I have two other true blues that I forgot to mention in my first entry: Bog Sage, and Azure Sage.
Bog sage (
Salvia uliginosa) is a tall plant with cobalt blue flowers that begin in late spring and continue until frost. It's a native of South America. In moist soil it spreads like wildlife and sprawls all over everything, but it's easy to pull up when it goes too far. The foliage is strongly aromatic, almost of ammonia -- very strong and even a little hard on the stomach if you're weeding in the middle of it. Deer will not touch it and bees love it. Like Obedient Plant I prefer to put it where it can roam at will.
Azure sage (
Salvia azurea) is new to my garden this year. I grew these from
seed obtained in a trade. They are a lovely very pale shade of blue.
I do have another true blue that grows on the farm, a native gentian called Soapwort (Gentiana saponaria). It has beautiful powder-blue closed flowers that poke up just above ground level and blooms very late, in October and November.
Salvia transylvanica. This salvia is short-lived but seeds in prolifically. A lovely cottage garden salvia. This shade of gentian blue-violet is my favorite color in the garden.
I remember reading about the ageratum effect in a book about perennials, but the color came out very true in this photograph. This is a short form that starts in July and August and blooms until October.
Mexican Petunia (
Ruellia brittoniana). I love the metallic blue highlights on these flowers.
Looking purple in broad daylight
Laurie at Niche Gardens told me that Veronica "Sunny Border Blue" is a spreader.
I certainly hope it is, as I love the color.
We have Blue Lobelia growing wild in all of the ditches here, and like
Cardinal Flower I just let it re-seed where it will.
Blue Mist Shrub (
Caryopteris clandonensis "Dark Knight")
Bluebird Aster is one of the earliest of the
blue asters.

With Lindheimer's Muhly