Snapdragons (Antirrhinum majus) are vibrant garden plants, often grown as annuals, prized for their tall, colorful flower spikes. Deadheading, the process of removing spent or faded flowers, is an effective maintenance practice for these plants. This action keeps the garden tidy and directly influences the plant’s biological drive to reproduce, allowing gardeners to maximize its display throughout the growing season.
Extending the Bloom: Why Deadheading is Necessary
Deadheading snapdragons encourages the plant to produce a greater number of flowers over a longer period. The biological purpose of a flowering plant is reproduction; once a flower is pollinated and fades, the plant’s energy is redirected toward setting seed. The formation of a seed pod signals that its primary reproductive goal has been met, causing the plant to slow or cease the production of new flower buds.
By removing the spent flower spike before seed pods develop, the gardener “tricks” the snapdragon into believing its reproductive effort has failed. The plant responds by diverting stored energy away from seed maturation and back into vegetative growth. This redirection fuels the development of new side shoots and flower stalks, initiating another attempt at reproduction.
This process results in a significantly extended blooming season, often allowing the snapdragon to continue producing flowers into the cooler temperatures of fall. Subsequent blooms after deadheading may be slightly smaller than the initial flush, but they are numerous and maintain a continuous, colorful display. Regular removal of spent blooms, ideally about once a week, maintains this cycle of energy redirection and continuous flowering.
Step-by-Step: Where to Make the Cut
The correct technique for deadheading snapdragons focuses on encouraging new growth from specific points on the stem. When a flower spike finishes blooming, it will wither and brown, sometimes forming small seed pods at the base of the faded flowers. The goal is to remove the entire spent spike down to a point where a new side shoot can take over.
To make the cut, trace the main flower stem downward from the lowest faded flower or developing seed pod. Follow the stem until you locate the first healthy set of leaves or a visible, developing side bud branching off the main stalk. This point is known as a leaf node and holds the potential for new growth.
The cut should be made cleanly just above this leaf node, using sharp, sterilized gardening snips or scissors. Cutting at this location ensures the plant has a strong point from which to channel energy into new lateral flowering shoots. Cutting back lower encourages a bushier, more compact habit, while cutting higher may result in longer, less vigorous secondary stems.
Beyond Deadheading: Managing End-of-Season Growth
For large plantings where precision deadheading is impractical, or later in the season, “shearing” can be used to manage growth. Shearing involves cutting back the entire plant mass, rather than individual spent stems, to encourage a final round of bloom. This is typically done by removing approximately one-third to one-half of the plant’s overall height, stimulating a flush of new growth and flowers.
Shearing is a time-efficient alternative, especially after the first major flush of blooms fades in mid-summer, allowing plants time to recover and rebloom before the first frost. As the season closes, some gardeners stop deadheading entirely. Allowing the final flowers to remain permits them to set seed, which is necessary for the plant to self-sow for the following year.
If snapdragons are allowed to go to seed, the resulting volunteer plants may not be identical to the parent if the original was a hybrid variety. For those who wish to collect seeds, the pods are allowed to dry and turn brown on the plant, signaling that the seeds inside are mature and ready for collection. This end-of-season decision balances the desire for immediate bloom with the possibility of future, naturally-occurring plants.