- Rose Of Sharon Seed Propagation: Harvesting And Growing Rose Of Sharon Seeds
- Harvesting and Growing Rose of Sharon Seeds
- Rose of Sharon Seed Propagation
- Is Rose Of Sharon Invasive – How To Control Rose Of Sharon Plants
- Is Rose of Sharon invasive?
- How to Control Rose of Sharon
- When Rose of Sharon Is Out of Control
- Avoid Unwanted Rose of Sharon Seedlings
- Growing Rose of Sharon or Althea from Seed
- How to Grow Rose of Sharon Bushes From Seed
- Is it Wise to Spread Rose of Sharon Seed in the Wild
Rose Of Sharon Seed Propagation: Harvesting And Growing Rose Of Sharon Seeds
Rose of sharon is a large deciduous flowering shrub in the Mallow family and is hardy in zones 5-10. Because of its large, dense habit and its ability to seed itself, rose of sharon makes an excellent living wall or privacy hedge. When left untended, rose of sharon will drop its seeds close to the parent plant. In spring, these seeds will easily germinate and grow into new plants. Rose of sharon can quickly form colonies this way and are actually considered to be invasive in some areas.
Knowing this, you may wonder, “Can I plant rose of Sharon seeds?” Yes, as long as the plant is not considered invasive where you are or, in the very least, will be grown in an area where it can be appropriately managed. Continue reading to learn how to harvest rose of sharon seeds for propagation.
Harvesting and Growing Rose of Sharon Seeds
In late summer and fall, rose of sharon is covered in large hibiscus-like flowers that are available in many colors – blues, purples, reds, pinks and whites. These will eventually become seed pods for harvesting. Some specialty varieties of rose of Sharon, however, may actually be sterile and produce no seed to propagate. Also, when growing rose of sharon seeds, the plants you get may not be true to the variety you collected. If you have a specialty shrub and you want an exact replica of that variety, propagation by cuttings will be your best option.
Flowers of rose of sharon begin to develop into seed pods in October. These green seed pods then take six to fourteen weeks to mature and ripen. Rose of sharon seeds grow in pods with five lobes, with three to five seeds forming in each lobe. The seed pods will become brown and dry when they are ripe, then each lobe will split open and disperse the seeds.
These seeds do not go far from the parent plant. If left on the plant through winter, rose of sharon seeds will provide food for birds like goldfinches, wrens, cardinals, and tufted titmice. If conditions are right, the remaining seed will drop and become seedlings in the spring.
Collecting rose of sharon seed is not always easy because its seeds ripen in winter. The seeds need this cold period to properly germinate in the spring. Rose of sharon seeds can be collected before they ripen, but they should be allowed to dry out, then placed in a paper bag in the refrigerator until you are ready to plant them.
If rose of sharon seed pods are harvested too early, they may not ripen or produce viable seed. A simple method of rose of sharon seed collection is to put nylon or paper bags over maturing seed pods in late autumn or early winter. When the pods pop open, seeds will be caught in the nylon or bags. You can still leave half for songbirds.
Rose of Sharon Seed Propagation
Learning how to grow rose of sharon seeds is easy. Rose of sharon grows best in humus rich, fertile soil. Sow rose of sharon seeds ¼-½ deep. Cover loosely with appropriate soil.
Plant seed outdoors in autumn or indoors 12 weeks before last frost date for your area.
Rose of sharon seedlings need full sun and deep waterings to develop into tough plants. They may also need protection from birds and animals when they are young.
Is Rose Of Sharon Invasive – How To Control Rose Of Sharon Plants
Rose of Sharon plants (Hibiscus syriacus) are ornamental hedge shrubs that can be prolific and weedy. When you want to learn how to control rose of Sharon, remember that prevention is always easier than cure. Read on for tips on limiting rose of Sharon growth rate and what to do if your rose of Sharon is out of control.
Is Rose of Sharon invasive?
Rose of Sharon, also called althea rose, is native to eastern Asia. The first plants were brought into this country as ornamentals. What is the rose of Sharon growth rate? They typically grow to 10 feet tall and each plant has many branches.
Some plants are very fertile and scatter viable seeds every year. These grow quickly into seedlings in springtime. Unless you act quickly, you will have a
little forest of rose of Sharon plants growing in your garden.
Because of this, the plants are considered rose of Sharon weeds in some states, even escaping cultivation and naturalizing in the wild throughout the southeast. In fact, four states report the species as invasive. As it naturalizes, it crowds out more desirable native plants.
How to Control Rose of Sharon
If you’ve planted rose of Sharon in your backyard, you shouldn’t panic. You can control this shrub quite easily if you are willing to put in the time before new shoots get out of control.
When the rose of Sharon flowers finish blooming, deadheading them takes care of the invasiveness problem. Snip off each faded flower and the developing seed pod under it. That way, you won’t have to worry about seedlings growing.
Another possibility for preventing seedlings in your garden is to buy and plant sterile cultivars like Azurri Satin, Sugar Tip, Lucy, Lavender Chiffon, Diana and Minerva. These won’t have seeds, so you won’t have to deal with seedlings.
