Planting, Growing, and Caring for Delphinium
Oh, the delightful delphinium! The stalwart of many summer flower gardens, these showy perennials are grown for their long, colorful spikes in blue and other gorgeous hues. Flowering all summer, delphiniums are butterfly and hummingbird magnets, too! Learn how to plant, grow, and care for delphiniums.
About Delphinium Flowers
Delphinium is a genus in the Ranunculaceae family. (They’re often confused with larkspur, which are a different plant species.) There are more than 300 delphinium species, so there is quite a variety of heights, from dwarf hybrids to 6-foot tall beauties, so they can be planted in the front, middle, or back of a perennial border. The blue delphinium is most common, but varieties also come in gorgeous shades of violet, pink, white, red, and purple. They are popular in both cottage-style and cutting gardens.
Most delphiniums are short-lived perennials, lasting 2 or 3 years in the garden. Some varieties will bloom throughout the entire summer if the plants are cut back regularly. Other hybrids bloom from early to mid-summer and will produce a second flower display in late summer or early fall if you cut off the old flower stalk.
What’s important to know about delphiniums is that they will thrive if you meet their specific conditions. Delphiniums prefer moist, cool summers; they do not fare well in hot, dry weather or sudden wind or rain, which can knock them down. Most varieties will need staking. See more details below.
Are Delphinium Poisonous?
Yes, delphiniums are highly poisonous. If seeds and seedlings are ingested, they can cause nausea, twitching muscles, paralysis, and even death. This is mainly a concern for grazing animals such as cattle, horses, and sheep, and it is also a caution to gardeners with small children.
Read Next
Growing
- Delphiniums are heavy feeders. Apply a balanced liquid fertilizer starting in early spring every 2 to 3 weeks.
- Insert sturdy stake supports no later than mid-spring or when the plants reach 12 inches high.
- Do not allow the soil to dry out, but avoid puddling. Water plants during the summer if rainfall is less than 1 inch per week.
- For ideal flower spikes, thin side shoots at 3 inches high, leaving 2 or 3 shoots on young plants and 5 to 7 shoots on mature, well-established ones.
- Deadhead by cutting spent flower spikes back to small, flowering side shoots.
- After delphiniums have finished blooming, cut flower stalks to the ground, and new, though smaller, flower stalks will develop. The flowers will survive the coming cold days and even light frosts. (See local frost dates.)
- Every 3 to 4 years, divide plants in spring: Remove and replant the new little plants growing around the outside of the clump. Discard the hard old heart.
Types
- Belladonna Group: blue flowers native to North America; easier to grow and longer-lived than varieties in the Elatum Group (below); upright, loose, and branching perennials; secondary flower spikes extend bloom period into autumn; 3 to 4 feet tall. ‘Blue Donna’ has clear, blue flowers.
- Elatum Group: tallest varieties in shades of violet, blue, pink, and/or white; short-lived; reach 6 feet tall or more. ‘Aurora Deep Purple’ has purple flowers with a white center.
- Pacific Hybrids: 3-inch violet, blue, and pink flowers; short-lived; tolerate warm/hot climates as annuals; giant (3- to 6-foot) heirlooms and dwarf hybrids. ‘King Arthur’, 5 to 6 feet tall, has plum flowers with white centers.
Gardening Products
More Like This
If your beautiful Blue has flowered once this season, you may have done a perfectly good thing; it may bloom again. We can't promise but cutting back after first bloom is frequently recommended. Fertilize her once again.
BTW, how far did you cut back: what do you mean by "completely"? It is advisable to cut only the flower stalk for reblooming.
This is usually an indication that the plant/s need to be staked. See here for advice and options for doing that:
http://extension.psu.edu/plants/gardening/fact-sheets/general-gardening/supporting-herbaceous-plants-in-a-flower-garden
First of all you need to get rid of your snail problem. You can buy snail and slug bait with iron phosphate, which is usually successful. Go to our slugs/snails page at http://www.almanac.com/content/slugs for more information about getting rid of snails.
If the roots are OK the delphinium will grow new leaves.
Hi, LuAnn,
These are nasty! But there is not much you/we can do. We mention handpicking and Sevin below. Here's a little more:
Our bast solution is actually a few we've researched. The University of California has several suggestions: http://www.ipm.ucdavis.edu/PMG/r52300311.html
This Colorado State pdf has several interesting pics and offers an array of deterents and worse for loopers on page 24 (the cabbage looper appears on p 15): http://webdoc.agsci.colostate.edu/bspm/Garden%20Caterpillars.pdf
A third solution seems to be self inspection and removal by hand, and explained here are neem (it stops them from feeding and so eventually they die), and suggests natural enemies: http://www.extension.umn.edu/garden/insects/find/caterpillar-pests-of-cole-crops-in-home-gardens/
If you happen on any additional or new sure-fire methods/ideas, please share!
- « Previous
- 1
- 2
- …
- 10
- Next »
Comments