peony flowers come in many different forms
Peony blossoms can change as the plant or flower matures. Japanese forms for example take a few days to take shape. New peony plants can have flowers that seem to be not fully developed and can take up to three years to produce flowers true to form.
Single- five to ten petals with a functional center of stamens and carpels.
Semi-Double- several layers of petals surround a center of stamens.
Japanese- a heavy center of colored sterile stamenodes surrounded by five large guard petals.
Anemone- the center of the flower is nearly filled with stamenodes,a further progression of the Japanese. The satmens are wider forming numerous narrow petals. This center is surrounded by large guard petals. Some catalogs classify these flowers with the Japanese and others with the doubles.
Bomb- have a central raised mass of petaloids surrounded by large guard petals.
Double- large flowers with a mass of petals and no visible stamens.
It is difficult to accurately describe in words a colour, one persons red is another's magenta. So I have tried to be careful and describe the colors a best I can. I have cross referenced many resources and used my own peony blossoms to come up with an accurate description. Environmental conditions can affect the shade and intensity of blossom color. Some fade in strong sunlight and others appear richer in hue during wet or rainy seasons.
Peonies are classified into five major blooming periods. Very early, early, mid-season, late,very late. Depending on your geographical location this can mean they could start in May or, as in my part of Saskatchewan, not until the second week of June. In a year with typical weather patterns, each season of bloom will last about five to ten days, so from the earliest to the latest the bloom period lasts anywhere from 45-60 days.So the gardener can have plants in bloom for as long as many other flowering shrubs.
The vast majority of peonies grow to a height of 30-36 inches (75-90centimeters).I my descriptions I have indicated the ones that grow either significantly smaller or taller than the standard.