The kenilworth ivy is a perennial and small flowering plant that grows on rocks and walls. The little scallops with tiny lilac-blue flowers bloom all summer long. The center of the flowers is yellow to direct or guide the honey bees where the nectar and pollen are.
I. Appearance and Characteristics
Cymbalaria muralis, commonly called ivy-leaved toadflax or Kenilworth ivy, is a low, spreading, viney plant with small purple flowers, native to southern Europe. It belongs to the plantain family (Plantaginaceae), and is introduced to many other temperate locations. Other names include coliseum ivy, Oxford ivy, mother of thousands, and wandering sailor.
Cymbalaria muralis spreads quickly, growing 10–80 cm (3.9–31.5 in) tall. It is a biennial or short lived perennial plant. Its roots are thin and fiberous for reaching into cracks. Its rounded, heart-shaped, or kidney shaped leaves are 5–40 millimeters long, 6–60 millimeters wide, and are supported by nearly all alternating, thin stems, 10–22 millimeters long, and usually purple in color.
The leaves are either smooth (glaberous) or with widely scattered hairs in the subspecies muralis or quite fuzzy (villous) in the subspecies visianii. They may have from three to seven lobes, but most often have five lobes. The leaves are relatively thick and often blushed with purple on their undersides.
Cymbalaria muralis has small flowers that strongly resemble those of a snapdragon. They have sepals at the base of the flower that have lobes 1.5–3 millimeters long and are sharply pointed. The petals form a closed tube 3–5 millimeters long. The lower lip of the flower expanded upwards to block the tube of the flower similarly to the well known snapdragon flowers (palate inflated). The two cushion shaped parts of the lip under the mouth have yellow spots. The lower lobes of the flower are spreading while the upper ones stand up, with rounded ends and 2–3 millimeters long.
The majority of the flower is lilac in color with a yellow throat with darker lines on the upper lobes. Rarely the flowers may be all or nearly all white. At the rear of the flower there is a short spur that is about â…“ the total length of the flower.
Flowering is dependent on local conditions. In Britain it may flower from May until the end of November, while in Eastern Europe it does so from June through July with seeds in September. In North America it may bloom from May to October. In New Zealand it blooms all year long, from January to December.
The flowers are pollinated by bees, but are also self-compatible. Once a flower is fertilized it forms a globular capsule 3–5 millimeters in diameter. Each of the capsules has two openings, each with three valves. The seeds are quite small, just 0.5–1 millimeter with a crescent shape covered in minute warty bumps. This plant has an unusual method for planting its own seeds. The flower stalk is initially positively phototropic and moves towards the light. After fertilisation, it becomes negatively phototropic (“scototropic”) and moves away from the light. This results in seed capsules being pushed into dark crevices of rock walls, where it is more likely to germinate.
The original habitat for Cymbalaria muralis was the narrow niches of rock faces and cliffs. In cooler climates like Lower Silesia in Poland it grows in warm microclimates such as on south or west facing walls of structures or the embankments of rivers. It is considered very characteristic of the vegetation that grows on walls.
In hot climates it becomes a high altitude specialist, for example growing from 1100–1300 meters in elevation in Costa Rica.
II. Subspecies
As of 2024 there are two widely accepted subspecies. The autonym Cymbalaria muralis subsp. muralis and Cymbalaria muralis subsp. visianii. In some sources Cymbalaria muralis subsp. pubescens continues to be listed as a valid subspecies, but it is not listed as valid by most sources.
- Cymbalaria muralis subsp. muralis
This subspecies is hairless or nearly so in most parts. It is widely spread and commonly encountered across much of the temperate world, see distribution for details.
- Cymbalaria muralis subsp. visianii
This subspecies was first described in 1925 as Cymbalaria muralis f. visianii by Sándor Jávorka using an incomplete description by Jenő Béla Kümmerle. In 1972 the Irish botanist D. A. Webb described it with its current name making the distinction from Cymbalaria pilosa, which as of 2024 is regarded as a synonym of Sibthorpia europaea by POWO. All parts of the plants are covered in fine hairs (villous) except for the seed pods, which are hairless.
