The common garden pea, Pisum sativum, is an annual plant, meaning its entire life cycle occurs within a single growing season. Peas are cultivated for their seeds, which are housed inside a protective pod. This growth habit is fundamentally different from that of a woody, perennial tree, which lives for many years and develops a sturdy trunk.
The True Growth Habit of Garden Peas
The garden pea plant grows as an herbaceous vine with soft, green stems, lacking a woody structure. Peas are considered a cool-season crop, thriving in spring or fall temperatures between 55°F and 75°F. The plant relies on specialized appendages called tendrils for support.
These tendrils are slender, curling modifications of the leaves that wrap around nearby supports like a trellis, netting, or stake. Securing themselves allows the pea vines to grow upright, maximizing sunlight exposure. Without this vertical support, the weak stems would sprawl across the ground. The plant’s short life cycle, typically maturing in 60 to 70 days, contrasts sharply with the slow, multi-year growth of trees.
Botanical Classification: Peas as Legumes
Peas belong to the large plant family Fabaceae, commonly known as the legume family, alongside plants like beans, lentils, and peanuts. A defining characteristic of a legume is the fruit structure: a pod that develops from a single flower ovary. This pod typically splits open along two seams when mature to release the seeds, distinguishing legumes from the fruits of trees.
Legumes are unique because they form a symbiotic relationship with specific soil bacteria called Rhizobia. These bacteria live in nodules on the pea plant’s roots and perform nitrogen fixation. This process converts atmospheric nitrogen gas into ammonia, a form the plant can use. This ability to enrich the soil is inherent to the legume family and differs significantly from the nutrient acquisition methods of most tree species.
Cultivation Differences Among Common Pea Types
The common pea (Pisum sativum) is divided into several types based on how they are consumed, and these variations have distinct growth habits that influence cultivation.
Types of Peas
Shelling peas (English peas) are grown for the plump seeds inside the pod, which is discarded because it is fibrous. Snap peas, a cross between shelling and snow peas, have thick, edible pods containing full, sweet seeds. Snow peas have flat, edible pods harvested before the seeds have fully developed.
Varieties within these categories are classified by height and need for support, generally falling into climbing or bush types. Climbing or pole varieties can reach heights of five to six feet and require substantial trellising to grow vertically. Bush varieties are more compact, often growing only two to three feet tall. While they may support themselves without external structures, they still benefit from support to keep the vines off the ground.