Blooms of swamp rose-mallow: My first experience growing successfully Hibiscus moscheutos
Sometimes, the most wonderful things in life come as unexpected gifts. Such was the case when a dear friend surprised me two years ago with a swamp rose-mallow (Hibiscus moscheutos), also called hardy hibiscus. What followed was a delightful journey of rediscovery and wonder, especially considering that I had tried growing Hibiscus moscheutos a few years before, only to mistakenly remove it from the ground in the spring, thinking it was dead.
As I unwrapped the carefully chosen pot, I was greeted by the lush darker leaves of a Hibiscus moscheutos ‘Starry Starry Night’ in full bloom.
A real attention-grabber, Hibiscus ‘Starry Starry Night’ stands out as a compact, intricately branched herbaceous perennial with dark burgundy leaves. Its claim to fame lies in its strikingly oversized pale pink flowers, measuring a generous 7-8 inches across (17-20 cm). These impressive blooms are further enhanced by intricate patterns of darker pink speckles and veins.
But before I delve into the beauty and wonder that ‘Starry Starry Night’ brought to my garden, let me take you back a few years to a lesson I learned about patience and the knowledge one can gain when growing a new plant.
A second chance
You see, a few years prior, I had attempted to cultivate Hibiscus moscheutos in my garden. However, due to my limited knowledge at the time, I had mistakenly believed that the plant had perished during a particularly harsh winter. Regretfully, I removed it from the ground, only to later discover that I had made an unfortunate error in judgment.
In my zone 5 garden, the swamp rose-mallow, exhibits a fascinating growth pattern. One of the most intriguing aspects of these plants is how they send out shoots only at the end of June, ushering in a new phase of their growth.
Nothing happened in 2022
I received the plant in August 2 years ago. It spent its first winter in the bonsai studio, with my semi-hardy hydrangeas, a few degrees over frost, because I did not have time to decide what to do with it and where to plant it. When I took it outside in late May, my husband tried convincing me it was dead. I insisted it was not.
Planting and care
In early spring 2022, I selected a sunny spot in my peony garden, as swamp rose-mallow thrives in full sun to partial shade. The soil in my garden was already well-draining, which is perfect for these plants. After preparing the soil by adding organic matter and compost, I carefully planted my new specimen.
To my surprise, it required minimal maintenance. Regular watering was necessary during the initial establishment period, but once it was established, it showed remarkable drought tolerance.
After its first winter outdoor, and as the summer months rolled in, my Hibiscus moscheutos plants began to flourish as expected. Mid-August brought the promise of buds opening slowly into magnificent blooms. The large, saucer-like blossoms opened one by one, creating a vibrant tapestry of colors. Their resemblance to tropical hibiscus was astonishing, but the fact that they were hardy perennials made them even more special. It produced about 8 flowers and I was ecstatic!
Winter protection
Hibiscus moscheutos is generally considered hardy in USDA plant hardiness zones 5 through 9. While it is known for its resilience and ability to tolerate a range of conditions, including wet soils, it’s important to tailor your care and winter protection based on the specific climate and conditions in your garden. The plant’s cold hardiness can vary slightly depending on the particular variety or cultivar, so it’s a good idea to check the specific requirements and recommendations for the variety you are growing.
Not taking any chance, I provided winter protection, with mulching and covering the plant with a layer of leaves and then a rose cone, because I felt it was essential in my zone to ensure the plant survives the colder months.
A plant with a delayed growth
As spring transitions into early summer, Hibiscus moscheutos begins to prepare very slowly for its vibrant display of large, striking blooms. At the end of June, when the days are longer and warmer, this hardy perennial responds by producing fresh shoots or stems. This growth spurt is a key moment in its annual life cycle.
These new shoots emerge from the base of the plant and often start as small, tender green stems. Over time, they grow taller and more robust, eventually developing into the sturdy, woody stems that support the impressive blooms that characterize this plant.
For gardeners in Zone 5, this growth pattern offers a beautiful and visually dynamic experience. As you watch these new shoots emerge and grow, it’s a clear sign that your Hibiscus moscheutos is gearing up for its show-stopping display of colorful, saucer-sized flowers. This timing is also a helpful indicator for garden care, signaling that it’s an excellent time to provide any necessary maintenance or support to help your hibiscus thrive during its peak blooming season.
The timing of blooming can vary based on geographic location and local climate conditions. In Quebec’s climate, where the growing season may be shorter and cooler compared to some other regions, it’s not uncommon for swamp rose mallow to start blooming later, typically at the end of August. This adaptation ensures that the plant’s stunning, large flowers can flourish when the conditions are most favorable.
This delayed blooming schedule in Quebec adds an element of anticipation and uniqueness to the gardening experience. As summer wanes and the days begin to shorten, the emergence of these late-summer blooms can be a source of joy and color in the garden just when many other flowers are beginning to fade.
The beauty finally unfolds
Then this year, the plant really started to show off. I was pleasantly surprised by the plant’s width during the summer months.
The peak of flowering is now, almost mid-September, at a time when only phloxes, black-eyed Susans, dahlias, a few daylilies and annuals are still competing in beauty.
I cannot count the spectacular number of flowers obtained so far, each darkish pink bud unfolding into a disk-size bright pink flower.
A little botany
Botanically, the flower of Hibiscus moscheutos is a striking and intricate structure composed of various floral parts. Here’s a detailed description of its key botanical features:
Sepals: The flower starts with a protective outer layer of sepals. In the case of Hibiscus moscheutos, these sepals are usually green and form a cup-like structure that encloses and supports the inner parts of the flower.
