenates older plants.

Tips:

• Delphiniums have a taproot, which means they do not like to be moved once established. Choose the planting spot carefully.
• They’re also relatively short-lived perennials. By dividing them or allowing them to self-seed, you can ensure their presence in your garden for years to come.

With proper care and attention, delphiniums can become a stunning focal point in any garden, impressing with their towering blooms and vibrant colors.

Pests and Diseases

Delphiniums are susceptible to several pests and diseases. Here are some of the most common ones:

Aphids: These small insects can suck the sap from the leaves and stems of delphiniums, causing stunted growth and distortion. They can be controlled by spraying the plant with a strong jet of water or by applying insecticidal soap.

Crown rot: This fungal disease causes the base of the plant to rot, which can lead to wilting and death. It is often caused by overwatering or poorly-draining soil.

Gray mold: It usually occurs during wet and humid weather conditions and can cause the leaves, stems, and flowers of the plant to turn brown and become mushy.

Leafminers: Delphinium leafminers are tiny larvae that can cause significant damage to delphinium leaves. These pests tunnel inside the leaves, leaving a trail of damage that can result in the death of the plant. The leafminers are typically light green and can be difficult to spot, but the damage they cause is visible as white or brown patches on the leaves.

Powdery mildew: This fungal disease appears as a white powdery coating on the leaves, stems, and flowers of delphiniums. It can be prevented by ensuring good air circulation around the plant and avoiding overhead watering.

Root rot: This can occur if the soil is too moist, causing the roots to rot and the plant to wilt.

Slugs and snails: These pests can chew holes in the leaves of delphiniums, especially in damp conditions. They can be controlled by handpicking or by applying slug and snail bait.

Spider mites: These tiny pests can cause yellowing and browning of the leaves of delphiniums. They can be controlled by spraying the plant with a strong jet of water or by applying insecticidal soap.

Regular monitoring and prompt action can help prevent and control these pests and diseases in delphiniums.

Frequently Asked Questions

Are delphiniums perennial or annual?

Delphiniums are primarily perennials, although there are some annual varieties. The most commonly grown garden delphiniums are perennial, returning year after year.

Do delphiniums like full sun or shade?

Delphiniums prefer full sun, especially in cooler climates. However, in areas with particularly hot summers, they can benefit from partial shade, especially protection from the intense afternoon sun.

How toxic is delphinium to humans?

Delphiniums are toxic to humans when ingested. They contain various alkaloids, which can cause nausea, abdominal pain, and more severe symptoms in higher amounts. It’s essential to avoid consuming any part of the plant and to exercise caution when handling, especially around children and pets.

How do you keep delphiniums blooming? To encourage delphiniums to produce a second flush of blooms:

• Deadhead spent flowers promptly. Once the primary bloom spike begins to fade, cut it back to just above a set of leaves. This can stimulate the plant to produce side shoots that will flower later in the season.
• After the initial spring bloom, a light application of a balanced fertilizer can boost energy for a second round of flowering.
• Remember, while the second bloom is typically not as tall or grand as the first, it can still add beauty to the garden.