Hardy Hibiscus Seed Starting Simplified: We’re Answering Your Top Questions.
Do you love the lush look of big, bold, beautiful blooms in your garden? Do you crave a tropical summer oasis—even if you live in a climate with harsh winters? Are you eager to get your hands in the soil as the snow swirls outside? If you answered “yes” to any of these questions, it’s time to grow hardy hibiscus from seed for your garden.
Growing hardy hibiscus species Hibiscus moscheutos, a native to North American wetlands, as well as cultivars of the species H. syriacus, is easy and highly satisfying, as well as a cost-effective way to fill your garden with big, brilliant blooms. In fact, so many gardeners enjoy growing hardy hibiscus from seed that we shared a step-by-step tutorial.
Our original hardy hibiscus growing guide is a great starting point, but we realized many gardeners had questions along the way. To make your seed-starting experience even smoother, we’ve compiled answers to the most frequently asked questions.
Hardy hibiscus is an herbaceous perennial—meaning it dies back to the crown in fall, remaining dormant throughout winter, and then reappears in late spring or early summer.
They can be a little late to the garden party, so don’t fret if your hardy hibiscus takes a bit longer than other perennials to resurface as the growing season begins.
Common Questions
Q: What is the best way to over-winter/store hardy hibiscus seeds so they’ll be ready for planting in the spring?
A: The hardy hibiscus expert from National Garden Bureau member Syngenta recommends keeping the seeds in a cool, dry location. Store them in a refrigerator to keep them cool, but add DampRid® to the seed container (or use the little dry-out packages that come in pill bottles or other consumer goods) to help absorb moisture.
Q: I have hardy hibiscus seeds, but spring planting is 10 months away. Should I wait?
A: While some gardeners plant hardy hibiscus seeds in the ground in fall, most gardeners experience greater success waiting until spring. Store the seeds in a cool, dark place, such as an airtight jar in the refrigerator, until you’re ready to plant. You can start the seeds indoors six to 12 weeks before your last spring frost, or plant directly in the ground after the danger of frost has passed. To help speed germination, soak the seeds overnight in water or lightly nick the hard outer covering to allow the seed to better absorb the water for increased germination success.
Q: Do hardy hibiscus seeds require special handling to germinate?
A: Scarification—the process of carefully removing a bit of the seed’s hard exterior coating by sanding or nicking—does help speed germination. Be careful not to damage the interior of the seed. However, soaking the seed overnight in water to soften its coat also works well to help improve germination.
Q: How do I harvest seed from hardy hibiscus?
A: As the growing season winds down, look for seed pods on your hardy hibiscus—brown pods that should feel dry to the touch. Wait until the pod is fully brown and dry to harvest, as the seeds need to mature. Do not harvest the pod early and green, or the seeds won’t be viable. Collect the seeds once the pod begins to split and open. To save the seeds, store them in a cool, dark place until you are ready to plant in the spring.
Q: If there is a killing frost while the hardy hibiscus pods are still green, will the seed still mature and be good for planting?
A: Unfortunately, hardy hibiscus seeds are not completely mature until the seedpod turns dry and brown, beginning to split. While you can certainly try to harvest and grow the seeds—what’s the harm?—most likely the seeds are not viable, meaning they won’t germinate.
Q: How many seeds should be planted together to make a hardy hibiscus bush?
A: All you need is just one seed for each hardy hibiscus shrub. It’s amazing that a small seed creates such a big, gorgeous, beautifully blooming plant, isn’t it? However, because sometimes not all seeds germinate—or a squirrel or rodent might dig up a seed or seedling—you may want to start a few seeds, then thin them once they reach about four inches tall. Be sure to check the height and spread of each hardy hibiscus variety to determine which one will work best in your area and how much space the plant needs.
Q: Can you recommend good sources for hardy hibiscus seeds?
A: Many of our National Garden Bureau members sell hardy hibiscus seeds.