Petals: The show-stopping feature of the Hibiscus moscheutos flower is its large, colorful petals. These petals are typically broad, oval, and somewhat overlapping. They can come in a range of vibrant colors, including shades of red, pink, white, and even some bicolor varieties. The petals are often slightly ruffled at the edges, adding to their visual appeal.
Stamens: The stamens are the male reproductive organs of the flower. In Hibiscus moscheutos, the stamens are fused or joined together into a single structure called the “column” or “monadelphous column. This fused column surrounds and encloses the female reproductive parts at the center of the flower.
Pistil: The pistil is the female reproductive organ of the flower. It is located at the center of the flower and consists of three main parts: the stigma, style, and ovary. The stigma is the sticky, often lobed structure at the top of the pistil, where pollen grains land during pollination. The style is a slender tube that connects the stigma to the ovary, which houses the developing seeds.
Nectar disc: Surrounding the base of the pistil, there is usually a prominent nectar disc. This nectar disc contains sweet nectar that attracts pollinators, such as bees, butterflies, and hummingbirds, to the flower.
Overall appearance: The Hibiscus moscheutos flower is quite large, often measuring 6 inches (15 cm) or more in diameter. Its showy petals and prominent central pistil and stamens make it an eye-catching and attractive floral display.
One remarkable feature of Hibiscus moscheutos is its daily blooming cycle. The flowers typically open in the morning and remain open throughout the day, closing in the evening. This pattern continues for several days, with new flowers opening each morning. Many new hybrids have flowers that now last longer, even up to three days.
The overall structure and vibrant colors of the Hibiscus moscheutos flower make it a favorite among gardeners and a valuable addition to gardens and landscapes, not just for its beauty but also for its role in attracting pollinators and supporting biodiversity.
Pests and diseases
Hibiscus moscheutos, like many other plants, can be susceptible to certain pests and diseases. It’s important to keep an eye on your plants and take appropriate action to address any issues promptly. Here are some common pests and diseases that can affect your plant:
Pests:
- Japanese Beetles: Japanese beetles are known for their voracious appetite and can cause significant damage to the leaves and flowers of Hibiscus moscheutos. To control Japanese beetles, you can manually remove them from the plants, use traps, or consider insecticides specifically designed to target these pests. Fortunately, as the blooms appear in late summer, Japanese beetles are a bit less numerous and I prefer hand-picking them carefully.
- Earwigs: Earwigs are nocturnal insects that may chew on the leaves of Hibiscus moscheutos. To deter earwigs, you can create traps by placing rolled-up newspapers or cardboard near the plants. Earwigs will seek shelter in these traps during the day, allowing you to remove and dispose of them. The damages of earwigs are mostly ornamental and not detrimental to the plant. My cultivar has dark leaves and this may have been a reason why the earwigs were less voracious.
- Aphids: Aphids are tiny insects that can cluster on the undersides of leaves and feed on plant sap. They can cause distortion of leaves and the secretion of honeydew, which can attract other pests like ants. You can use insecticidal soap or a strong jet of water to wash aphids off the plant.
- Spider mites: These tiny arachnids can cause stippling and discoloration of leaves. You may notice fine webbing on the plant. To control spider mites, you can use insecticidal soap or neem oil and ensure the plant is adequately hydrated, as dry conditions can favor their proliferation.
Diseases:
- Leaf spot: Leaf spot diseases can manifest as dark or discolored spots on the leaves. Fungal pathogens are typically responsible. To prevent leaf spot, avoid overhead watering and provide good air circulation around the plant. Fungicides may be necessary if the disease is severe.
- Powdery mildew: Powdery mildew appears as a white, powdery substance on the leaves, often in dry and humid conditions. It’s another fungal disease. To control powdery mildew, remove affected leaves, improve air circulation, and consider applying fungicides. Despite our very rainy spring, my specimen did not show any sign of fungal diseases, probably because the rest of the summer was hot and dry.
- Rust: Rust diseases create rusty-colored pustules on the undersides of leaves. These can affect the appearance and health of the plant. Remove and dispose of infected leaves to prevent the spread of rust.
Preventative measures such as proper spacing, good hygiene (removing fallen leaves and debris), and maintaining healthy soil can go a long way in preventing both pests and diseases in your Hibiscus moscheutos plants. Regular inspection and early intervention are key to minimizing damage and ensuring your plants thrive. If the infestation or disease becomes severe, consult with a local garden center for more targeted advice and treatment options.
My “real” first experience of growing Hibiscus moscheutos in my peony garden has been nothing short of extraordinary. What began as a surprise present became a cherished addition to my garden, enhancing its beauty and meaning. The burst of color is seen from far away! A friend said it was so beautiful it looked artificial. And another one said it was certainly a tropical plant and not a hardy one!
Indeed, if you’re considering adding a touch of exotic charm to your garden, I highly recommend giving Hibiscus moscheutos a try. Their striking beauty and minimal maintenance requirements make them a fantastic addition to any garden, whether you’re an experienced gardener or just starting to explore the world of ornamental perennials. I’m even thinking of adding one another in the newest peony border.
As I continue to watch my Hibiscus moscheutos thrive alongside my beloved peonies soon going into their winter sleep, I am reminded that every plant has its unique story to tell, and every garden is a canvas waiting to be painted with the vibrant hues of nature’s palette.
