Mirabilis

( mihr - RAB - il - iss )

At-A-Glance Information

This genus is filled with species of flowering perennials (that are sometimes grown as annuals). Most plants in the genus need full sun and little water to perform well. Commonly called Four O'Clock or Umbrellawort, these plants have a mounding habit and produce fragrant trumpet-shaped flowers that open in the late afternoon. In mild climates, they can bloom year-round, with the best flower show in spring and summer. Frost will kill them to the ground, but they will return, sprouting from tubers that overwinter under the soil surface. Plants will self-sow freely. Take care when planting these flowers in your yard, as the seeds and roots are considered toxic to humans and pets.

Mirabilis Species and Varietals

The genus Mirabilis is a member of the plant family Nyctaginaceae and includes around 60 species. The genus name is derived from the Latin word for 'admirable', alluding to the plants' flowers being remarkably colored. Four O'Clock growing zones vary depending on the species. For more information, see the descriptions below. To find your zone, click here: Zone Map.

Mirabilis alipes (Winged Four O'Clock)
This species is native to the southwestern United States and grows in brush, woodland, and dry mountain sloped habitats. It is a perennial herbaceous plant that reaches up to 16 inches tall and 32 inches wide at maturity. Leaves are green and fleshy, and flowers are magenta or cream-colored and bloom in leaf axils in groups of five to nine.

Mirabilis coccinea (Scarlet Four O'Clock)
This species is native to the southwestern United States and northwestern Mexico, They can reach up to two feet tall and produce deep red flowers that open during the nighttime hours. Plants prefer to grow in washes, plains, and on rocky slopes.

Mirabilis expansa (Mauka, Chago)
These plants are cultivated as a root vegetable in the Andes Mountains, and is one of the most important crop species in that area. It is also cultivated in South America. Plants have received a lot of attention for their ability to grow in conditions that don't favor other root vegetable crops.

Mirabilis jalapa (Four O'Clock, Marvel of Peru)
This species grows best in zones 4-24, H1 and H2 as a perennial plant. It is native to Peru, and reaches 3-4 feet tall and just as wide. They bloom in a variety of colors, including white, red, pink, and yellow. The blossoms are fragrant at night, and several different colored blooms may appear on the same plant. Variety 'Jingles' has flowers splashed with different colors.

Mirabilis laevis (Mirabilis califonica) (Wishbone Bush, Desert Wishbone Bush)
This species is native to the southwestern United States and northwestern Mexico. Flowers are typically pink to purplish, and individual plants reach a height of about 2 feet when mature and in bloom. Leaves and flowering stems are green.

Mirabilis longiflora (Sweet Four O'Clock, Long-Flowered Four O'Clock)
This species is native to the southwestern United States and northern areas of Mexico. Flowers open in the late afternoon hours, and bloom through the night. These tender perennials reach 5 feet tall and produce white to pinkish flowers with red-flushed throats on thin stems.

Mirabilis macfarlanei (MacFarlane's Four O'Clock)
This species is native to Idaho and Oregon, and grows in river canyon landscapes. These perennial plants form rounded clumps of foliage and a taproot that can reach down into the soil 8 feet deep. Flowers are pink to magenta in color, and are pollinated by bumblebees.

Mirabilis multiflora (Colorado Four O'Clock, Desert Four O'Clock)
These plants are native to the southwestern United States and northern Mexico, and produce a perennial herb that reaches about 30 inches tall when mature. Flowers are magenta to purple-pink in color, and bloom in leaf axils on upper branches. best in zones 1-3, 7-16 and 18-24.

Mirabilis nyctaginea (Wild Four O'Clock, Heartleaf Four O'Clock, Heart Leaved Umbrella Wort)
This species of Mirabilis is native to the central United States and reaches about three feet tall when mature. Flowers are magenta in color, opening for only a few hours before dropping from the plant. This leaves behind greenish-white papery bracts.

Caring for Mirabilis

Mirabilis seeds can be sown in fall or spring (direct sown into the garden after the last frost of the year or 8 weeks before the last frost date indoors), or plants can be purchased as starts from a reputable nursery. They should be spaced about 2 feet apart in most cases for best coverage, root space and airflow. Mirabilis plants do well in full sun; ideally, these plants should be getting between 6 and 8 hours of direct sun each day to perform and bloom well. In areas with warm temperatures, make sure these plants get some afternoon shade when temperatures are at their warmest (typically between 2 and 4 PM). They can tolerate partial shade, but will let you know if they are not getting enough sun by becoming a bit leggy. They can be trimmed back to encourage a bushier habit to form, but should also be moved to an area with a bit more sunlight if this occurs. Soil should be very well-draining and moderately fertile, with a pH of between 6.0 and 7.5 (slightly acidic to neutral). If local soils are particularly poor in nutrients or do not drain well, make sure to amend the planting area with plenty of organic compost before installing. After planting, apply a thick layer of organic mulch around the area to suppress weed growth, increase soil moisture retention, and maintain consistent soil temperatures.

Water new plantings regularly as they establish a strong root system. At maturity, do not let soil dry out completely; as a general rule of thumb, irrigate whenever the top inch or two of soil feels dry to the touch. 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 Mirabilis plants is simple: remove spent blooms and any unsightly foliage. These plants bounce back well from pruning. Late in the season, plants can 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.

Growing Mirabilis in Containers
Mirabilis can either be grown in containers or in the ground. Ensure that containers have adequate drainage holes, and that they are able to accommodate the plant. Mirabilis plants form tuberous roots, so they will need some space to grow under the soil. As a general rule of thumb, get a container that is at least 16 inches deep for these plants. Ensure that soil is well-draining, and amend with organic material and/or perlite to make it more so if necessary. Plants grown in containers generally need more frequent waterings than those grown in the ground; irrigate container-grown Mirabilis every 8 to 9 days during the fall and winter, and increase to every 2-3 days during the warmer months when plants are actively growing and flowering. Mulch over the top of the soil, ensuring that it stays an inch or two away from stems and foliage to decrease the risk of fungal disease.

Harvesting Mirabilis Tubers
Although these plants are generally considered toxic (the seeds and roots being the most poisonous), some species are cultivated as crops. The species Mirabilis expansa, commonly called Chago or Mauka, is commonly cultivated in Ecuador, Peru, and Bolivia as a root vegetable. After two years' time in the ground, roots can reach the length of a human's forearm. Foliage is also edible. Roots contain irritating substances, and so they must be processed before consumption. Once roots have been left to dry out in the sun, they lose their irritants and become sweeter. Once they are dried, they are then cooked in the same way as Sweet Potato or Cassava. They have a high nutritional value.

Propagation

Mirabilis 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 Four O'Clock, follow the instructions below:

Propagating Mirabilis 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. If you don't have any potting medium on hand, you can make some. Just mix together equal parts (by volume) moss peat and horticultural-grade sand or grit sand. You will also, after a few weeks, need individual 3-inch pots for each seedling that grows.
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 Mirabilis by Division
This type of propagation is relatively simple; you will need a clean shovel, mulch, fresh soil (any kind will do, though it does need to be well-draining), compost and pots (12 inch pots will do, and these are 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 gloved 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.

Mirabilis seeds are ready to be harvested starting in late spring through summer.

Mirabilis seeds are dark brown to black and have rough seed coats.

Problems and Pests

These plants tend to be pest and disease resistant for the most part, but they can be susceptible to developing problems with the following from time to time: