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Delphinium Flowers: Sow, Plant and Grow

Botanical Overview:

Delphiniums belong to the genus Delphinium, which is part of the Ranunculaceae family.

Delphiniums, with their majestic spikes of vibrant blooms have adorned cottage gardens for centuries, making them a great addition to any garden. Learn how to cultivate these flowers with our comprehensive guide, covering everything from planting instructions to maintenance tips. Delphiniums are self seeders and loved by a lot of insects.

In the language of flowers:

Delphiniums symbolize positivity, joy, and a sense of lightness. They are often associated with new beginnings and aspirations.

Delphinium elatum:

Height: 4-6 feet
Flower color: Blue, Purple, White, Pink. I see other colours being offered as well - like orange.
Description: Tall stately perennial with dense spikes with 2" wide flowers.
Culture: Full sun to partial shade. Rich, moist, well drained, slightly alkaline soil'
Propagation: by division or seeds. May need staking and winter protection. I plant mine by roses bushes and I have a purple delphinium that likes growing up my pine tree. :)
Cut back after blooming to encourage more blooms
Hardy to: Zones 3 - 8.

Instructions that came with my seed packet:

  1. Start indoors about 8 weeks before last frost
  2. Sow seeds .03 cm deep - I just sprinkle my seeds on the soil - and dust the seeds with more soil.
  3. Keep soil evenly moist
  4. Seedlings emerge in 21-28 days
  5. Before transplanting, move to a sheltered area outside for a week.
  6. Set out in the garden 61 cm apart about 24 inches
  7. Blooms in early summer in about 180 days

Do you need to stratify Delphinium seeds?

I tried both - no difference.
In the garden - Delphiniums are perennials. So they drop their seeds. The seeds will stay dormant in the cold. So I guess it's natural stratification.
I have put my seeds in the fridge, some in the freezer and some I've sown right out of the package and no difference. They all grew.

Where is the best place to plant delphiniums?

I know the instructions says "full sun", I found my do better with bright light and some shade. Maybe I'm watering them enough, but the ones with shade from other plants are doing better.

Are Delphiniums invasive?

Where I live - "No!". If the flower stocks are left to dry, some of the seeds will sprout in the spring and the delphinum clump will get bigger, but because delphiniums are short lived perennial (2-3 years) I don't have a problem with them getting out of control.

Do I deadhead Delphiniums?

I do deadhead mine, if I don't need to harvest the seeds.
When I do deadhead my Delphiniums, I do get a second flush of flowers.

How long do perennial Delphiniums last in the garden?

Most only last 2 or 3 years in the garden.

What is the vase life of Delphiniums?

Vase life of Delphinium elatum hybrids is 5 to 7 days.

When to harvest Delphiniums for cut flowers?

Harvest stems early in the morning when blooms are fully open. Place cut stems immediately in water and store in a cool environment until needed to prolong vase life.

Maintenance and Pest Control:

Staking: due to their tall growth habit, delphiniums often require staking to prevent them from flopping over, particularly in windy conditions. Use bamboo stakes or other support structures to prop up the stems. I like tomato cages. When Delphiniums are grown it obscures the wire frame.
Pruning: Prune delphiniums after flowering to remove spent blooms and encourage a second flush of flowers. Cut the flower stalks down to the base of the plant, taking care not to damage emerging shoots.
Pest and Disease Management: Delphiniums are susceptible to pests such as aphids, slugs, snails and powder mildew. Monitor plants regularly.


Delphiniums are prized for their long, sturdy stems and vibrant colors, making them a favorite choice for floral arrangements and bouquets. They add height to the flower garden and insects and hummingbirds love them.

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