After weeks of rain every day, fnally the sun came out. Looking out the kitchen window, I was awestruck at a big patch of sky-blue at the back of my garden. The bird's-eye speedwell (Veronica chamaedrys) had burst into bloom.
What is it about blue flowers that makes my heart sing? True blue, with no purple in it. It's not common while purple flowers are very common, perhaps because bees are attracted to that color.
On the Web I found lists made by admirers of true-blue flowers. But trying to share this passion with others runs into several snags. The same cultivar grown in different soil, with different food, or different weather ... can produce different tones. You can't depend on what the camera may capture, or on how a print is developed or what each computer uses for its rendition. Ultimately, what seems blue to me may betray a purple tone to you. (Or I may just be willing to settle for less.)
Pure blue in a flower is so uncommon, and so desirable, that growers and sellers often call them blue when they're obviously purple. For example there are several other good blue veronicas, but to my eye the popular tall variety "Sunny Border Blue" is unquestionably blue-purple. Cultivars of three different perennials hardy here are named "True Blue": a pansy, a spiderwort, and a primrose. I haven't seen them yet.
Species names sometimes refer to color: for example "caeruleum" (sky-like), "coelestinum" (heavenly), and "azureum" all tell you they're sky-blue. Somehow I trust the Latin name better than the commercial one. Also when I noticed that some flowers I've seen advertised as "blue," my plant encylopedia calls "purplish blue" ... that inclined me to trust the book.
I seldom grow annuals, but two blues persuade me: lobelia "Crystal Palace," such a deep, intense color no photo has ever captured it and borage, a bright, sparkling hue (and it often self-sows). Perennials which satisfy this craving for me: gentian, "Blue Sapphire" flax, Pitcher's sage, a few delphiniums.
Some I want to check out: Siberian squill "Atrocoerula" (a.k.a. "Spring Beauty"), and two late-bloomers Allium caeruleum and Ageratum coelestinum "Cori." There are also supposed to be some true-blue lupines, especially the natives. And "Amy Doncaster" cranesbill: I don't have much hope she's really blue, too many hardy geraniums are falsely called "blue" but I still want to see!