When Rose of Sharon Is Out of Control
If you’ve waited too long to use preventative methods like deadheading, you’ll have a harder time if you want to control rose of Sharon weeds. In this case, your best bet is to act in spring.
How to control rose of Sharon seedlings in spring? Use your hoe to dig them out of the ground, roots and all.
Avoid Unwanted Rose of Sharon Seedlings
Rose of Sharon is a mid-summer blooming favorite of gardeners and hummingbirds. But older varieties also add unwanted seedlings to the lawn and garden.
Avoid this problem by growing varieties that produce sterile or no seeds at all. The US National Arboretum introduced Diana, Minerva, Helena and Aphrodite that produce little or no seeds. Other plant breeders are continuing to introduce new sterile or seedless varieties.
Prevent unwanted seedlings on older varieties with a bit of deadheading. Remove the faded flowers and the developing seedpods before they have a chance to form seeds. This is work, but less tedious than digging hundreds of seedlings out of the lawn. If you choose to use a chemical look for one of the weed killers labeled for this use. Spot treat the unwanted seedlings to minimize the impact on the environment. As always, read and follow label directions carefully.
A bit more information: Rose of Sharon flowers come as single or double in white, pink to red or blue to purple. Some have white, rose-pink or red centers. Sugar Tip, Azurri Blue Satin and Blue Angel are a few of the seedless varieties now available.
Growing Rose of Sharon or Althea from Seed
I have many seeds from a beautiful rose of Sharon. I would like to plant them but I’m not sure if I should plant them outside or start them inside in a pot.
The seeds of rose of Sharon (Hibiscus syriacus) require no special treatment to germinate. I would store the seeds in a cool dark location for the winter. Place seeds in a opaque 35mm film canister or an envelope in an airtight jar in the refrigerator. You can plant the seeds directly in the soil after the danger of frost has passed. Or start them indoors like you would flower and vegetable seeds. Harden off transplants before moving outdoors with other transplants. Then grow on in the container or transplant into the garden. In the future you can collect the seeds when the pods brown and split open. Sow the seeds in the desired location or in a vacant garden area until you are ready to move it to its permanent spot in the landscape. Many gardeners find these plants are quite capable of reproducing on their own. Remember that hybrids may not come true from seed. But these surprises are what make gardening fun. And keep in mind it is illegal to propagate patented plants.
How to Grow Rose of Sharon Bushes From Seed
A beautiful and vigorous plant, the rose of Sharon can be started from cuttings, division, or from seeds. If you don’t know how to grow rose of Sharon bushes from seeds, it may take a few tries to maintain moist soil, but starting the seeds is relatively easy. Gather seeds directly from the plant and sow right away or store in a cool, dark place until you are ready to grow your rose of Sharon bushes.
Fill pots with potting soil or a seed starter mix up to 1/2 inch from the rim of the pot. Place one seed in the center of each pot and cover with 1/4 to 1/2 inch of soil or mix.
Sprinkle a little milled sphagnum moss along the surface of the soil. This can help prevent fungi which otherwise thrive on damp soil.
Water the soil enough to make it moist, but not soaking wet or dripping. Allow soil to dry a little before continuing to step 4.
Cover the moist pots with a seed tray cover or slip the pots into individual clear plastic bags. Set the covered pots in a warm location, with sufficient sunlight.
Keep the soil moist until the seedlings emerge, typically in about two weeks. Once the seedlings are out, remove any covering and place them in full sunlight or hang a grow light over your seedlings.
Harden off your seedlings outside once they are 4 to 6 inches tall and your region has passed the last frost of spring. Approximately two weeks of outdoor protection from direct sunlight, wind and weather elements should be sufficient.
Plant hardened seedlings to an area in full sun and well draining soil. Blooms can be seen from your seedlings as early as the next growing season, but they can take three to four years depending on the variety.
I have about a dozen Rose of Sharon bushes and every year at summer’s end I have to clip off the seed pods that result from the lovely flowers that bloomed earlier in the summer. There are thousands and thousands of seed pods which, if left to ripen, would drop and send up thousands and thousands of little tough shoots in the spring. They take root in soil around the bushes and in the grass nearby.
Do the experts have a solution to my problem? It takes a long time to go around clipping off the tips of all those branches but there may be a better way to deal with this issue. — Anne Billington, Cleveland Heights
Anne, you are right. The Rose of Sharon is a beautiful plant but requires an extra bit of care to keep it from spreading into unwanted areas. You are already dealing with this in the most efficient and effective way. By deadheading, you are preventing the problem of the seed spreading and emerging all over your yard next spring.
There are several alternatives, though. First, you can let the seedlings emerge and hand-pull them after a spring rain has softened up the soil. Any that are in your lawn can be easily mowed. I suspect you have already attempted this approach and is how you came to clipping off the seed pods.
Second, use a woody plant herbicide on the seedlings. Be extremely careful not to get it on any of your desired Rose of Sharon shrubs or other woody plants, because it would harm them as well.
