Some of the delphinium are definitely blue, (like this cobalt blue one which is called 'Aurora Blue') although there can be other shades mixed in with them. The pigment that makes their flowers blue is actually an anthocyanidin and antioxidant called delphinidin. You can learn more about blue flowers, and the science of them, from a wonderful book by Robert Geneve called A Book of Blue Flowers. I bought this book some years back and have kept it in my permanent library.
Kylee, I'm trying to be helpful, here! )
I've mentioned Anchusa before, which like Lithodora, a relative, is one of my love them and leave them plants. If it overwinters, great, but it never has yet for me, and it usually melts down in mid August. But it flowers enthusiastically with deep cobalt blue flowers (they aren't showing up their proper colour here) from May until it wears itself out, so I figure I can just treat it like an annual and enjoy it.
I know that Cynoglossum is a weedy plant in other parts of the world, but here in Nova Scotia, it behaves as an annual, and sometimes selfseeds a little, but never enough to be annoying. Its flowers are about 4 times the size of forgetmenots, and it's still blooming because I have been deadheading it.
I really like blue salvias, even when they are purple instead of truly blue, but this beauty is truly blue. It's Salvia patens, I THINK it's Oceana Blue, but it might be a different cultivar. I bought a couple of them for 2 bucks each at a plant place that I won't mention the name of because this year their plants mostly looked terrible, like they were starving to death. My plants responded to being put in good potting soil and fed SeaBoost, and they are flowering really well. And so blue!
What's singing the blues in your garden?