Hardiness: USDA Zone 3a: to -39.9 °C (-40 °F) USDA Zone 3b: to -37.2 °C (-35 °F) USDA Zone 4a: to -34.4 °C (-30 °F) USDA Zone 4b: to -31.6 °C (-25 °F) USDA Zone 5a: to -28.8 °C (-20 °F) USDA Zone 5b: to -26.1 °C (-15 °F) USDA Zone 6a: to -23.3 °C (-10 °F) USDA Zone 6b: to -20.5 °C (-5 °F) USDA Zone 7a: to -17.7 °C (0 °F) USDA Zone 7b: to -14.9 °C (5 °F) USDA Zone 8a: to -12.2 °C (10 °F) USDA Zone 8b: to -9.4 °C (15 °F)
Sun Exposure: Full Sun
Danger: All parts of plant are poisonous if ingested
Bloom Color: Pink Blue-Violet Violet/Lavender White/Near White
Bloom Time: Mid Summer Mid Fall
Other details: Average Water Needs; Water regularly; do not overwater
Soil pH requirements: 6.1 to 6.5 (mildly acidic) 6.6 to 7.5 (neutral) 7.6 to 7.8 (mildly alkaline)
Patent Information: Non-patented
Propagation Methods: By dividing the rootball From herbaceous stem cuttings Allow cut surface to callous over before planting By air layering
Seed Collecting: Allow pods to dry on plant; break open to collect seeds Seed does not store well; sow as soon as possible
Park's Success with Seeds (1978) further notes that seeds of delphinium have a short-term viability, so should not be stored, but sown as fresh as possible. Also, that seed should be covered as they require darkness to germinate.
From a source I can't remember: If you're sowing seed in the summer, it might help to refrigerate the seed a couple of weeks before sowing to facilitate germination.
Ours was grown from seed by methods #1 & 3 above in summer a few years ago, and in spite of only getting half a day's sun "thanks" to a monster silver maple, has been a great time machine taking us back to by-gone times, coming up through rue, southernwood and yellow roses.
On Nov 9, 2004, lmelling from Ithaca, NY (Zone 5b) wrote:
I have delphiniums growing all over in various gardens around our property. Wonderful short-lived perennial that I grow for use in dried arrangements (and just to enjoy them nodding in the breeze!).
I grow several types: Black Knight and Round Table mixture being the most prevalent in my garden and have colors like deep blue with white or black bees, lavendar, violet, white and pink. Although for drying I prefer the dark blue, the violet/lavendar are probably my favorite - so delicate yet just awesome in color.
They grow well in full sun here in zone 5, in well drained soil. Very hardy - have lived through winters with no protection (mulch) down to -25 degrees and come back like gangbusters. If cut back after first flowers, will comeback to rebloom all the way until frost. Some powdery mildew problems so make sure and discard all leaves and stems when you cut back or cut down for the winter.
Deer resistant for me, however, a friend that lives a few miles away reported that deer ate all of her blooms in one night. Guess it just depends on taste! I was very surprised to hear this as I believed this plant would be toxic to deer as well.
this plant is a great addition to any garden. it is so pretty when several spikes are in bloom at the same time. and if you look at the picture i summited it is not that color. it is a pale blue, something messed up with the program i was using. GO VOLS!!!!!!!!!
On Jun 5, 2002, lupinelover from Grove City, OH (Zone 6a) wrote:
Can I give this a strong positive and a strong negative? Strong positive when plant has survived to at least 3 years old: the clumps become regal-sized, many flowering stalks. Usually dies after that in most of US leaving severe depression, and a big hole in the border. "My delphiniums!" is a cry often heard.
On Mar 12, 2001, Terry from Murfreesboro, TN (Zone 7a) wrote:
This clump-forming perennial is the tall, regal, early-blooming garden plant that most people think of when they hear delphinium. This lovely plant is often described as "stately." Blooming spires of rich blues, pale purples, bright whites, pinks, yellows, or reds bloom from early to mid-summer. The leaves are divided, lobed, and are medium to bright green.
The name comes from the Greek delphis, meaning dolphin. Ancient Greeks thought the shape of the flower bud resembled that of a dolphin.
This plant has been said to grow in the following regions:
Duarte, California El Cajon, California Richmond, California Machesney Park, Illinois Mount Prospect, Illinois Ellicott City, Maryland Dearborn Heights, Michigan Midland, Michigan Bay Head, New Jersey Cayuga Heights, New York Lebanon, Pennsylvania Edgewood, Washington Redmond, Washington Seattle, Washington Vancouver, Washington Appleton, Wisconsin