Third, try a pre-emergent herbicide. In theory, this would prevent the seedlings from germinating. It is not always successful, since timing is an important part of applying a pre-emergent herbicide. It would also prevent any other seeds from germinating which, depending on what other gardening you are doing, may not be acceptable.
One final option is to replace your Rose of Sharon with a seedless variety. Hibiscus syriacus, the Azurri Satin Rose of Sharon, has a blue-purple flower and is seedless. While this would require the most amount of work up-front, it would solve your problem in the long run.
While none of them is easy, you can decide which option is more favorable for you. Good luck and happy growing.
Garden tasks for July:
- Keep applying deer repellent and make sure to switch up the product. Plants are now lush and blooming so are even more tempting.
- Continue to tie up tomato plants as they grow.
- Keep an eye on water needs; spotty strong storms often produce more runoff than a good soaking.
- Clip those herbs and harvest those veggies.
Christopher Lowe is the superintendent of facility operations at the Cleveland Metroparks Zoo.
Got a question for the Ground Crew? Send it to [email protected], with Ground Crew in the subject line. Or, mail a letter to Ground Crew, Inside and Out, The Plain Dealer, 1801 Superior Ave., Cleveland, Ohio, 44114. Include your name, address and daytime phone number.
Is it Wise to Spread Rose of Sharon Seed in the Wild
Is it Wise to Spread ‘Rose of Sharon’ Seed in the Wild?
Q. I saved seeds from some of my favorite perennials last season. Do you think they would germinate If I were to walk around a lake and drop them here and there? If not, what can I do with them? I’m just trying to make the world a better place!
—Pauline in Reading, Massachusetts
A. This reminds me of my old friends in the ‘Green Guerilla’ gardening group ‘seed bombing’ a vacant lot—except that a lake shore is not a vacant lot! You can do a lot of damage to a wetland by randomly spreading seed around. And my Spider-Sense started tingling independently of the water angle on this one, as I feared that there might be problem plants involved.
Obviously the devil is in the details, so I emailed Pauline to ask what specific “perennials” she’s talking about.
Her response: “I have a mix of sunflowers, phlox, coneflower, black-eyed Susan and rose of Sharon. I know my idea may sound crazy,” she continues, “but I couldn’t stand the thought of just tossing them in the compost!”
Well, at least one of these IS a potential problem: the ‘Rose of Sharon’. It’s not a rose of any kind, but a hardy hibiscus—and I mean ‘hardy’, as in potentially invasive.
How invasive is it?
So invasive it was named “weed of the week” by the USDA Forest Service back in 2006! They describe this Asian native as “a prolific seeder with a deep taproot that is difficult to remove once the plant is two or three years old.” Listed as officially invasive by at least four states—including PA—it has “escaped intended plantings to invade, crowd out and displace more desirable native plants.”
I’ve seen this in my own landscape; one just ‘appeared’ in my front yard several years ago, and is now huge—and I have to keep pulling up the volunteers that show up in other parts of the yard every few seasons.
So why don’t I just cut it down?
It blooms late in the season, when there aren’t a lot of other things in flower. And it attracts pollinators and hummingbirds, who don’t have a lot of other sources of pollen and nectar at that time of the year. I do pull up the volunteers before those famous taproots can become established; and I keep a close eye on the woods. The minute I see that one has gotten into the wild, I’ll cut it and mine down and nail a coffee can over the stumps. But I hope that never happens. Anyway, if aggressive plants like these ‘appear’ next to a lake as opposed to in a kept front yard, there probably wouldn’t be a human caretaker to try and control them. That lakeside could become a forest of hardy hibiscus in twenty years. Even worse, the plants could attract the attention of invasive plant eradicators spraying potent chemical herbicides.
But if you’re starting fresh, you could have your Rose of Sharon without risk; just choose one of the many sterile cultivars that are available. And there are options beyond the Asian Hibiscus syriacus we’ve been discussing. There’s a “Swamp rose mallow” (Hibiscus moscheutos) that’s native to a wide range of North America (USDA Zones 5 to 9) and another ‘swamp’ version that’s native to really wet areas in the American South (Hibiscus coccineus).
But back to the topic. I’m a little surprised that our listener saved seeds without seeming to have had plans for them, but most gardeners would welcome the coneflower seeds she mentions—and the sunflowers (which are annuals; not perennials). Maybe even the Rose of Sharon with a little bit of warning.
Correctly labeled, she could donate the seeds to a public library that has a ‘lending library’ of seeds. Or take them to a local seed swap; the Master Gardener volunteers at her local County Extension office should know where and when such things are happening locally.
And I’m going to go back to something we mentioned in the beginning: rolling the seeds into balls of mud and tossing the resulting ‘seed bombs’ into vacant lots in a big city. Not the ones on her list that have the potential to spread like phlox and Rose of Sharon, but the very pretty non-invasive ones—like the sunflowers, Echinacea and Black-eyed Susan. They would brighten the day of passers-by and make life much better for inner city bees and beneficial insects. But that’s only if they’re sorted out; if she really has a ‘mix’ of seeds in a jar, it’s into the compost pile this season.
But if she carefully harvests and labels this year’s crop she can safely yell “bombs away” at this time next year.