growing a swamp rose mallow - Ask Extension
In late June, while traveling back to MD from South, I picked up a light pink swamp rose mallow in NC from the roadside and brought it home with me. I...
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growing a swamp rose mallow #879667
Asked July 31, 2024, 9:44 PM EDT
In late June, while traveling back to MD from South, I picked up a light pink swamp rose mallow in NC from the roadside and brought it home with me. It had few buds as well. I have planted it in a pot. The plant didn't like the change of environment at first and shed all the buds and most leaves. But it survived and now is getting new leaves and now I see few buds as well.
When googled, I found that rose mallows are perennials in MD. How do find out if this one is perennial here or not, as it came from NC? Should I plant this in the ground or leave it in the poi? If I plant in in the ground, would it grow back after the winter? If I should leave it in the pot, do I need to bring the pot indoors during winter?
Howard County Maryland
Expert Response
Plants native to our south aren't always winter-hardy here, even if it's a plant that is also native locally. This is in part because they have adapted to conditions in that region, which in this case includes a longer growing season, so they aren't triggered into going dormant for winter as early as our local plants would be. This is one reason why we encourage gardeners interested in growing native plants to select local ecotypes whenever possible. (An ecotype is a genetically unique portion of a population, like a plant species, that is adapted to living in certain conditions and/or a certain location. They will not always fare well if grown in other parts of that species' native range due to those genetic changes.)
We can't ID the plant pictured to species since it's not flowering yet, as blooms play a key role in confirming plant ID. Maryland is home to two species of native Hibiscus / Rosemallow:
Since it is probably a perennial, winter survival will depend on where it's grown and its genetics (so, the latter aspect will be pot-luck). In a pot, even hardy perennials are more at risk of winter damage or death because the roots are not well-insulated compared to being in the ground. Container soil also dries out faster and needs more careful monitoring for watering needs (even in winter), and plants that prefer to grow in moist habitats do not fare well if the soil gets too dry during winter, even if temperatures remain mild enough. The best chance at surviving the winter will be in an in-ground location in full sun with moist soil. (How wet-tolerant it will be is hard to say until it can be identified to species, but in general, perennial Hibiscus varieties tend to handle wet soil better than dry soil.) Be aware that even locally-native, winter-hardy perennial Hibiscus tend to be late to resume growth in spring, so don't be alarmed if you don't see signs of life until at least early May.
Do not bring cold-hardy plants inside for winter. This risks interfering with their normal dormancy process and may result in poor regrowth, pest issues, or a weakening of the plant while inside (if a plant didn't lose foliage and stay dormant). If a container-grown plant can't be transplanted into the ground but needs to be kept out for the winter, try heeling it in. Heeling-in is simply taking a plant, pot included, and planting it in the ground so it's still surrounded by soil. An alternative that's more involved and less ideal is to build a small raised bed, in effect, around the pot to give it a mound of soil to sit in. (Nurseries use this technique routinely for overwintering unsold stock.) By keeping the pot on the plant, it's easily pulled out in spring so it can be moved back on display or prepared for planting in the ground if a location is then ready for it.
Miri
We can't ID the plant pictured to species since it's not flowering yet, as blooms play a key role in confirming plant ID. Maryland is home to two species of native Hibiscus / Rosemallow:
- Halberd-leaved Rosemallow (Hibiscus laevis), which is rare in the state, a ranking just prior to threatened status
- Crimson-eyed Rosemallow (Hibiscus moscheutos), which is much more locally abundant
Since it is probably a perennial, winter survival will depend on where it's grown and its genetics (so, the latter aspect will be pot-luck). In a pot, even hardy perennials are more at risk of winter damage or death because the roots are not well-insulated compared to being in the ground. Container soil also dries out faster and needs more careful monitoring for watering needs (even in winter), and plants that prefer to grow in moist habitats do not fare well if the soil gets too dry during winter, even if temperatures remain mild enough. The best chance at surviving the winter will be in an in-ground location in full sun with moist soil. (How wet-tolerant it will be is hard to say until it can be identified to species, but in general, perennial Hibiscus varieties tend to handle wet soil better than dry soil.) Be aware that even locally-native, winter-hardy perennial Hibiscus tend to be late to resume growth in spring, so don't be alarmed if you don't see signs of life until at least early May.
Do not bring cold-hardy plants inside for winter. This risks interfering with their normal dormancy process and may result in poor regrowth, pest issues, or a weakening of the plant while inside (if a plant didn't lose foliage and stay dormant). If a container-grown plant can't be transplanted into the ground but needs to be kept out for the winter, try heeling it in. Heeling-in is simply taking a plant, pot included, and planting it in the ground so it's still surrounded by soil. An alternative that's more involved and less ideal is to build a small raised bed, in effect, around the pot to give it a mound of soil to sit in. (Nurseries use this technique routinely for overwintering unsold stock.) By keeping the pot on the plant, it's easily pulled out in spring so it can be moved back on display or prepared for planting in the ground if a location is then ready for it.
Miri
Hello Miri,
Thank you for the information. I am attaching another picture of the plant I have, as the plant is now flowering. The flower has broad overlapping petals which makes it appear disc-shaped. I am not sure if it resembles any of the examples you have mentioned in your email.
I would like to transfer it to the ground rather than keeping it in a pot. I have a location for it. When would be the right time to transfer the plant into the ground. Could I do it now, while it is flowering or should I wait?
Thank you,
Vivi
How beautiful!
That looks like a Swamp Rose Mallow (Hibiscus moscheutos).
There are many, many varieties, but perhaps it is 'Luna Pink Swirl'? If so, it should be perennial for you here. Be aware, though, that they completely die back each winter and can be late to 'wake up' in the spring, so you may want to mark where you plant it.
Here is more about it and where it is best planted/cared for from Missouri Botanical Gardens:
https://www.missouribotanicalgarden.org/PlantFinder/PlantFinderDetails.aspx?taxonid=295322&isprofile=0&chr=48
Christine
That looks like a Swamp Rose Mallow (Hibiscus moscheutos).
There are many, many varieties, but perhaps it is 'Luna Pink Swirl'? If so, it should be perennial for you here. Be aware, though, that they completely die back each winter and can be late to 'wake up' in the spring, so you may want to mark where you plant it.
Here is more about it and where it is best planted/cared for from Missouri Botanical Gardens:
https://www.missouribotanicalgarden.org/PlantFinder/PlantFinderDetails.aspx?taxonid=295322&isprofile=0&chr=48
Christine
