Credit: iStock / Maica

Why does pinching the tip of a plant cause it to become bushier?

Pruning changes the flow of the plant’s hormone-like chemicals. In a young geranium, for example, new cells divide rapidly at the tip of the main shoot (apical meristem), which also produces chemicals called auxins that flow downwards. Tucked in safely where each leaf is attached to the stem are lateral buds kept dormant by the auxins. If the apical meristem is pinched, removing the auxins, the lateral buds will spring into growth. From each leaf node emerges a new shoot. Soon a spindly geranium will be bushy and produce many more blooms! With more than 30 years experience in horticulture in B.C.—in wholesale, retail and at VanDusen Botanical Garden for a decade—Carolyn Jones brings a wealth of knowledge and expertise to GardenWise magazine and as staff horticulturist.