Some to look for:
- Luna Mix from Harris Seeds
- Luna White from True Leaf Market
- Luna Rose from Outside Pride
- Luna Red from Seeds ‘n’ Such
- Honeymoon Deep Red from Park Seed
- Pink Swirl from Burpee
If you’re collecting seeds from an existing hardy hibiscus shrub, wait until the seed pod is brown and dry to ensure that the seeds are mature.
Do not harvest seeds from a green seed pod, as they have not reached maturity and will not germinate.
Q: I am growing hardy hibiscus from seed. How many plants can I have in a pot?
A: The number of hardy hibiscus plants you can put in one pot depends on two main things:
- Plant Size: How big are the hibiscus plants? Are they seedlings or mature plants?
- Container Size: How large is the pot?
If you’re just starting seeds in the container and plan to transplant them, choose a container large enough to ensure the seedlings receive good airflow and aren’t crowded. However, as the plants grow, they’ll need ample space to develop roots, plus they’ll require plenty of nutrients and water to develop into strong, healthy plants. Make sure to give plants plenty of room to grow until you transplant them into the garden or individual pots.
For fully grown hardy hibiscus, one plant per pot is strongly recommended. Even compact varieties need space to thrive. Therefore, choose a large pot. Remember, the larger the container, the more soil and water retention it will have. Use a pot that is about twice as large as the root ball to give the plant room to grow. Also, keep the container well-watered, because hardy hibiscus appreciate moist soil to thrive.
Think of it this way: baby plants can share a room, but adults need their own space. So when starting seeds, you can have many plants in one container, but they must be transplanted into larger individual containers as they grow and mature. Give your hardy hibiscus plenty of room to grow their roots, and they’ll reward you with beautiful blooms.
Always make sure to select a container with drainage holes to ensure a healthy plant.
Q: I’ve germinated my seeds in paper towels. What type of soil or growing medium should I use when potting them up?
A: For newly germinated seeds, you may want to grow them in a sterile seed-starting mix until they’ve matured a bit. Once they’ve produced two sets of “true” leaves, you can plant them in a light-weight soil, like potting mix, and allow them to grow indoors until after the last spring frost. Ensure that you grow them under lights for 12 to 14 hours a day to produce strong, healthy plants.
When starting hardy hibiscus from seed, remember that the first leaves to emerge are the cotyledon—or “seed leaves.”
Wait to transplant your young plant until you see two sets of “true” leaves.
Q: I started hardy hibiscus from seed. They germinate, reach about two inches—then bend over and die. What’s happening?
A: It’s so frustrating when seed starting doesn’t go as planned. There are many reasons seeds don’t thrive. Make sure you’re using sterile seed starting mix, which helps avoid soil-borne diseases that can decimate young, tender seedlings. “Damping-off” is a common and fatal disease that affects all types of seedlings. The disease is most prevalent when seeds are germinated in cool, wet soils. A heat mat under your seedlings may help regulate soil temperature.
Hardy hibiscus seedlings need 12 to 14 hours of light daily, so inadequate light may also contribute to the seedlings’ demise. Grow lights for indoor seed starting help plants thrive. Also, overwatering is just as bad as underwatering—the soil should be moist, but not soggy. Good airflow is also important for seedling success, so avoid crowding the plants.
Q: I have some young hardy hibiscus plants growing in the ground in zone 6. What do I need to do to keep them alive through winter? Do I need to transplant them to containers and place indoors?
A: Hardy hibiscus are hardy to Zone 4, so your plants should be fine. However, if you’d like to move a few of the plants into containers, make sure to dig deep to get as much of the root as possible, and use potting mix in containers with drainage holes. Place the containers into an unheated garage or storage shed.
If you start hardy hibiscus seed indoors, make sure to harden off tender young plants for about two weeks before planting them in the garden.
Slowly introduce them to outdoor conditions, gradually extending the periods of sunlight and wind, until they’ve acclimated to your garden.
Q: I grew seven of the Luna hardy hibiscus in spring in a pot. Should I plant them in the ground in September in zone 4? Or should I bring them inside for the winter and plant them in the ground next spring as one-year-old plants?
