I am very fascinated with blue flowers. However, in the tropics blues are not common unlike in the semi-temperate or temperate climates. I don't really know the reasons why this is so. Taxonomists and maybe ecologists and geneticists might have the answers to this, but the physiologists don't. Those blues in Teza's garden are so wonderful, i would love to have them if only it is possible. Also there are blues in Rothchild's Orchid's site. The blue iris lilly, the forget-me-not, and the blue grape hyacinth are also very beautiful.
We at least have the blue Plumbago auriculata. It is said to have originated from South Africa but proliferated also in California and Florida being adapted to subtropical climates. It is very beautiful in hedges or in porch or patio containers; as shown here (cuyamaca.edu), since the plant spills over the sides with lots of pretty blue flowers. Other colors include white, purple, red, or pink, but i haven't seen pink and white in the country. The hedge i posted here doesn't look floriferous because it is very hot this summer that most plants suffer from dieback. At least there are a few umbels although they are small in the photo.
The red Plumbago is Plumbago indica synonymous with Plumbago rosea. It originated from India and now widely distributed in Southeast Asia. Among a lot of herbal and medicinal uses, it is said to be abortifacient. Beware pregnant gardeners! When used in small dosages it has lots of medicinal uses, but in large proportions can be lethal. Both the blue and the red Plumbago are poisonous in higher proportions. They have very diffirent morphological characteristics though. I wonder why they are placed in the same genus.
I linked this also to Todays Flowers: http://flowersfromtoday.blogspot.com/