How To Care For Mariposa Lily Bulbs: Growing Calochortus Lily Plants

Calochortus (Kal-uh-KOR-tus) belongs to the Liliaceae family of plants. It is a lily genus native to North America, British Columbia, Mexico, and the northern part of Guatemala. 

There are seventy species in this genus of herbaceous, perennial, and bulbous plants. Of these seventy species, twenty-eight are native to California. The plants spread freely from the west coast into the western states and can be found in the dry soils of Dakotas, Nebraska, and New Mexico.

Mariposa Lily - Calochortus Lily PlantPin

There is a great deal of variety among the species, and several are cultivated thanks to their very pretty blooms. In fact, the plant’s botanical name, Calochortus, means “beautiful grass” in Greek.

This genus includes richly varied plants, such as:

  • Calochortus Tolmiei
  • Calochortus Elegans
  • Calochortus Pulchellus
  • Calochortus Argillosus
  • Calochortus Venustus
  • Calochortus Raichei
  • Calochortus Persistens
  • Calochortus Catalinae and more…

Because there are so many species, these native plants’ common names vary. They include:

  • Butterfly Tulip
  • Mariposa Lily
  • Globe Tulip
  • Yellow Mariposa (Calochortus superbus)
  • Yellow Star Tulip (Calochortus Monophyllus, Calochortus Amabilis, and Tiburon Mariposa Lily produce yellow-colored flowers)
  • Sego Lily
  • Cat Ear
  • Smokey Mariposa

The genus is divided into four loose subgroups:

  1. Mariposa Tulips bear very large flowers with impressive and intricate coloration and markings. The blooms are bowl-shaped and quite large.
  2. Cat’s Ears (aka Pussy Ears) flowers are quite small. The blooms are very upright and have hairy tepals.
  3. Fairy Lanterns (aka Globe Tulips) are round and ball-like, as the common names suggest.
  4. Star Tulips bear small, star-shaped blooms with erect pointy petals. 

Mariposa Lily Plants Care

Size and Growth

Depending upon the species of Calochortus you have in mind, height can range from 6” inches tall to 3’ feet. Most are fairly slow growers.

Flowering and Fragrance

Calochortus bulbs typically produce one or more flowers on a tall, sturdy stem that arises from the underground bulb in late spring or early summer.

The showy flowers vary in size, structure, and color depending on the species. Petal size may also vary because of soil moisture and years. 

Colors are also many and varied and include:

  • Burgundy
  • Lavender
  • Orange
  • Yellow
  • Purple
  • Bluish
  • White flowers
  • Lilac
  • Gold
  • Pink flowers
  • Red

Unlike other sorts of lilies, these blooms’ petals differ in color and size from the sepals. The insides of petals are usually a bit furry, and the flowers typically bear very distinct spots, streaks, and other markings in the center, along with a conspicuous basal gland.

Calochortus: Desert Lilies That Grow On Limestone

Foliage

The stems of the mariposa lily may be simple or branched. The leaves are typically sparse and narrow. They are not furred.

Light and Temperature

Most Calochortus like full morning sun (6 hours and more daily) and some protection from harsh sunlight in the afternoon. Pussy Ear and Fairy Lantern varieties prefer a consistently shady setting.

These flowering plants are typically winter hardy in USDA hardiness zone 3 and higher. Temperatures lower than 28° degrees Fahrenheit can be damaging. 

In very cold climates, bring the mariposa lily bulbs indoors to overwinter in vermiculite (or paper bags) in a dark, cool, dry place, such as a basement.

Watering and Feeding

As with most native bulbs, a soak-and-dry watering schedule is recommended. Water the mariposa lily thoroughly about once a week. Allow the soil to become fairly dry before watering again.

During the growing season, you can include a weak solution of bulb food when you water. Stop fertilizing after the bloom time of the mariposa lily is complete.

Stop watering when foliage begins to turn yellow. This signals preparation for dormancy. During the plants’ dormant period, do not water at all.

Soil and Transplanting

These native bulbs are a bit picky about their soil. It must be well-drained soil or in light sandy soils. They can also grow well in slightly acidic soil with excellent drainage.

Examples of good soil mixes for Calochortus in containers include:

  • Equal parts high-quality potting mix without manure, fine sand, vermiculite, and perlite.
  • Half sand, a quarter topsoil, and a quarter peat moss and ground dolomite.
  • Equal parts sphagnum peat moss, vermiculite, and perlite.
  • 1 part red lava rock, 3 parts sand, and 4 parts peat moss.
  • Sphagnum peat moss and sand 50/50.

