Open the Advanced Search

Hybrid Monkeyflower

Mimulus x robertsii

Please keep in mind that it is illegal to uproot a plant without the landowner's consent and care should be taken at all times not to damage wild plants. Wild plants should never be picked for pleasure and some plants are protected by law.
For more information please download the BSBI Code of Conduct PDF document.


Plant Profile

Flowering Months:
Phrymaceae (Monkeyflower)
Life Cycle:
Maximum Size:
60 centimetres tall
Gardens, marshes, mud, riversides, waterside, wetland.

Yellow, 5 petals
The flowers are solitary and bright yellow, blotched orange or purplish all over. The similar looking Monkeyflower (Mimulus guttatus) is only blotched in the throat (centre).
Seed capsule, 2-valved, up to 1cm long.
The leaves are fleshy and green. They are configured in opposite pairs up the stems and conjoined at their bases.
Frequency (UK):
Occasionally seen  

Similar Species

Other Information


Mimulus x robertsii is a hybrid plant in the genus Mimulus, which is a cross between Mimulus cardinalis and Mimulus guttatus. It is an herbaceous perennial plant that is known for its showy, brightly colored flowers. The flowers can be red, orange, or yellow, and they typically have a dark red or purple spot at the base of the upper petal. The leaves are typically dark green, and lance-shaped.

Mimulus x robertsii is a popular ornamental plant, and it is grown for its bright and colorful flowers. It is a low-maintenance plant that can grow well in moist, well-drained soils and in full sun or light shade. It is also a good plant for attracting butterflies and hummingbirds to gardens. It is not as common as the other species of Mimulus and it's not as easy to find in nurseries or as a wildflower. However, it is a beautiful and hardy plant that makes a great addition to any garden.


Hybrid Monkeyflower, also known as Mimulus x robertsii, is a beautiful flowering plant that is a hybrid between two different species of monkeyflower, Mimulus guttatus and Mimulus luteus. This hybrid plant was first discovered in the early 1900s by a horticulturist named William Roberts, who was fascinated by the unique characteristics of this plant.

Hybrid Monkeyflower is a perennial plant that can grow up to 2 feet tall and 1.5 feet wide. It has bright green leaves that are oval-shaped and slightly toothed. The flowers of this plant are its most striking feature, with shades of yellow, orange, and red, often with spots or blotches of contrasting colors. The flowers are tubular and flared at the end, and they bloom from late spring to early fall.

One of the most interesting things about Hybrid Monkeyflower is that it is a sterile hybrid, meaning that it cannot reproduce on its own. Instead, it must be propagated through cuttings or division. This makes it an ideal plant for gardeners who want a low-maintenance plant that won't take over their garden.

Hybrid Monkeyflower is also highly attractive to pollinators, such as bees and hummingbirds, due to its bright colors and nectar-rich flowers. In fact, it is often used in wildlife gardens and habitats to attract pollinators and other beneficial insects.

In terms of cultivation, Hybrid Monkeyflower prefers moist soil and partial shade, although it can tolerate full sun in cooler climates. It is also a hardy plant that can withstand temperatures down to -10 degrees Fahrenheit. However, it is important to note that this plant is not suitable for regions with hot, humid summers, as it can be prone to powdery mildew.

Hybrid Monkeyflower is not only a beautiful plant but also has medicinal properties. It has been traditionally used by Native Americans to treat a variety of ailments, such as coughs, colds, and skin irritations. The plant contains compounds called flavonoids and alkaloids that have anti-inflammatory and antimicrobial properties.

In recent years, research has shown that Hybrid Monkeyflower extracts have potential as a natural remedy for a range of health issues, including diabetes, cancer, and Alzheimer's disease. However, more studies are needed to fully understand the therapeutic benefits of this plant.

Another interesting aspect of Hybrid Monkeyflower is its role in evolutionary biology. This hybrid plant is an example of how hybridization can lead to the creation of new and unique species. The hybridization of Mimulus guttatus and Mimulus luteus results in a plant with different physical and genetic characteristics than its parent species.

Furthermore, Hybrid Monkeyflower has been studied as a model organism for research on plant hybridization and evolution. Scientists have used this plant to investigate the genetic mechanisms involved in hybridization and the evolution of new species.

In terms of conservation, Hybrid Monkeyflower is considered a rare plant species in the wild. Its habitat is limited to a few locations in California, and it is threatened by habitat loss and hybridization with non-native monkeyflower species. Efforts are underway to protect and conserve this species, including the establishment of protected habitats and the cultivation of Hybrid Monkeyflower in botanical gardens and nurseries.

Hybrid Monkeyflower has also been studied for its ability to adapt to changing environments. As a hybrid, it has the advantage of having a greater genetic diversity than its parent species, which allows it to adapt to a wider range of environmental conditions.

In one study, researchers found that Hybrid Monkeyflower had greater tolerance to drought and salt stress than its parent species. This suggests that hybridization can create plants with improved traits that are better suited to survive in changing environments, which has implications for plant breeding and agriculture.

In addition, Hybrid Monkeyflower is an important plant for ecological restoration projects. Its ability to attract pollinators and thrive in moist habitats make it a valuable addition to wetland restoration and erosion control projects. It can also be used to improve soil quality and prevent soil erosion, as its roots help to hold soil in place.

Finally, Hybrid Monkeyflower is a great plant for gardeners who are looking for a low-maintenance and long-blooming plant. It requires little care once established and can add a splash of color to any garden. Its attractive flowers and ability to attract pollinators make it a popular choice for wildlife gardens and habitats.

In summary, Hybrid Monkeyflower is a versatile and unique plant that has many interesting characteristics. From its ability to adapt to changing environments to its usefulness in ecological restoration projects and its beauty in the garden, this plant is a valuable addition to any landscape.

Distribution Map

Reproduced by kind permission of the BSBI.

Click to open an Interactive Map