The ornamental sweet pea, Lathyrus odoratus, is highly valued for its fragrant, colorful blooms. If your aim is to enjoy a continuous display of these flowers throughout the growing season, the answer is yes, you should remove the developing pods. This action is a fundamental gardening practice designed to manipulate the plant’s natural reproductive cycle. Understanding the reasons behind this practice will help maximize your plant’s performance and ensure safe handling.
The Primary Goal of Pod Removal
The removal of spent flowers and their resulting pods is a horticultural technique known as deadheading. This practice is designed to redirect the plant’s energy reserves away from reproduction and back toward vegetative growth and flower production. By regularly removing the pods, you are essentially tricking the plant into producing more blossoms in an effort to complete its life cycle.
A consistent deadheading routine dramatically extends the sweet pea’s flowering season, often allowing it to bloom for several months. To perform this correctly, pinch or snip off the entire spent flower stalk. Make the cut just above the nearest set of healthy leaves or a new side shoot. Removing the whole stalk prevents the formation of the seed-filled pod.
This proactive maintenance improves the overall appearance of the plant by removing brown, faded material. Regular removal also encourages the development of side shoots, leading to a bushier, more vigorous structure. Deadheading should be performed frequently, ideally every few days, as the pods can form rapidly after the bloom fades.
What Happens If You Leave the Pods On
Allowing sweet pea flowers to remain on the vine and develop into mature pods triggers a profound shift in the plant’s internal priorities. The development of seeds within the pod signifies the successful completion of the plant’s primary goal: reproduction. The plant perceives that its reproductive duty is finished once the seeds begin to ripen.
This biological signal causes the plant to divert its remaining resources almost entirely into the maturation of the developing seeds. This resource allocation comes at the direct expense of flower production, leading to a sharp decline in blooming. The energy is channeled into hardening the pod and nourishing the seeds instead of creating new flower buds.
Once a significant number of pods have begun to mature, the plant initiates a process known as senescence, or biological aging. This hormonal change effectively shuts down the machinery for continuous flowering, bringing the blooming season to an abrupt halt. Neglecting to deadhead even for a short period can quickly stop the flow of new flowers.
Safety and Toxicity Considerations
The sweet pea (Lathyrus odoratus) is toxic, which is a serious consideration for handling its pods. The seeds contained within the pods hold a high concentration of the toxic compound beta-aminopropionitrile (BAPN). This compound is a lathyrogen, and its ingestion can lead to a condition known as osteolathyrism, or odoratism.
BAPN interferes with the proper cross-linking of collagen, a protein fundamental to connective tissues, bone, and blood vessels. Ingestion can result in skeletal deformities, bone pain, and issues with the vascular system. While accidental human poisoning is uncommon, the risk to small children and pets is present due to the appealing appearance of the pods.
It is important to distinguish the ornamental sweet pea (Lathyrus odoratus) from edible peas, which belong to the species Pisum sativum. The pods from the ornamental variety should never be consumed and must be handled with caution when discarding the removed material. Ornamental sweet peas should not be grown near edible varieties to prevent any confusion during harvest.