It’s easy to see that the main quality all of these potting mix suggestions have in common is very nearly sharp drainage. Additionally, none of these combinations are very nutrient-rich.

For Calochortus planted in the landscape, rocky soils or slightly heavier soil with significant clay content will work better. 

Lighten the soil with amendments such as leaf mold, fir bark, redwood compost, and the like. A 50/50 mix of native soil and amendments should work well.

Plant Calochortus bulbs three or four inches apart in the landscape. If you are planting seedlings, you can space them more closely at first (e.g., an inch apart) but know that you will eventually need to thin them.

Grooming and Maintenance

In USDA hardiness zone 3 and higher, you can simply overwinter your perennial bulbs in pots or the landscape outdoors. Just be sure the drainage is excellent, or they will not survive the winter.

In colder settings, wait until the plants’ foliage has completely died back. Trim or mow it and then dig the bulbs up.

Allow the bulbs to dry out for a week or so, and then place them loosely into paper bags. Store the bags in a dark, dry location with temperatures consistently between 60° and 70° degrees Fahrenheit.

You can replant the bulbs early in the springtime after the last frost.

How To Propagate Calochortus Lily Plants

The easiest way to propagate Calochortus is by simply planting bulbs. As with most bulbs, choose plump, healthy, undamaged specimens. Plant bulbs early in the spring or autumn in areas that do not have punishingly cold winters.

It is also possible to grow these plants from seeds; however, your plants will not flower for the first three or four seasons.

If you want to try growing Calochortus from seed, start the seed indoors in the late summer or early spring. Simply dust the tiny seeds over the surface of moist, prepared seed starting mix in pots or a seed tray. Then, plant the seeds in late autumn in flats, pots, or outdoor seed beds.

Place the containers in a sheltered setting that stays consistently warm and receives bright, indirect sunlight. 

Keep the seed starting mix slightly moist until you see germination (typically early in springtime). Be aware that excessive watering will cause problems with damping off.

Transition to soak and dry watering and (when the seedlings are large enough) transplant them to their own pots. 

You will need to keep them sheltered for several seasons so that they can develop bulbs. At this point, you can transplant them into the landscape in the springtime.

Calochortus Lily Plants Main Pest or Diseases

With the right care, most Calochortus species are virtually trouble-free. Rodents and gophers may occasionally be a problem. Other pests that might bother these lilies include snails and slugs, and aphids.

As with most plants, excessive watering and/or lack of drainage will cause rot in bulbs planted in pots or a garden or landscape setting.

Overwatered or overcrowded plants may also have problems with botrytis mold. Seedlings may be subject to damping off. If this happens, the use of a fungicide may be helpful.

The majority of the plants in Liliaceae family, including the Butterfly Tulip, Calochortus Tiburonensis, Calochortus Uniflorus, Calochortus Invenustus, and Calochortus Macrocarpus are vulnerable to flies, beetles, aphids, mites, and thrips.

In the wild, some endangered species of Calochortus are threatened by problems such as severe drought and fires, unauthorized collection, being overrun by invasive plants, or being trodden upon.

Is the plant considered toxic or poisonous to people, kids, and pets?

Unlike many members of the Liliaceae family of plants, Calochortus is completely non-toxic to people, kids, pets, and livestock. In fact, it is an edible plant.

Is the plant considered invasive?

This North American native is not listed as invasive in any setting.

Suggested Calochortus Lily Plants Uses 

Many species of Calochortus are cultivated and offered by botanic gardens and specialty nurseries because of their delicate appearance. 

They make wonderful additions to any landscape and are especially well suited for use in:

  • Spring Bulb Gardens
  • Container Planting
  • Pollinator Gardens
  • Wildlife Gardens
  • Perennial Beds
  • Rock Gardens
  • Naturalizing
  • Borders

Traditionally, Mariposa lilies (Calochortus nuttallii, the state flower of Utah) also provided a food source for Native American tribes and Californian tribes. Their bulbs may be eaten raw or boiled. Additionally, the young, fresh flower buds are edible.

NOTE: Native to deserts in the Southwestern United States and northern Mexico, Calochortus kennedyi is known as the desert mariposa lily.

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