Pinching is a straightforward and effective pruning method used by gardeners to manage plant growth and encourage a fuller, more compact shape. This technique involves removing the soft, growing tip of a stem, which redirects the plant’s energy from growing taller to growing wider. Applying this method transforms a single stalk into a robust, multi-branched specimen. The goal of pinching is to encourage a higher volume of blooms or produce and create a dense plant structure.
Why Gardeners Pinch Plants
The fundamental reason for pinching is to overcome apical dominance. This biological process is driven by the growth hormone auxin, which is primarily produced in the plant’s apical bud, the topmost growing point of a stem. Auxin travels down the stem and actively suppresses the growth of the lateral buds, the undeveloped shoots located where a leaf meets the stem.
This suppression ensures the main stem grows quickly and maintains dominance, helping the plant compete for sunlight. When a gardener removes the apical bud through pinching, the primary source of auxin is eliminated. This reduction in the hormone’s concentration releases the lateral buds from their dormancy. These side buds activate, causing the plant to develop multiple new shoots beneath the pinch point. The result is a plant that exchanges its single-stemmed, vertical growth habit for a dense, bushier architecture.
Executing the Pinching Technique
Executing a proper pinch requires targeting the right part of the stem to maximize the growth response. The removal must be done just above a leaf node, the point on the stem where a leaf or pair of leaves is attached. The lateral buds that will become the new shoots are located in the axil, the angle between the leaf stem and the main stem. Making the cut just above this point ensures the new growth is stimulated immediately.
For plants with soft, herbaceous growth, such as basil or coleus, the pinch can often be performed using only the thumb and forefinger. This method involves gently snapping off the tender growing tip, usually removing only the top half-inch to one inch of new growth. When dealing with tougher or woodier stems, such as those on mature zinnias or chrysanthemums, clean, sharp snips or pruners should be used to prevent tearing the stem tissue.
The amount of material removed can be categorized as a “soft” or “hard” pinch, depending on the plant’s maturity and desired outcome. A soft pinch removes only the most tender, unexpanded tissue, while a hard pinch may remove the top one to four sets of leaves. A hard pinch tends to awaken fewer side shoots, but those that do grow emerge with greater vigor. Always ensure your cutting tools are sterilized with rubbing alcohol before use to prevent the transmission of plant diseases.
Timing and Suitable Plant Types
The timing of the pinch depends entirely on the type of plant being grown. For annual flowers, the best time to start is when the young plant is six to eight inches tall and has developed at least three to five sets of true leaves. Pinching at this early stage allows the plant time to recover and establish a strong, compact base before it begins to flower.
Many common garden plants benefit from this intervention, including annuals like petunias, cosmos, snapdragons, and zinnias, which produce significantly more blooms when pinched. Herbs such as basil and mint should be pinched repeatedly throughout the growing season, with the harvest acting as a continuous pinch to encourage a constant supply of fresh leaves. For late-season perennials like asters and sedum, pinching in late spring or early summer prevents them from becoming too tall and “floppy” later in the year, and it can also delay flowering for a staggered bloom period.
Avoid pinching plants that naturally produce only a single, dominant flower stalk, as removing the main stem will prevent or significantly delay blooming. Plants that should be left unpinched include larkspur, stock, and single-stem sunflower varieties. For fall-blooming perennials, all pinching should cease around the Fourth of July to ensure the newly stimulated growth has sufficient time to mature and set flower buds before the first frost arrives.