How to Grow Delphinium Flowers

Delphinium Flowers

About Growing Delphinium Flowers in Your Home Garden

Growing Delphinium flowers in your backyard will reward you with absolutely gorgeous blooms year after year. There are both annual and perennial members of this tall and showy flower family. These spiked flowers originated in Europe and are found naturally in forest clearings. They’re an old-fashioned favorite. Gorgeous flower spikes come in jewel-like shades of blue, lavender, and diamond-bright white, some with darker center spots. Delphiniums are great as cut flowers. They look great in vases and indoor floral arrangements.

With many varieties in this family, Delphinium plants range in size from about one foot to several feet.

Caution: All parts of Delphinium are poisonous and could be fatal. If you have children or pets, you might want to steer clear of this flower.

Flowers Bloom: Spring to early summer.

Flower Colors: Colors include Blue, pink, purple, and white.

Plant Height: Plants grow up to 6 feet, depending upon variety.

Annuals and Perennials, Ranunculaceae

Delphinium Plant Propagation

Delphinium is started from seed. Sow Delphinium seeds directly into your flower garden after all danger of frost. Also, the seeds can be broadcast-spread around fields as a wildflower.

Sow Delphinium seeds early in the season and cover lightly with 1/8″ of garden soil. Space them 4 inches apart and thin seedlings to 1 1/2 feet apart.

Delphiniums are Rhizomes. You can separate the rhizomes of established plants and replant them in new areas.

Final Plant Spacing: Plant Dame’s Rocket 18″ apart. The plants tolerate a little crowding.  They look their best growing in showy groups. 

Days to Germination: 14 – 21 days.

How to Grow Delphinium Flower Plants

Delphinium plants like full sun to partial shade. They are very easy to grow and grow rapidly.

The plants do well in average soils and in cool weather. The soil needs to be kept moist to fuel their quick growth.

Water them during dry periods, once or twice per week.

Add a general-purpose fertilizer once a month until after they have bloomed.

Cut blooms just before they peak. Place in a vase and arrange with other flowers, or alone by themselves.

Important: As was previously stated, the plant is poisonous. Keep children and pets away from this plant.

Once your Delphinium is established, they will grow well until the first frost. Annual varieties of Delphinium will succumb to a hard frost or freeze. For perennial Delphinium varieties, cut them down to the ground after the plants have died off for the season. Perennial varieties do not require mulching or other winter protection in most areas. 

Ideal Soil pH: 6.5 – 7.0.

Also, see:

Plant Problems – Identify the causes and find the cures.

Insects and Plant Disease

Fungal disease is common, most notably Sclerotium rot which yellows leaves and wilts the plant. Delphinium is also affected by mildew. Treat affected plants immediately with a general-purpose fungicide. Also, remove seriously diseased plants to keep the disease from spreading.

Insect problems are less frequent. Organic or chemical insect repellents are effective against most pests.

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