A quick entry for the day about Allium cristophii, or the star of Persia. This photo was uploaded to the Botany Photo of the Day Flickr Pool back in May of this year by Christopher (aka c.young@Flickr). Thanks for sharing, Christopher!
Allium cristophii (subgenus Melanocrommyum), of the Amaryllidaceae, is a bulbous perennial native to Iran, Turkey, and central Asia. It is planted ornamentally for its large, spherical, purple flower heads of over 100 individual flowers that bloom in the spring. The flower heads of this species are noted to be amongst the largest produced by ornamental onions at 20-25cm in diameter.
The star of Persia is mentioned to be easily grown. Planting in rich, sandy to gritty soil in well-drained loams in full sun should do the trick. Apparently they do well in dry, sunny areas, particularly as over-moist soils may cause bulb rot. This species may colonize over time. If you want to control unwanted spread, deadhead the flowers before seed set.
Today I did want to write about Helianthus annuus, as this species was mentioned in the news yesterday. However, it has been featured on Botany Photo of the Day both last year and in 2007. To quickly summarize, it was highlighted in the news from Nature that this flower species bends to track the path of the sun, and researchers have found it is not only a response to light, but also to an internal clock. To see more, check out the article and accompanying video.