RIPON — Every year at Christmas, a rainbow appears at Park Greenhouse in Ripon.It’s a spectacle with its own shades of colors and not the usual ROYGBIV – red, orange, yellow, green, blue, indigo and violet – that arc over the sky during a celestial convergence of clouds, sun and rain. At the West Ripon Road retail and wholesale nursery, the hues are purple, orange, polka-dotted pink, candy-cane delicate pink, plus pale yellow and pastel blue.The rainbow of colors come from the host of special poinsettias whose untraditional looks stand out like an orange in an apple tree among the sea of red which is your basic and familiar Christmas decorative plant. The painted poinsettias, as the retail nursery staff simply calls them, are all dusted with glitters that look like tiny stars on both leaves and bracts as well as in the plant’s tiny flowers.About a thousand of these painted poinsettias – the paint used is actually a dye, explained Park’s retail store manager Christopher Cover – were shipped and distributed to various stores up and down the state including the Raley’s grocery chain.The bad news is that at the Ripon nursery, these are practically all sold out.