A: Fall is a perfect time to plant perennials like hardy hibiscus. Transplant the young plants to your garden six weeks before the ground freezes. Once frost arrives, perennials begin dormancy, transferring energy into their roots for the following year. Give your freshly planted perennials a period to settle into their new home, which will increase overwintering success.
Q: I planted hardy hibiscus seeds in the ground in a row, right next to their “mother plant”. Now, I have seven, four-inch-tall plants that are way too close together. What is the best way to transplant these babies?
A: Transplant your young plants as soon as possible to give them room to breathe. Young plants compete to receive the nutrients, water, and light they require to thrive. Give them some space so they’re not competing with one another. Also, the plants need time to acclimate to their new location and settle in before winter arrives. Use a shovel to dig up as many of the roots as possible. Try not to disturb the root balls when separating the plants.
Move the plants to their new locations, making sure they’re in full sun for best blooms. Plant the young plants so that the top of the soil ball is level with the top of the new hole. Water in thoroughly to settle the roots. Be sure to water consistently while the roots establish in their new location.
Q: I’ve collected seed from a long-thriving, fuchsia hardy hibiscus growing at a friend’s house, but the plants I grew produced white flowers. How can I ensure that my plants produce the same color flowers as the parent plant?
A: If the plant is a hybrid hardy hibiscus, the seeds you collected may have reverted to one of the parent plants. If you want to ensure that your hardy hibiscus seedlings produce the color you prefer, we suggest purchasing seeds from a reputable hardy hibiscus seed retailer. While it’s fun to collect seed from existing plants, you can ensure you’ll grow a plant that produces the flower color you desire when you purchase seeds from a reputable company.
Q: Which of the H. moscheutos varieties works well in a wetland “swamp” that is consistently wet and highly organic? Do the hybrid varieties tolerate this type of soil?
A: Along with the native species plants, Hibiscus moscheutos hybrids are also perennial wetland plants. Check with your local garden center or extension office to find the varieties that perform well in your area.
Q: How long does it take for hardy hibiscus to bloom if grown from seed?
A: While many perennials do not bloom the first year, the flowering time of hardy hibiscus depends on the variety. Some will bloom the first year, while others take a little longer. Check your seed packet for information about the variety’s bloom time.
Q: My hardy hibiscus in northeast Ohio never gets “woody”. The stems are always green and strong, but not woody. Is something wrong?
A: No worries! Green stems are perfectly fine. “Woody” simply refers to a stem that is strong and holds leaves and flowers without flopping over. Many hardy hibiscus plants become more woody as they age.
Q: Can I collect seeds from the hardy hibiscus plant I purchased from a big box store?
A: Yes! Just wait until the seed pod turns fully brown and dry before you harvest the seeds.
Q: I grew some hibiscus from seeds, and I shared the plants with several people. They didn’t come back up the next year. We live in Michigan. Is there possibly a reason why?
A: The seeds may have been annual, tropical hibiscus instead of perennial hardy hibiscus. Tropical hibiscus is sold in spring at big box stores. Unfortunately, the stores just label them “hibiscus”. However, it’s easy to differentiate a blooming plant: if the flowers are three to five inches across, it’s a tropical hibiscus. If the flowers are larger—like dinner plate-sized–they are hardy hibiscus.
So, do you have all the answers you need to get started? Are you ready to grow hardy hibiscus from seed?
You’ll love the satisfaction of planting a tiny seed, nurturing it, and enjoying the big, bold beautiful blooms of hardy hibiscus for years in your garden.
Do you know that National Garden Bureau members include the most innovative breeders and distributors of hardy hibiscus seeds and plants? If you want to grow beautifully blooming hardy hibiscus, check out the varieties available from National Garden Bureau members.
Learn More by Watching our Ask the Experts About Hibiscus Video!
About National Garden Bureau
Founded more than 100 years ago, the National Garden Bureau educates, inspires, and motivates people to grow home gardens. National Garden Bureau members are horticultural experts, and the information shared with you comes directly from these experts to ensure your gardening success.
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