Mimulus

( MIM - yew - lus )

At-A-Glance Information

This genus, commonly called Monkeyflower, is native to eastern North America, Asia, Australia, Africa, and Madagascar. Species in this genus can be grown moist or wet soils or in arid environments. Flowers can be white, yellow, orange, pink, purple, or blue and bloom in spring and summertime. Several species are cultivated as garden ornamentals, and are useful in mixed beds, wildflower gardens, informal landscapes, and cottage-style gardens. Some species can also perform very well in bioswales and rain gardens, able to handle periods of saturated soil with ease.

Mimulus Species and Varietals

The genus Mimulus includes 7 species and is a member of the plant family Phrymaceae. It is closely related to Erythranthe and Diplacus. The genus name is derived from the Latin word mimus (meaning 'mimic'), referring to the flowers mimicking the faces of monkeys. The best growing zones for Monkey Flower vary depending on the species. For more information, see the descriptions below. To find your zone, click here: Zone Map.

Mimulus alatus (Sharpwing Monkey Flower, Winged Monkey Flower)
These plants produce scentless flowers and are native to North America, producing blue to violet flowers from June through September. These plants grow rapidly, but have a shorter life span than other Monkey Flowers. Individual plants reach up to 1-3 feet tall and thrive in persistently wet conditions. This species grows well in USDA hardiness zones 5a-8b.

Mimulus gracilis (Slender Monkey Flower)
These Monkey Flowers produce purple blooms along upright stems that reach about 14 inches tall. They are commonly seen in depressed areas after instances of flooding, and are native to Australia. Slender Monkey Flower grows well in USDA hardiness zones 9-11 and prefers damp or wet environments.

Mimula ringens (Allegheny Monkeyflower, Square-Stemmed Monkeyflower)
These flowers are native to central North America, though they have spread into the Pacific Northwest, where they are thriving. Plants reach up to three and a half feet tall and have square stems with green leaves. Flowers are light purple to violet in color, and bloom in spring and summertime. This species is best in moist areas, and grows well in USDA hardiness zones 3-9.

Caring for Mimulus

Plant Monkey Flower in a space in the garden that receives full sun; ideally, these plants grow best when they get between 6 and 8 hours of sun each day. Some species can do well in partial shade, and it is always a good idea to provide some shelter from the sun's rays when temperatures are at their warmest (in the afternoon). They enjoy a substrate that is well-draining with a pH of between 5.0 and 8.0 (acidic to slightly alkaline). Soil requirements vary somewhat by species, some requiring fast draining soils and others that enjoy boggy conditions. Make sure to read the growing requirements for the species you are cultivating before planting. After installing, apply a thick layer of mulch around the planting area to suppress weed growth, maintain consistent soil temperatures, and increase soil moisture retention. Water new plantings regularly as they establish a strong root system. At maturity, they appreciate regular waterings, and do not like when soil dries out completely.

Fertilize yearly in early springtime with an application of 2 inches of compost around the base of plants. Pull mulch back before applying, work the compost gently into the soil a bit, water it in, and then replace mulch. These plants are not heavy feeders, and this should be sufficient to provide the necessary nutrients for the active growing and flowering seasons. Pruning Monkeyflower plants is simple: remove spent blooms and any unsightly foliage. These plants bounce back well from pruning. Late in the season, plants have a tendency to get leggy, especially if they are grown in too much shade. Plants can be cut down to about four inches tall at this point, and a flush of new growth and flowering will be triggered. Monkeyflower plants can be divided if they are looking a bit unhealthy or crowded. For information on how to successfully divided Mimulus, see the Propagation section below. There are annual and perennial species of Mimulus. Perennial plants can survive in the landscape for 3 to 5 years before needing to be replaced, and annuals are typically pulled and composted at the end of the growing season, replaced with new plants in the next year.

Propagation

Mimulus can be propagated either by division or from seed. To ensure that your propagated plant will have the exact same qualities and characteristics as the parent plant, use the division method. If you would like to experiment and see what plant you can grow from seed, just keep in mind that it will not necessarily be the same as the parent plant. To propagate your Monkey Flower, follow the instructions below:

Propagating Mimulus by Seed

Keep in mind that the plant you get from seed will not necessarily mimic all of the characteristics of the parent plant. To propagate by seed, you will need a paper bag, a pot or tray filled with well-draining compost or other organic material, a spray bottle and a fork. The best potting medium for seed germination is a light blend of 1/3 pasteurized soil or compost, 1/3 sand, vermiculite or perlite, and 1/3 coconut coir or peat moss.
Harvest your seeds. The seed heads on plants are pretty easy to spot, they're left behind after flowers have faded. Once they have dried out and begun to split open, you can harvest the seeds inside. Cut them off of the plant, placing them in a paper bag. Harvest as many as you can, and place the paper bag in a dry, cool, dark area. They will continue to split open and release the seeds contained inside. Once they have been released, take them out of the bag and put them in a container so you can work with them.
In either late winter or early springtime, get your container prepared. Water your prepared seed tray or pot filled with soil, and ensure that good drainage is occurring. Place your seeds in your prepared pot or seed tray about a quarter inch to a half-inch under the soil surface. Cover them with soil and water with your spray bottle. Place your tray of seeds in a warm area that receives bright, indirect light. A greenhouse is the most ideal climate, but a planting tray inside a window will do as well. Germination usually takes 2-6 weeks from sowing. Once you begin to see seedlings sprout and they are able to be handled, transplant them to their own individual 3-inch pots, filled with the same potting medium as described in Step 1. Loosen the seedlings from the potting medium by digging down with the tines of your fork about an inch and a half, gently working the seedling up until it is out. Then, replant the seedling in its individual pot.
Keep the seedling's potting medium moist, but not wet, by spraying the soil with your spray bottle. Keep your new plant in an area with bright light (though not direct sunlight) and temperatures between 65 and 72 degrees Fahrenheit. Ensure that the soil stays moist, but not wet, until the next spring (after the danger of frost has passed), when you can transplant it to its new home.

Propagating Mimulus by Division
This type of propagation is relatively simple; you will need a clean shovel, mulch, fresh soil, compost and pots (only necessary if you will be saving divided plants for transporting elsewhere). Division is best done in very early spring (after the plant has entered dormancy, but before it has begun its new spring growth), and needs to be done every few years regardless of whether you have the goal of propagating the plants for best performance. To propagate by division, follow these steps:

Using a shovel, dig up your existing plant. Start from the outside and work your way in to avoid damaging the root(s). Once you have worked it up out of the ground, lay it out.
Start to tease apart the roots with your fingers. Once the roots are untangled, separate your plant into segments, ensuring that each one has at least one thick root section attached.
Prepare your pot(s) or new planting site(s) with amended, well-draining soil. You can either bring in new soil or simply amend your existing soil with compost to complete this task. Then, plant your divisions and water thoroughly.
Apply a thick layer of mulch over the new planting to protect it from cold weather as it acclimates to its new home. Then, enjoy watching it sprout in the next growing season.

Mimulus seed pods contain many very small seeds.

Mimulus seeds are quite tiny.

Problems and Pests

Mimulus have no serious pest or disease issues in the landscape. For information on commonly-encountered pests and diseases in home gardens, including how to treat and prevent them, consult the following pages:

Pests & Pest Management

Plant Issues