II. How to Grow and Care
Sunlight
Kenilworth ivy thrives best under partial sun conditions, where the intensity is moderate, avoiding the harsh impacts of midday sun. Light exposure should be dappled or filtered for much of the day to mimic kenilworth ivy’s natural habitat. While resilient, kenilworth ivy can tolerate full sun to full shade scenarios, its growth may be stunted, and foliage could appear less vibrant outside its preferred light spectrum. Outdoors, kenilworth ivy is well-suited to rockeries or wall crevices, where it naturally cascades, benefitting from overhead protection. Despite its versatility, kenilworth ivy’s optimal performance is linked closely to receiving the right balance of light.
Temperature
Kenilworth ivy is a fast-growing perennial flowering plant. Most plant species in the Cymbalaria genus are hardy. Considering their Mediterranean European origin, they are generally cold-resistant and not sensitive to frost. Its germination temperature is about 16 ℃ while the ideal temperature for growth is about 14 ℃. Although they can also withstand various levels of humidity, it’s best to keep it above 50%.
Watering
Kenilworth ivy is a plant that thrives in moist environments, reflecting its native habitat of damp walls and shady nooks. Its water habits lean towards the preference for humidity, requiring regular hydration to maintain its vitality. It needs watering twice a week to ensure optimal growth and health. As an evergreen plant often grown outdoors, kenilworth ivy has a unique ability to absorb moisture from humid air, reducing the need for frequent soil watering during rainy seasons.
Soil
Kenilworth ivy is not particular about the soil type and conditions. It grows in ordinary garden soil as long as it’s fertile and well-draining. This perennial garden plant prefers average to evenly moist soil condition, but will not tolerate waterlogging or soggy conditions as such can result in root rot. The soil pH can be acidic or neutral, but it prefers alkaline soil better. When planting, always use a pot or container with an opening and drainage holes.
Fertilizing
For kenilworth ivy, fertilize with high nitrogen content every 4-6 weeks during active growth in spring and summer. Use a balanced, water-soluble fertilizer diluted to half strength, ensuring to not overfeed, as this can lead to foliage at the expense of flowers. Reduce feeding in fall and withhold in winter. Benefits include vigorous foliage and robust health. Excess can cause root burn or growth issues, so follow guidelines strictly. To apply, water soil before adding fertilizer to avoid root shock.
Pruning
Since kenilworth ivy has a trailing or climbing growth habit, pruning may be necessary as it tends to grow rapidly and excessively.
This plant easily spreads by seeds and grows independently. For that reason, deadheading should be done regularly before it sets new seeds. Deadheading is a practical pruning method that cuts off faded or dead flowers from plants, which not only improves the plant’s overall performance but also controls its potential to get invasive.
Propagation
A versatile and charming perennial, kenilworth ivy adapts well to various environments, thriving in both shaded and sunny locations. Ideal propagation of kenilworth ivy involves sowing fresh seeds directly into well-draining soil. This enables the plant to self-seed effectively and colonize areas with its quaint foliage and flowers. To enhance germination, maintain consistent soil moisture without waterlogging. By ensuring contact between the seeds and soil, kenilworth ivy quickly establishes its sprawling habit, rewarding with a tapestry of green adorned with delicate blossoms.
Transplanting
The optimal time to transfer kenilworth ivy is during the vernal season, as it emerges from dormancy and can root robustly in its new location. Ensure it’s situated in well-drained soil, with partial sun to full shade. Gentle handling is key to protect delicate roots.
Repotting
Repot kenilworth ivy every 2-3 years, ideally during spring to support its vigorous growing season. As a creeping ground cover, kenilworth ivy thrives in a slightly larger pot that encourages its trailing growth. Choose a shallow, wide container with good drainage. Post-repotting, keep the soil consistently moist and provide bright, indirect light to aid kenilworth ivy’s recovery and lush spread.
III. Uses and Benefits
- Garden uses
In gardens ivy-leaved toadflax is planted as a groundcover, particularly on rocky slopes, and planted in wall cracks. Once established it will reproduce on its own, both from seeding and stems rooting themselves. It is winter hardy in USDA zones 5 to 9. According to the garden author Carolyn Singer it is deer resistant.
- Culinary uses
Ivy-leaved toadflax is sometimes used as a salad green in Southern Europe. Its taste is described as like raw garden peas or bitter with a sharp numbing sensation, however it has also been noted as slightly toxic by researchers Marion Cooper and Anthony Johnson.
