Hydrangeas are among the most popular flowering shrubs grown in home landscapes, prized for their showy blossoms in shades of blue, pink, purple, and white. Their lush blooms add incredible visual interest to gardens when in flower. Luckily, with a bit of knowledge, hydrangea enthusiasts can harvest and collect seeds from these plants for future propagation.
Read on to learn the step-by-step process of collecting hydrangea seeds from your own plants. With the right timing and technique, you’ll be able to produce new hydrangea plants from seed in no time!
When to Collect Hydrangea Seeds
The key to collecting viable hydrangea seeds is timing You’ll want to gather seed heads after the flowers have begun fading but before the seeds fully mature and disperse This is generally in late summer or early fall.
Watch for the flowers to take on a papery, dried appearance and begin turning brown. This is a sign that seeds are developing inside the flower head and are nearing maturity. Once the blooms look fully dried and the seed pods appear slightly open, it’s time for seed collection.
Step-by-Step Guide to Harvesting Seeds
Follow these simple steps for collecting hydrangea seeds from spent blossoms:
1. Bag the Fading Flowers
When your hydrangea flowers start to fade and turn brown, carefully slip a small paper bag over the dried blooms before they shed their seeds. You can use a lunch bag or specially designed seed collection bag. Securing the bag around the stem helps capture any seeds that detach early.
2. Snip Off Spent Flowers
Use pruners or scissors to snip off the stem right below the flower head. Pull the bag down tightly around the blossom to cover it completely.
3. Allow Further Drying
Keep the flower head in the bag for another week or two to fully dry out. Store in a dry spot out of direct sun. The bag traps any seeds that loosen during drying.
4. Shake Out Seeds
When ready, gently shake or squeeze the bag to help dislodge the seeds from the dried flower. Carefully open the bag over a bowl or paper plate to catch the seeds as they fall out
5. Separate and Store Seeds
Pour the collected material from the bag onto a sheet of white paper Search for the small, round tan or black seeds, separating them out from any flower debris
Place seeds in an air-tight, labeled envelope or jar. Store in a cool, dry location until ready to plant. Fresh hydrangea seeds can remain viable for up to a year when properly stored.
Tips for Collecting Quality Hydrangea Seeds
Follow these tips to help ensure success when harvesting seeds:
-
Collect from healthy, disease-free plants to promote viability.
-
Choose fully faded flowers – seeds in green heads won’t be mature.
-
Harvest all seed heads on a plant for maximum seed yield.
-
Use paper bags rather than plastic to allow air circulation.
-
Label bags immediately so you don’t lose track of varieties.
-
Dry seeds further if any moisture remains before storage.
-
Discard any seeds that appear moldy or damaged.
How to Grow Hydrangeas from Seed
While hydrangeas can be grown from either seeds or cuttings, seeds offer greater diversity. Each seed carries unique genetic material, so you never know exactly what type of plant it will produce. Here’s a quick overview of how to grow hydrangeas from collected seeds:
Start Seeds Indoors
Sow hydrangea seeds indoors in late winter about 2 months before your last spring frost. Gently press them into sterile seed starting mix without burying too deeply. Maintain warm temperature around 70°F for germination.
Transplant Outdoors
Once seedlings have 2-3 sets of true leaves, transplant into larger containers or nursery beds outside after danger of frost. Harden off first.
Provide Ideal Conditions
Hydrangeas prefer morning sun and afternoon shade. Amend soil with compost to maintain moist, humus-rich conditions. Water regularly for the first two years while plants establish.
Wait for Blooms
Depending on variety, plants grown from seed typically won’t flower until their third or fourth year. Be patient – the surprise blooms will be worth the wait!
Common Questions about Hydrangea Seed Collection
Growing hydrangeas from seeds you’ve collected yourself is rewarding but it can also raise some questions for first-timers. Here are answers to some frequently asked questions:
Where are the seeds located on hydrangeas?
The small, round seeds form inside the dried flower heads. Each large mophead or lacecap flower contains dozens of tiny seed pods.
What do hydrangea seeds look like?
Mature hydrangea seeds are quite small, about 1-3 mm wide. They are round or oval shaped with a pitted surface texture. Seed color ranges from light tan to dark brown or black.
How long are hydrangea seeds viable?
Fresh hydrangea seeds have a viability period of about one year when stored properly in a cool, dry place. For best results, sow seeds within a few months of harvesting. The germination rate decreases over time.
Do I need to stratify hydrangea seeds?
Yes, a cold stratification period prior to planting usually improves germination. Place seeds in moist peat or sand and store for 1-2 months at about 40°F.
How long do hydrangea seeds take to sprout?
Plan on around 2 to 8 weeks for seeds to germinate, sometimes longer. Soaking seeds for 24 hours prior to planting helps speed up sprouting. Keep soil moist and provide bottom heat.
Expand Your Hydrangeas for Free
Part of the fun of growing hydrangeas is discovering new varieties. Collecting and planting seeds from your own plants is an affordable way to increase your collection and enjoy new colors and blooming habits.
With the simple process outlined here, you can easily harvest fresh hydrangea seeds every season. In a few years time, you’ll be rewarded with beautiful new hydrangea plants that cost you nothing more than a bit of effort.
