Hydrangeas are popular flowering shrubs, prized for their large, colorful blooms that last through the summer. The direct answer to whether they produce seeds is yes, hydrangeas do have seeds. However, while the biological capacity for sexual reproduction is present, gardeners typically use other, more practical methods for propagation.
The Simple Answer: Yes, Hydrangeas Have Seeds
Hydrangeas, including common varieties like H. macrophylla (bigleaf) and H. paniculata (panicle), produce tiny seeds within their flower heads. These seeds are located in small, dried capsules that form after the fertile flowers have been pollinated. The large, showy petals that people admire are often sterile florets, which attract pollinators to the smaller, inconspicuous fertile flowers.
The seed capsules develop and mature on the plant, becoming ready for collection in late fall or early winter after the flower heads have dried and turned brown. The seeds are remarkably small, often described as the size and color of cracked pepper. Lacecap hydrangeas or the cone-shaped blooms of H. paniculata are typically better sources for viable seeds than the dense mophead varieties.
Seed Collection and Viability
Collecting hydrangea seeds requires waiting for the flower heads to completely dry out on the shrub, typically 8 to 12 weeks after the bloom has faded. Once dried, the entire flower head is clipped and placed in a brown paper bag for several days to ensure any remaining moisture evaporates. Shaking the dried head inside the bag will dislodge the minuscule seeds from their capsules.
Hydrangea seeds often have low viability and exhibit dormancy, making successful germination a slow process. To break dormancy and improve sprouting chances, cold stratification is often required. This involves storing the seeds in a moist medium in a refrigerator for four to six weeks to mimic natural winter conditions.
When sowing, the tiny seeds must be surface-sown on a sterile, well-draining seed-starting mix, as they require light for germination and should not be buried. Maintaining a consistent temperature of 65–75°F and high humidity encourages sprouting, which can take two to eight weeks. Growing hydrangeas from seed is a lengthy undertaking, as seedlings can take several years to produce their first flowers.
Why Gardeners Use Cuttings Instead
The difficulty and slow pace of seed propagation explain why most gardeners and commercial nurseries rely on vegetative propagation using cuttings. The primary benefit of using a cutting is speed; softwood cuttings taken in late spring or early summer can root quickly, often in just a few weeks. This allows for faster production of a mature, flowering plant compared to the multi-year timeline required for growing from seed.
Propagation by cuttings also offers a high success rate and ease, requiring only a small section of a healthy stem and a rooting hormone. Most importantly, cuttings guarantee genetic consistency, producing an exact clone of the parent plant. Seeds collected from hybrid cultivars may not grow “true to type,” meaning the resulting plant could display different flower colors or growth habits than the parent.