How to Get Seeds From Hydrangeas?
The successful process of extracting viable hydrangea seeds involves waiting until fall, identifying ripe flower heads, carefully collecting the seeds, and preparing them for stratification before planting. Hydrangeas primarily propagate through cuttings, so seed-grown plants may not be true to type to the parent plant.
Understanding Hydrangea Seed Production
Hydrangeas, renowned for their vibrant blooms and diverse forms, can be propagated in several ways, including cuttings, layering, and, less commonly, seeds. While propagating from cuttings is the preferred method for maintaining the characteristics of a specific cultivar, growing from seeds opens the door to genetic variation and the potential for creating unique new hydrangeas. However, it’s essential to acknowledge that plants grown from seeds may exhibit traits different from their parent plant – this is known as growing “off-type”.
Benefits of Growing Hydrangeas from Seed
Despite the unpredictable nature of seed-grown hydrangeas, there are several compelling reasons to explore this propagation method:
- Genetic Diversity: Seed propagation promotes genetic diversity within your hydrangea population, potentially leading to increased resilience to diseases or environmental stressors.
- Cost-Effective: Gathering seeds from your existing hydrangeas is a cost-effective way to expand your garden without purchasing new plants.
- Experimentation: Growing from seed allows you to experiment with creating new cultivars and observing the unique traits that emerge.
- A Fun Project: The whole process can be a satisfying and exciting gardening project!
The Hydrangea Seed Harvesting Process
Harvesting viable hydrangea seeds requires patience and careful observation. Here’s a step-by-step guide:
- Timing: Wait until late fall or early winter when the flower heads have dried and turned brown. The seeds will be mature and ready for collection at this point.
- Identification: Not all hydrangeas readily produce viable seeds. Look for flower heads that are beginning to dry out but still retain some structure. The seeds are located in small capsules within the dried flower head. You’ll need to gently tease the flower heads apart to find the seeds. Some cultivars, particularly those with sterile florets, will not produce viable seed.
- Collection: Gently break apart the dried flower heads and collect the small, dark-colored seeds. They can be very small and light, so work in a sheltered area to avoid losing them.
- Cleaning: Remove any remaining flower debris from the seeds. A fine-mesh sieve can be helpful for this process.
- Storage: Store the clean, dry seeds in an airtight container in a cool, dark place (e.g., refrigerator) until you are ready to plant them.
Stratification: Preparing Hydrangea Seeds for Germination
Most hydrangea seeds require a period of cold, moist stratification to break dormancy and promote germination. This process mimics the natural winter conditions that the seeds would experience in the wild.
Here’s how to stratify hydrangea seeds:
- Gather Materials: You will need:
- Hydrangea seeds
- A small container or plastic bag
- Moist (not soaking wet) peat moss, vermiculite, or sand
- Mix Seeds and Stratification Medium: Combine the seeds with the moist stratification medium in the container or bag.
- Refrigerate: Seal the container or bag and place it in the refrigerator for 4-8 weeks. The ideal temperature is between 33°F and 41°F (1°C and 5°C).
- Check Moisture: Periodically check the moisture level of the stratification medium and add water if necessary to keep it consistently moist.
Planting Hydrangea Seeds
After stratification, the seeds are ready to be planted.
- Prepare Seed Starting Mix: Use a well-draining seed starting mix.
- Sow Seeds: Sow the seeds thinly on the surface of the seed starting mix. Do not bury them too deeply, as they need light to germinate.
- Water Gently: Water the seeds gently using a spray bottle or mister.
- Provide Light: Place the seed trays in a bright, well-lit location, but avoid direct sunlight, which can scorch the seedlings.
- Maintain Humidity: Cover the seed trays with a plastic dome or bag to maintain high humidity.
- Germination: Germination can take several weeks or even months, so be patient.
- Transplant Seedlings: Once the seedlings are large enough to handle (typically after they have developed several sets of true leaves), transplant them into individual pots.
Common Mistakes When Growing Hydrangeas from Seed
- Collecting Seeds Too Early: Collecting seeds before they are fully mature will result in low germination rates.
- Neglecting Stratification: Failing to stratify the seeds will significantly reduce their chances of germination.
- Overwatering: Overwatering can lead to fungal diseases and rot.
- Insufficient Light: Seedlings need adequate light to thrive.
- Lack of Patience: Growing hydrangeas from seed takes time and patience.
Comparing Propagation Methods
| Method | True to Type | Speed | Difficulty | Seed Source |
|---|---|---|---|---|
| Cuttings | Yes | Moderate | Moderate | Established plant |
| Layering | Yes | Slow | Easy | Established plant |
| Seeds | No | Very Slow | Moderate | Dried flower heads (may require cross-pollination) |
Understanding Hydrangea macrophylla and Seed Production
While all hydrangeas produce seeds, Hydrangea macrophylla (bigleaf hydrangea), is popular, yet can be challenging to propagate. Many commercially available H. macrophylla cultivars have been bred to produce primarily sterile florets, reducing the number of viable seeds per flower head. If you want to propagate H. macrophylla from seeds, select plants with fertile flower heads, which will have smaller, less showy flowers compared to the larger, sterile ones. These fertile flower heads will produce the best seeds.
Frequently Asked Questions (FAQs)
How long does it take for hydrangea seeds to germinate?
Germination times vary, but generally, hydrangea seeds take anywhere from several weeks to several months to germinate after stratification and planting. Patience is key!
Do all hydrangea varieties produce viable seeds?
No. Many cultivars, particularly those with primarily sterile florets, produce very few or no viable seeds. Look for plants with smaller, less showy flowers, which are more likely to be fertile.
Can I plant hydrangea seeds directly in the ground?
While possible, it’s not recommended. Starting seeds indoors allows for better control over the growing environment, increasing the chances of success.
How much light do hydrangea seedlings need?
Hydrangea seedlings need bright, indirect light. Avoid direct sunlight, which can scorch the delicate leaves.
What is the best soil for growing hydrangeas from seed?
Use a well-draining seed starting mix that is specifically formulated for seedlings. This will help prevent overwatering and fungal diseases.
How often should I water hydrangea seedlings?
Water the seedlings when the soil surface feels dry to the touch. Avoid overwatering, which can lead to root rot.
When should I transplant hydrangea seedlings into larger pots?
Transplant the seedlings when they have developed several sets of true leaves and are large enough to handle without damaging them.
How long does it take for a hydrangea grown from seed to flower?
It can take several years (2-5 years or even longer) for a hydrangea grown from seed to flower.
Can I use seeds from a hydrangea I purchased at a nursery?
Yes, you can. However, remember that the resulting plant may not be true to type and may exhibit different characteristics than the parent plant.
What if my hydrangea seeds don’t germinate?
Several factors can contribute to germination failure, including poor seed quality, insufficient stratification, improper planting depth, and unfavorable environmental conditions. Try again with fresh seeds and carefully follow the instructions.
Are there any specific hydrangea species that are easier to grow from seed?
Some sources suggest that Hydrangea serrata and Hydrangea paniculata may have slightly better seed viability and germination rates than Hydrangea macrophylla.
How can I tell if my hydrangea seeds are viable?
It’s difficult to visually determine seed viability with certainty. One method is to perform a float test. Place the seeds in a glass of water. Seeds that sink are more likely to be viable, while those that float may be empty or non-viable. However, this is not a foolproof method.