A few years ago I picked up a small Delphinium plant, and I was pleasantly surprised at how well this plant adapted to my garden. In my region the Delphinium plant produces multiple rounds of blue-violet blossoms, and last year we had three separate flowering periods with these plants.
The brilliant blue and violet hues the plant produces contrast well with many other colors. As you can see in the image, the bluish colors mesh well with the yellow irises, and the constancy of the blue Delphinium makes for unexpected color bonanzas when later blossoms arrive. From another angle they also pair well with some red and pink poppies that are hidden in this image.
The various species of Delphinium are rather toxic, though, so be sure to keep Delphinium away from small children and pets. The plant produces the toxic alkaloid delphinine, which can be fatal in large doses.
This perennial plant can be propagated from seed, or you can also split the rhizomes and start new colonies in other gardens. In this garden the Delphinium grew from a single stalk to about eight stalks in three years: moderate growth, but not the type of plant that overwhelms a garden.