From my perspective, I am a tender perennial, often grown as an annual, with a natural instinct to trail and spread. My energy is initially focused on a primary growing tip, a single leader that races forward. While this creates long, beautiful vines, it can sometimes come at the expense of density. Without intervention, I may direct most of my resources to this main stem, resulting in a plant that is leggy with fewer lateral branches. These lateral branches are where the majority of my prolific, petunia-like flowers bloom. Therefore, the act of pinching is a signal to me to change my growth strategy from vertical exploration to horizontal bushing.
When you pinch me, you are physically removing the terminal bud, the tiny set of new leaves at the very end of a stem. This bud produces a hormone called auxin, which suppresses the growth of the lateral buds further down the stem. It's a form of apical dominance, ensuring the main stem remains the priority. By pinching off this tip, you remove the primary source of that suppressing hormone. This signals to the dormant buds in the leaf axils (the points where leaves meet the stem) that it is now safe and advantageous to awaken and grow. Each of these awakened buds will develop into a new stem, which will, in turn, produce its own set of leaves and flower buds.
The method of pinching is crucial for my health and response. Please use clean, sharp fingernails, scissors, or pruning snips to make a precise cut. Do not tear or crush my tender stems, as this can invite disease. Your target is to remove the very tip of the stem, just above a set of healthy leaves or a leaf node. Ideally, you should pinch back about one-half to one inch of the stem. This small but strategic removal is enough to break the apical dominance without causing me undue stress. The goal is to encourage two new branches to emerge from that single point, effectively doubling the flowering potential on that stem segment.
You should begin pinching me early in my life cycle, as soon as I have developed about three to four sets of true leaves and am well-established in my container or basket. This initial pinching sets the foundational, bushy structure for the entire season. Do not be shy; a good early pinch is an investment in my future fullness. After the initial pinching, continue to monitor my growth. As the new lateral stems grow and develop another three to four sets of leaves, you can pinch their tips as well. This process of successive pinching can be repeated every few weeks until I have achieved the desired density. Please cease pinching about 6-8 weeks before you expect the first fall frost, as I will need time for these final new stems to mature and produce their magnificent flush of flowers.
