I love the Ceratostigma plumbaginoides which also has nice fall foliage color. This is a new plant this year, but I've grown them in the past. Not a robust plant, at least not in my garden. It appears late in the spring and doesn't seem to compete all that well in my jungle. I'm trying this time to give it more of a chance by controlling the enthusiastic plants around it.

Hydrangea serrata 'Blue Billow' is another favorite.

Claire

Grape hyacinth fit the bill. I have two cultivars:

Christmas Pearl
{{gwi:2613}}

Valerie Finnis (for light blue)
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Bearded iris, dutch iris, bellflowers, delphiniums, lupine, salvia, clematis, speedwell, sea holly, and hyacinths all have cultivars that are a true blue. I have seen some cultivars of caryopteris that have what I consider to be blue flowers although some may say that they have some purple in them, too.

Balloon flower seems to be true blue to me. Love that lithodora though ... I might need to add one of those.

I had a blue allium, A. cerulean, but it disappeared. Shocking, really, most of them are impossible to kill.

Been a "blues" fan for years. . .in addition to those
mentioned, I'm a huge fan of Mertensia virginica
(such a vibrant blue in early Spring!), and then
Aconitum carmichaeli for statuesque Fall blue. . .
for the palest of blues, there's Amsonia hubrechtii,
and later in the season a shrubby (almost vinelike)
Clematis heracieifolia 'Davidiana'. . .I have it scrambling
up and through a pristine white David Austin rose, "Claire Austin", which really makes the blue stand out.
I also have Brunnera 'Jack Frost', Lobelia siphilitca and
Veronica 'Sunny Border Blue'. . .and,yes, I have a whole
section of my garden = some sun, some shade -devoted to "blues", heavily mixed with whites and pale yellows.

Carl

Like Carl I have gardens that are predominately blue (though they include blue-purples as well) with highlights of white and yellow.

Evovulus glomerata is a tender perennial with true blue flowers that I grow in pots most years and often can winter over indoors.

Some of my Pulminaria look true blue to me.

I have grown one of those quite short, bright blue delphiniums that seems either not hardy or blooms itself to death in one year, perhaps Magic Butterflies(?)

Some of the other flowers listed by previous posters look blue to me, but others seem more purple-blue to me. It may be a combination of the particular selection that is being grown along with growing conditions such as sun amount and soil pH. It also may be a function of how each of us perceive color. There have also been a couple of threads on blue flowers in the perennials forum.

Here is a link that might be useful: one Perennials thread on blue flowers

nhbabs: The evolulus glomerata looks interesting, but
I can't seem to find any sources. . .do you get it from a local nursery, online, or perhaps grow it from seed?

Carl

nhbabs,
I agree about many so-called 'blue' flowers being more violet than blue. I would say that the well-known morning glory 'Heavenly Blue' is what I consider true blue, and maybe Amsonia or the light blue grape hyacinth for lighter blue. And there were some others that some members mentioned here as well. I was also wondering if there's a perennial vine that has blue flowers. I looked at some of the Clematis mentioned here, but again they seem to be more violet than blue.

{{gwi:5901}}

I think the problem here is two-fold. First, blue is in the eye of the beholder at least in some cases. The vision of some people is much more sensitive to color than others. Secondly, the color you see can change with the surroundings. Have you ever looked at a paint swatch and it looked blue until you held it up to another paint swatch that was even more blue and now the first one looks purple. I think the same concept applies to flowers. Not to mention, the actual color can greatly depend on the soil condition and the nutrients available to the plant. Shopping for certain colors online can be an exercise in frustration because of all the doctored pictures online. Just look up the Clematis cultivars, Rhapsody, Durandii, and Blue Light and behold the spectrum of colors that you will see. Who knows which one is correct.

Also, in the past I have run into some very technical photographic discussions about how to photograph blues so they show up true to color. Back in the dark ages, a lot of iris growers had a dedication to Fuji film because they thought it caught blues better. Since then, I've heard similar discussions regarding brands of digital cameras.

I use a Fuji camera precisely for that reason. I have years of photography experience, coming from the days of my darkroom into the very earliest digital cameras and continuing to now. I have found that Fuji digital cameras give the most accurate color reproduction, certainly for flowers, and the greens are very accurate. Having said that, I still think that most people seeing the actual flower, as opposed to a photo in a catalog or even online, would agree that "Heavenly Blue" morning glories really say "blue", as does the Meconopsis (Himalayan poppy), Lithodora and some others that were mentioned in this thread.

{{gwi:5901}}

Carl - I first was introduced to Evovulus by a local NH nursery, but they unfortunately stopped carrying it several years ago. The last couple of years I have bought it from Avant Gardens, a mail order and bricks and mortar nursery in North Dartmouth, MA. They list it under 'Annuals/ Tender Perennials'. I really appreciate the variety of plants which they carry.

I have also grown a couple of Salvias that were a true bright light blue, but off the top of my head I can't remember the species. They were tender perennials, perhaps hardy to zone 7 if I recall correctly.

Over the years, some of the Linum (flax) I have grown has been blue, while some has had purple tones to the blue.

Here is a link that might be useful: Avant Gardens

I love blue, but it's such a difficult color to achieve in the garden. And it's so true that the idealization of "blue" is a personal thing. I'm sure that a plant is blue until I see it next to something else.

I've found that the appearance of the blue is also affected by the light on the plant. For example, my 'Blue Paradise' Phlox only looks close to blue early in early morning, but as the sun comes across the yard, it quickly fades to purple. My H.F.Young Clematis is kind of blue -- again, the kind that fades in the sun, though its first flush in the spring is wonderful. I did put in some Lithodora after seeing Bill's and hope that these come back next year.

Last year I added Eryngium 'Big Blue' to the long garden and it was spectacular. Now I have to just wait and see if it survived the salt water that flooded my gardens this fall. I also planted a 'Blue Moon' Wisteria and will see what that does this season. I'm thinking it will also be more purple.

Some of my favorite 'blue-to-me' flowers are Salvia azurea var grandiflora/Pitcher Sage, Salvia patens/Gentian Sage, Cynoglossum amabile/Chinese Forget-Me-Not 'Firmament', Anchusa capensis 'Blue Angel', Anagallis monellii/Pimpernel, Lathyrus sativus/Grass Pea, Centaurea/Cornflowers, Myosotis. I also love 'Heavenly Blue' & 'Blue Star' morning glories and 'Cliveden Beauty' & 'Blue Butterfly' delphiniums. Oh, and Nemesia 'KLM' is very cute.
That Lithodora is gorgeous...I want it!
The link below is a source for Evolvulus.
(pic of my Pitcher Sage)

Here is a link that might be useful: Evolvulus

This post was edited by jaynine on Sun, Feb 17, 13 at 18:17