By Becky Slater
About the Author
Becky Slater MG 2015-2021. Becky has sold her home and garden in Winnipeg and is moving to Comox, BC and hopes to have a very exciting zone 7 garden with shrubs, trees, vegetables, perennials and her favorite dragon wing begonias in her favorite pots from Winnipeg.
One of my more impressive perennial plants that I have had the pleasure of growing over the years is a Hibiscus mouscheutos, known as hardy hibiscus or swamp rose mallow. It is a species of flowering plants in the family Malvaceae and one I grew especially for the MMGA Garden Tour. I picked up my first hardy hibiscus from a local garden center. It was in a big pot with lots of buds already on the plant. I planted it beside a juniper, in the garden with added compost on top. It managed well in my south facing, partial sun garden. I watered it deeply once a week, more at the beginning. I used slow-release fertilizer on top and regular, dilute feeding every two weeks.
Hibiscus mouscheutos is a marsh plant native to the eastern United States and the southern most parts of southern Ontario, where it is considered a plant of special concern. It has been a popular garden plant in eastern Canada for its zone 4 hardiness and its easy propagation by seed or division of the crown in the fall.
In Winnipeg it is considered hardy, but tricky. This plant benefits from winter protection of mulch or straw. It dies right back to the ground and emergence is very late in spring, even into July. So mark your spot, giving it time to show in the spring, not digging it out by mistake. Patience is a definite virtue waiting for this beautiful plant to come back after our harsh winters. Hibiscus mouscheutos likes organic, well drained, humus rich soil that is not allowed to dry out. The descriptions call for full sun, but it does well with partial to full sun, tolerating heat. Hibiscus mouscheutos has large, 10-12 inch blossoms with five flat overlapping petals that are spectacular in the Winnipeg garden in late summer. The flower is short lived, each bloom lasting 1-2 days. The colors are showy and can be seen from the street in colors of white, pink, red and bicolored with a crimson center. Birds, bees and other nectar lovers enjoy the nectar. Recommended cultivars include Berry Awesome, Cranberry Crush and Perfect Storm in the Summerific series.
It is a vigorous, sturdy, hairy-stemmed and woody-based perennial that grows to 2-6 feet tall and 2-4 feet wide in Manitoba. The leaves can be used dried to make tea and all aspects of this plant are edible, but deer show very little interest in eating it. The bunnies did nibble them in my garden, but not very much, just enough to ruin a stem or two. The pests and problems when listed seem bad. Sawflies, aphids, leaf scorch, leaf blight, rust, and canker can be issues, but I did not have any of these.
My experience is much like Colin Remillard’s at St. Leon’s Gardens (personal communication). Emergence in the spring is very late if hardy hibiscus does over winter. It did come back the second year in my garden, but it was less vigorous and then did not return. Colin thought that over watering might have caused many of the problems gardeners had. He agreed that full to partial sun and well-drained soils were helpful for survival and feeding was necessary for bountiful, beautiful blooms.
You can find seed in some Canadian gardening catalogues. Recommendations include: start seed indoors 14-15 weeks before planting them out. Cover the seed with vermiculite and keep the soil evenly moist. Transplant seedlings once they are large enough to handle without pinching, in full sun. Hibiscus mouscheutos can be planted near a pond. Water and fertilize regularly.
I guess the question for me at the end of this article is, “Would I plant this hardy hibiscus again?” Yes I would, and I would be delighted if it returned the next year, but I think that I would treat it more like an annual that you buy for a showy spot in the garden. Then I would enjoy every single late season bloom until frost.
Photos by Becky Slater unless otherwise
Published: May 2022