The actual date at which a particular peony variety begins to bloom depends on the climactic zone you live in. Obviously, peonies grown in Spain or Florida will bloom much earlier in the year than peonies grown in Finland or Minnesota. (For more detailed information on plant hardiness zones, see the Links at the bottom of this page.)
Therefore, all of the terms used (very early, early, midseason, etc.) refer to blooming time with respect to other peonies. Thus, "Early Scout" will probably begin to bloom two to four weeks before "Jan van Leeuwen".
However, these are just guidelines; if you plant a peony bush in a part of the garden which gets lots of hot sunshine (and if it also gets plenty of water), it will bloom much earlier than exactly the same variety planted in an area which is more shaded. Also, the blooming period will last longer in cooler, wetter weather; if the weather is very hot and sunny that year, the blooming period will be intense, but relatively brief.
That being said, peonies typically begin to bloom in late spring or early summer, and an individual bush will bloom for two to four weeks. Peonies do best in hardiness zones 3 to 8; see the Links below to find out what hardiness zone you live in. Here are some examples of peony varieties which begin to bloom at different times during the peony blooming season:
Very Early: Athena, Early Scout, Paeonia officinalis, Paeonia tenuifolia, Roselette.
Early: Buckeye Belle, Charlie's White, Claire de Lune, Coral Charm, Dandy Dan, Edulis Superba, Fairy's Petticoat, Firelight, Flame, Illini Warrior, Lavender, Mahogany, Many Happy Returns, Paeonia veitchii, Paula Fay, Pink Hawaiian Coral, Red Charm, Roy Pehrson's Best Yellow, Shirley Temple, Show Girl, Walter Mains.
Mid-season: Angel Cheeks, Attar of Roses, Auguste Dessert, Baroness Schroeder, Bartzella, Big Ben, Big Ben, Bowl of Beauty, Bowl of Cream, Bu-te, Butter Bowl, Candy Stripe, Cheddar Supreme, Clemenceau, Cora Louise, David Harum, Do Tell, Dr. Alexander Fleming, Duchesse de Nemours, Etched Salmon, Fancy Nancy, Festiva Maxima, First Arrival, Garden Treasure, Gay Paree, Gilbert H. Wild, Henry Bockstoce, Hermione, Hillary, Julia Rose, Kansas, Karl Rosenfield, Kopper Kettle, Krinkled White, La Fée, Lady Alexandra Duff, Laura Dessert, Le Cygne, Lillian Gumm, Longfellow, Madame Jules Dessert, Maestro, Martha Bulloch, Mikado, Miss America, Mister Ed, Mrs. Edward Harding, Mrs. Franklin D. Roosevelt, Paeonia tenuifolia, Paul M. Wild, Pillow Talk, Plainsman, Primevère, Princess Margaret, Raspberry Sundae, Red Red Rose, Ruth Clay, Scarlett O'Hara, Sea Shell, Sorbet, Thérèse, Walter Faxon, Westerner, White Sands, White Wings.
Late: Ann Cousins, Bride's Dream, Chestine Gowdy, Dinner Plate, Elsa Sass, Evening Star, Félix Crousse, Gardenia, Gold Standard, Honey Gold, Le Charme, Mother's Choice, Mrs. Euclid Snow, Myrtle Gentry, Nick Shaylor, Nippon Beauty, Nymphe, Rosa Bonheur, Sarah Bernhardt, Solange, Sword Dance, Tourangelle.
Very Late: Jan van Leeuwen, La France.
To see more detailed information about one of the peony varieties shown above, please click on the underlined name of that peony variety.
Here is a web site which may also help: Peony Bloom Dates; the author puts together a selection of peonies which should provide up to seven weeks of blooms.
Useful Links about Plant Hardiness Zones
This page created and maintained by A. Steinbergs
Last revised September 8, 2008