Delphinium

DelphiniumShowy spikes and beautiful colors — even blue — make delphinium a favorite focal point in many gardens.

Sunlight: Full sun to partial shade
Maturity: 85-125 days from seed to flower
Height: 2 to 6 feet
Spacing: 12 to 36 inches apart in all directions

Native to England, home flower gardeners are growing delphinium — also known as larkspur — for their beautiful feathery leaves and tall spires of blossoms that bloom all summer long. Available in almost every color, they add grace to borders and are spectacular when planted along a stone wall or garden fence.

Delphiniums can be difficult to grow even under the best of conditions. However, both tall and short varieties have long been a favorite in cottage-type gardens, mixed perennial beds and floral bouquets. Impressive plants with showy single or double flowers grow up to 6 feet tall. Short-lived perennial.

Site Preparation:

These “needy” plants do best in sunny locations with rich, well-drained soil. Prior to planting, work a couple shovelful of organic compost and a dry fertilizer into the soil. This helps condition the soil, which improves drainage and will keep roots cool (watch 6 Tips for Growing Great Flowers – video).

Delphiniums are one the first perennials to show new growth in the spring and can tolerate some frost. Large varieties will require support and protection from the wind. Plants do not like hot weather and dry conditions.

Tired of the same old flowers? Heirloom flower seeds — the ones that Grandma used to grow — add charm to your garden while stirring memories with their abundant blossoms and arousing scents. Best of all, we ship them FREE!

How to Plant:

May be propagated from divisions or from seed. If planting from seed, sow outdoors two weeks before the last frost, just beneath the soil surface (see Sowing Seeds Directly In the Garden). Seeds will germinate in 14-21 days.

Tip: Chill delphinium seed for a week prior to planting to improve germination — stick them in the refrigerator.

If propagating by division, separate clumps every 2-4 years in early spring. Delphinium will benefit from the cool, wet weather and be well established before the heat of the summer kicks in.

Note: Most perennial flowers benefit from division as they get older and begin to lose vigor, plus you get more plants to spread around the garden or share with friends.

Water well throughout the gardening season and feed with a liquid flower fertilizer to keep plants strong and productive. Pinch off the faded blossoms to extend the flowering season. Mulch to prevent weeds, conserve moisture and improve aesthetics.

Insects and Disease:

Slugs and aphids will occasionally attack delphinium. Watch closely and apply diatomaceous earth or other OMRI listed pesticide, if aphids are found.

Large irregular holes in foliage and partially eaten seedlings are signs of slug damage. Scatter Sluggo, an organic iron phosphate bait, around plants to kill slugs and snails without harming people, pets or wildlife.

The leaves and stems of plants are also susceptible to attack by powdery mildew, rust and gray mold. To reduce common plant diseases found on delphinium:

  • Avoid overhead watering whenever possible
  • Properly space plants to improve air circulation
  • Apply copper and sulfur sprays to prevent further infection

Seed Saving Instructions:

Not available

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