I grow more iris than I used to because deer leave them alone, and I’ve discovered that there are many things I did not know about these flowers.
There are tiny iris that bloom very early, e.g. Iris reticulata, as well as many kinds that come later.
By growing many different kinds of iris, one can have iris in bloom over a long period. The dwarfs as well as the small-flowered Siberian iris bloom earlier in the spring than the bearded German iris. Re-blooming bearded iris are also now available.
A “beard” is a line of fuzzy hairs on top of the bottom flower petal, which is called a “fall.” Each German iris has three falls or lower petals. The upper petals of a German iris are referred to as “standards.”
Most types of iris prefer about six hours of sun a day.
Japanese iris and Louisiana iris have a characteristic flower form that is different from the German iris, and they like more moisture than the German iris.
Spuria iris have the tallest plants and are the only types that do not need to be divided.
If you have German iris in your garden that are not blooming, they may have been planted too deeply. The top half of the rhizomes should be visible above the soil. They also could need to be divided or may have iris borer caterpillars attacking them. All irises need fertilizer to bloom well, but do not overdo it with manure or fertilizer that is high in nitrogen.
Some iris petals are ruffled, bicolor, crinkled or pleated, but all types of iris are good garden residents if you try to meet their fairly minimal requirements.