Potato plants naturally display blossoms as they progress. They belong to the Solanum genus, the same family as tomatoes, peppers, and eggplants, often called the nightshade family. The appearance of white, pink, lavender, or purple flowers signals the plant has reached maturity. This is a sign of a healthy, growing plant and is not a cause for concern regarding your underground harvest.
The Role of Flowering in Potato Plant Life
Flowering serves the biological function of sexual reproduction, leading to the production of true potato seeds. After pollination, the flowers can develop small, green, tomato-like fruits containing these seeds. This method is used to breed new potato varieties, but commercial potatoes are grown using tubers for consistent cloning.
The intensity of flowering varies significantly between different potato varieties, or cultivars. Some types, like the Russet Burbank, may produce few or no flowers yet still yield an abundant crop. Environmental factors, such as climate and soil conditions, also influence whether a plant flowers heavily or lightly.
Connection Between Flowering and Tuber Formation
The flowering stage often coincides with the critical period of tuber bulking, when underground potatoes rapidly increase in size. Tuber initiation, the start of potato growth, begins much earlier, often four to five weeks after planting, sometimes before the flowers are visible. This initiation is primarily driven by environmental signals, most notably the length of the day (photoperiod) and soil temperature.
The presence of flowers does not mean the plant will neglect its underground crop; tuberization does not depend on flowering. Some gardeners worry that flowering drains energy away from the developing potatoes, but studies show that the plant invests minimal resources in the blooms. Flowering is generally a sign the plant has sufficient resources to support both reproductive growth above ground and tuber growth below ground.
Management of Potato Flowers and Fruits
The practice of removing or “deadheading” potato flowers is often discussed among gardeners, based on the idea that it redirects energy to the tubers. While some older studies have shown a slight yield increase when flowers are removed, most scientific evidence suggests the benefit is marginal and inconsistent. Removing the flowers can sometimes cause a stress response in the plant, diverting energy toward healing the damaged stem instead of increasing tuber size.
For the average home gardener, removing the flowers is largely unnecessary for improving the harvest. A more important consideration is the small green fruits that may develop after the flowers drop. These fruits, often called potato berries, are highly toxic because they contain concentrated levels of solanine, a glycoalkaloid. Solanine is present throughout the potato plant’s foliage and stems, but it is highly concentrated in these berries, which resemble small green tomatoes. If children or pets have access to the garden, it is strongly recommended to remove and safely discard any developing potato berries.