The iris flower is a perennial that belongs to the iridaceae family of plants that also includes crocus and gladiolus. The iris flower is one of the most symbolic. It is named after the Greek goddess of love and is considered her sacred flower and the symbol of elegance.
There are about 200 different species of irises. The species are divided into two major groups, rhizome irises and bulbous irises. Rhizome irises grow from a thickened stem that grows horizontally underground, or with part above ground. There are three popular types of rhizome irises: Bearded, Beardless and Crested. Bulbous irises grow from bulbs and typically produce smaller flowers.
Irises can come in a variety of colors--blue and purple, white and yellow, pink and orange, brown and red, and even black. The leaves of the iris flower are long, thin and sword shaped, and grow from the bottom of the plant. The flowers have three petals called standards and three outer petals called the falls.
Improve the soil with a slow release fertilizer and organic matter such as compost, peat moss or rotted manure into the top 4 to 6 inches of soil. Use a spade to make a hole about 10 inches deep and mix in 1 tbsp. of fertilizer with the soil at the bottom of the hole. If the soil is dense, add some gravel or broken pottery into the hole; this will help the water drain out. Fill with the loose soil and put the rhizome or bulb so that it is not covered by more than 1 inch of soil.
Each spring, a thin layer of compost should be spread around the base of the plants leaving any part of the rhizome or bulb that is above the surface exposed. When the flowers fade, cut the stalks all the way back to the base. If it is a variety that will grow more than one flower a year, cut off the faded flowers and water constantly throughout the summer. In the fall, trim away any dead leaves and prune the rest back to just 4 or 5 inches high. When the soil freezes over, cover with a layer of mulch to stop the roots from coming up. If it does happen, just cover them with a layer of soil. This can happen when there is repeated freezing and thawing.
There are irises that can grow in just about any climate, from deserts to swamps. Irises are hardy in most parts of the country from USDA Zone 3 in the north (which is the second coldest zone) to Zone 10 (which is the warmest zone in the continental United States).