Blue Delphinium: Choosing and Growing True Blue Flower Spires in the Garden

Growing blue delphinium is on nearly every garden bucket list at one point or another. The towering spires of flowers in rich true blue, cheerful bright blue, and soft sky blue are a rare (and much anticipated) seasonal treat in cottage and border gardens. Here are 25+ varieties of blue delphinium, as well as tips for growing them in your garden.

Close up of blue bee delphinium flowers - cobalt dreams - new millennium

The Blue Delphinium

Blue delphiniums are the queens of the early-summer perennial border garden. These towering beauties can be grown at home from blue delphinium seeds of most varieties, and can also generally be purchased locally as seedling or clone plants.

The meaning of the blue delphinium is grace. Blue delphinium is a dignified, nearly-royal flower that’s perfect to celebrate a joyous occasion. Happily, delphiniums are the birthday flower of July, where they represent an open and loving heart.

“Glamourous and aristocratic delphinium spires come in colors not often seen elsewhere in the garden – most notably blues, including ultramarine, celestial, and iridescent examples.”

Martha’s Flowers: A Practical Guide to Growing, Gathering, and Enjoying, by Martha Stewart & Kevin Sharkey
stunning blue delphiniums

Blue Delphinium Varieties

Here are some of the best blue delphinium varieties. These hybrids are grouped by series, as some series families of delphinium have more than one blue variety.

“There are a few species groups of delphiniums. The Belladonna group includes blue or white flowers that grow 3 to 4 feet tall. You’ll find taller plants (3 to 8 feet) and more colors in the Elatum group.”

Martha’s Flowers: A Practical Guide to Growing, Gathering, and Enjoying, by Martha Stewart & Kevin Sharkey
blue delphinium - close up of flowers

New Millennium Delphiniums: Blue Hybrids

These cultivars from the stellar New Millennium series of hybrid delphinium come in blue shades:

New Millennium delphiniums are bred by Dowdeswell’s Delphiniums in Whanganui, New Zealand. I order mine from Phoenix Perennials here in Canada. In the USA they can be ordered from Nature Hills or Walters Gardens. Or ask your local garden centre to order them in for you!

“The delphiniums we breed and offer for sale are primarily Delphinium Elatum delphiniums. This is otherwise known as the tall, majestic English Delphinium Hybrid.”

About New Millennium Delphiniums, Dowdeswell’s Delphiniums

Blue Million Dollar Hybrid Delphiniums from Proven Winners

Here are two lovely blue delphinium (Delphinium elatum) plants from the Million Dollar series:

Million Dollar series blue delphinium types are offered by Proven Winners and can be ordered online or through local garden centers.

Pacific Giant Delphiniums (Blue Varieties)

These specific cultivars in the ever-popular Pacific Giant series of hybrid delphinium come in blue shades:

The Pacific Giant Delphiniums were developed in California by Frank Reinelt (read more from Thompson & Morgan on delphinium breeding).

Magic Fountains Series – Blue Dwarf Delphiniums

Magic Fountains delphiniums are dwarf versions of the Pacific Giant series. Here are some blue delphinium varieties from the Magic Fountains series:

Here is a guide to growing the dwarf Delphinium Magic Fountains Series from the RHS.

Belladonna Series – Blue Free-Form Delphiniums

Belladonna delphiniums are shorter than English hybrids and tend to have more space between the flowers on the stalks. Here are some Belladonna delphiniums with blue flowers:

  • Bellamosum Delphinium (deep blue)
  • World Peace Delphinium (deep blue)
  • Piccolo Delphinium (indigo blue)
  • Blue Bees Delphinium (sky blue)
  • Cliveden Beauty Delphinium (light blue)

Reference & More Info: Delphinium (Belladonna Group), Cornell University

dwarf blue delphinium - summer nights

Delphinium grandiflorum – Blue Varieties

Here are some additional blue-blooming Delphinium grandiflorum types:

Delphinium elatum (Blue Varieties)

These named cultivars of Delphinium elatum bloom in shades of blue:

“Of course, there are now extraordinary pinks and creams and lavenders, but I still melt when I observe a 3-footstalk of electric-blue flowers.”

Martha’s Flowers: A Practical Guide to Growing, Gathering, and Enjoying, by Martha Stewart & Kevin Sharkey
blue delphinium in garden
single blue delphinium flower in the garden
planting a blue delphinium in the cottage border garden

Planting Blue Delphinium in the Garden

Here are the basics for planting blue delphinium plants in your garden:

  • Delphiniums grow best in moist soil with moderate air temperatures.
  • Choose a planting spot with full sun that’s also shielded from wind.
  • Research the height of the plant and plan its location to accommodate its full height.
  • Plant the potted nursery plant in a wide hole, but not a deep hole.
  • The soil line of the potted delphinium should be level with the surrounding garden soil.
  • Water the plant thoroughly after planting.
  • Apply a nutrient-rich top-dressing of compost or organic fertilizer.
  • Cover the soil with an organic mulch to conserve soil moisture.

The video shown above is one I made showing how I plant delphiniums. I’m planting some of my favourite blue types in this video!

True blue delphinium flowers in garden

Growing Blue Delphinium Flowers in the Garden

Blue delphinium do require more maintenance than most other cottage garden perennials, but the effort is worth it for the beautiful blooms! Here are the basics for growing beautiful blue delphiniums in your garden:

  • Keep the soil consistently moist, but not soggy (or dry).
  • Water at the base of the plant and try to keep water off the leaves when possible.
  • A sprinkle of wood ash from the fire pit can help deter pests and disease.
  • Stake plants when they reach 12″ tall. Continue staking at 12″ intervals. I like to place the stakes behind each stalk to hide them as best as I can.
  • Expect blooms in June or July, generally following peony bloom season.

“This towering treasure makes a statement at the back of a mixed border, as a vertical accent or in a container. With dozens of blooms on each stem, it gives hummingbirds plenty of nectar sources to share with butterflies and other bugs, too.”

Gardening for Birds, Butterflies, and Bees: Everything you Need to Know to Create a Wildlife Habitat in your Backyard, by the Editors of Birds & Blooms Magazine
Blue Delphinium Plant - million dollar sky - hybrid bee delphinium
cobalt dreams blue delphinium
Delphinium “Cobalt Dreams” (New Millennium)

“There are very few true blue flowers in nature, so Delphinium ‘Cobalt Dreams’ stands out. Let the qualities that make the flower special in the garden – its height, color, and variety on the stem – be your guiding principles once you bring it inside, with arrangements that play to those strengths.”

Martha’s Flowers: A Practical Guide to Growing, Gathering, and Enjoying, by Martha Stewart & Kevin Sharkey
Blue Delphinium Plant - tag for Cobalt Dreams from New Millennium Delphinium Series
blue delphinium in bloom
‘Cobalt Dreams’ from the New Millennium Series (New Zealand) in bloom
Blue Delphinium Plant - Blue Lace Variety - New Millennium Series NZ
blue delphinium - dark blue delphinium flowers
Delphinium blue mirror

Mary Jane

Mary Jane is a home gardener who loves creating healthy, welcoming spaces (indoors and out!) - About Mary Jane (https://www.homefortheharvest.com/authors/about-mary-jane-duford/)

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