Classification of Sweet Pea Types
The Grandiflora varieties, also now known as the "antique" varieties were developed by Henry Eckford in the late nineteenth century. The standards of these grandilfloras varied from variety to variety. For the most part, they appeared hooded. The flower sizes are smaller than today's modern varieties. The stems length is also shorter, but the fragrance is stronger than most of today's modern varieties. Vines grow to 5-7 feet.
The classic sweet pea descended from the sport of Henry Eckford's Prima Donna which was named Countess Spencer. The Spencers have a wonderful color range, long stems, varying degrees of perfume and are the most highly prized by the exhibitor's of the flower. They usually have four blooms per stem. Vines can grow to 6-10 feet.
The Royal series is a development of the Ferry-Morse Company. They bloom about the same time as Spencers and come in about a dozen distinct colors. Vines grow to 6-8 feet. Galaxy This type blooms about the same time as Spencer varieties and carries up to eight blooms per stem. Vines grow to 6-8 feet.
Early Mulitflora Giganteas
This type flowers far earlier than the Spencers, and blooms are large, with excellent form and placement and strong stems of good length. Vines grow to 6-8 feet.
The Cuthbertson varieties, so named after Frank G. Cuthbertson of the Ferry-Morse Company, who developed them are a result, primarily, of a union between the Spencer varieties and an early flowering type. They will produce between four and six flowers per stem and withstand hot weather better perhaps than the Spencers. Vines grow to 6-8 feet.
Hammett Bi-colors and Shifters
Bred in New Zealand by Dr. Keith Hammett, these striking and unusual bi-colors usually produce four or five blooms per stem. An examples of bi-colors is the Erewhon Sweet Pea. Dr. Keith Hammett also developed color shifting sweet peas. Examples of these are the Blue Shift Sweet Pea and the Blue Vein Sweet Pea. Vines grow to 6-8 feet.
The dwarf sweet peas grow to between 6 and 12 inches and are best suited for patio pots, hanging baskets and border plantings. Their short stems are not suited for cutting.
Semi-Dwarfs or Intermediates
The intermediates grow to heights of 18 inches to four feet and include varieties such as Explorer, Jet-Set series, Knee-Hi and Bijou.
The Lathyrus genus consists of more than 150 species. Some favorites include Lathyrus odoratus (the only one to be scented) and Lathyrus latifolius (the unscented perennial sweet pea). Lathyrus sativus azureus is an outstanding plant which grows to about 4 feet high and can grow in partial shade. It produces gentian blue colored flowers. Lathyrus vernus or spring pea is an herbaceous perennial which produces mauve-purple,blooms in early spring.