Most hibiscus bring to mind sandy beaches and tropical getaways. I remember watching iguanas eat hibiscus flowers on a family vacation to the British Virgin Islands when I was young – it was very exciting to watch. While there are no iguanas here, we do have a hibiscus that is native to New York. Out of 40 species of hibiscus, crimson-eyed rose mallow is the only one that is native to New York; able to survive our cold, snowy winters. Crimson-eyed rose mallow is native from Massachusetts and New York to Wisconsin and south and is hardy in zones 4-9. Also known as swamp rose mallow because it likes moist to wet soils, crimson-eyed rose mallow is another common name because of the bright crimson in the middle of a large white flower. There is also a variety (var. palustris) that is pink instead of white.
Rose mallow is an excellent showy species for moist, sunny sites. Large, 6-8 inch blossoms with 5 petals cover the plant and are enjoyed by hummingbirds. While the individual flowers only last one day (yes – only one day!), the plant is so covered with individual blossoms that it blooms for quite a long time. The Rose mallow in the display garden by the pond started blooming around August 20 last summer and bloomed until October 16th.
This summer the rose mallow started blooming on August 19th in the garden. Down south hibiscus are woody shrubs, but this far north our native hibiscus is an herbaceous perennial. This might surprising to hear to someone that has seen one of these plants 7 feet tall in late summer covered in blossoms, but yes, it grows it all in one year, and does it again the next year.
You can deadhead the spent flowers if you don’t like their appearance, but they fall off on their own in a day or two. In very wet conditions, rosemallow will reseed readily. If this is the case and such reseeding is unwanted, just deadhead and cut the stems down for the winter. Otherwise you can let the stems and seed heads stay for winter interest and then cut the dead stems back in the spring to make way for the new growth.
With large woody looking stems that reach 5 to 8 feet tall, this tall plant doesn’t need staking because the stems are so strong. And since rosemallow is an herbaceous perennial, if you want to keep your plants shorter, you can. Cut them back by one half in early June. Flowering will be delayed by 1-2 weeks, but you will get flowers on a shorter plant. Just remember, these plants are late to emerge in the spring. Many people assume their plant must be dead since everything else is already up. But just wait – they will come up – and they are well worth the wait.
Established plants don’t like to be bothered, so just let them be. They get large – so plan ahead – giving them plenty room to grow where you decide to plant. Plant three to four feet apart. They seldom need to be divided. The only downside is that all hibiscus species are loved by Japanese beetles, however ours got some slight leaf damage early on in the summer and then do fine. Japanese beetles tend to me more of an issue earlier in the summer around here, and since our hibiscus blooms so late because we are so far north, it seems to avoid most of the damage from the beetles.
Crimson-eyed rose mallow looks similar to the non-native Rose of Sharon making it a great native alternative. Many people are surprised to learn that Rose of Sharon is actually considered very invasive in much of the mid-Atlantic. Sure, we aren’t in the mid-Atlantic, but based on the current climate change models, we may have the climate of the Mid-Atlantic sooner than any of us can really imagine – so I advise against planting Rose of Sharon in NY as well. We have already seen warmer winters and longer growing seasons, both changes which can allow invasives from warmer climates to begin to invade in our area. Why leave behind an invasion of Rose of Sharon on your property for your kids or grandkids to have to inherit and deal with? Instead, leave them an amazing native landscape for them to enjoy!