Cherry blossom trees (Prunus genus) are celebrated for their spectacular spring floral displays, but they do produce seeds. Although many people assume these ornamental trees are sterile, the vast majority of cherry blossom varieties develop small fruits that contain the reproductive seed. This article describes the physical characteristics of the seed and the stone that protects it.
The Fruit That Encases the Seed
The seed is contained within a fruit known scientifically as a drupe, which is a fleshy fruit with a hard casing, or stone, surrounding the seed. For ornamental varieties like the Yoshino or Kwanzan cherry, these drupes are typically small and often go unnoticed after the petals fall. Measuring about 8 to 10 millimeters in diameter, they are significantly smaller and less fleshy than commercial cherry fruits.
The fruit begins as a small green orb before ripening to a red or purplish-black color. These tiny fruits are generally bitter and serve the biological purpose of attracting wildlife for seed dispersal.
Physical Identification of the Pit and Seed
The structure often referred to as the “seed” is technically the pit, or stone, which is the hard outer layer (endocarp) containing the true seed. This pit is ovoid, meaning it is slightly broader at one end, and measures about 6 millimeters long by 4 millimeters wide. The exterior surface of this hard casing is typically light brown or tan and may appear slightly ridged or textured.
Inside the protective stone lies the actual seed, sometimes called the kernel. The kernel is soft and has an almond-like or tear-drop shape, mirroring the pit’s contour. This inner kernel is the viable part, containing the embryo and genetic material needed for a new tree to grow. The true seed is a darker brown color than its casing and is delicate, requiring the hard pit for protection until germination.
Propagation Challenges When Using Seeds
Dormancy and Stratification
Attempting to grow a new cherry blossom tree from one of these kernels presents significant biological hurdles, largely due to a natural process called dormancy. The seed’s embryo is programmed to delay germination until conditions are optimal, preventing the seed from sprouting prematurely in the fall. To break this dormancy, the seed must undergo a period of cold stratification, which mimics the natural process of overwintering on the ground. This process requires the seed to be kept in cold, moist conditions, typically between 32 and 40 degrees Fahrenheit, for a duration of 90 to 140 days. Without this extended period of chilling, the seeds will likely remain dormant and fail to sprout when planted.
Genetic Uncertainty
Furthermore, many of the highly prized ornamental cherry trees are complex hybrids or cultivars, and their seeds often do not grow “true to type.” This means the resulting seedling may not resemble the parent tree, producing different flower color, size, or growth habit. For these reasons, commercial growers and nurseries rarely use seeds for propagation, instead relying on methods like grafting or taking cuttings. These vegetative techniques ensure the new tree is a genetic clone of the desired ornamental variety. While the seed provides a means for natural reproduction, the low viability and the unpredictable results make it a challenging path for the average gardener seeking a specific cherry blossom cultivar.