Crocus

( KROH - kus )

At-A-Glance Information

These low-growing perennials are native to the Mediterranean region and the Caucasus and grow from corms. They require full sun during blooming periods and light shade otherwise if the climate is warm. They appreciate regular waterings during their growth and blooming periods. Leaves are grass-like and flower color and shape varies widely. Most species bloom in winter or early springtime, though some will bloom into fall. They look best when massed together in the landscape. These plants are great for rock gardens, between stepping stones, and in container plantings. This genus contains the species that is used in the cultivation of the spice Saffron. Take care when planting Crocus flowers in your garden, as most species are poisonous to humans and pets.

Crocus Species and Varietals

The genus Crocus includes around 100 species, and is a member of the plant family Iridaceae. Crocus grows best in USDA hardiness zones 3-9 or Sunset growing zones 1-24, and will perform best in cold-winter areas. For more growing information, see the descriptions below. To find your zone, click here: Zone Map.

Crocus alatavicus (Saffrom Crocus, Crocus)
This interestingly colored species of Crocus is native to the Middle East and Asia, and reaches 3-4 inches tall at maturity. Petals have black-purple stippling on the undersides, visible before flowers open to reveal yellow-orange stigmas and white petal surfaces. Flowers will bloom between February and May.

Crocus ancyrensis (Ankara Crocus, Snow Crocus)
This species produces small yellow flowers in early to late wintertime, and is native to Northern and Central Turkey. It was first discovered around Turkey's capitol city, Angora (hence the common name Ankara Crocus). Each corm will produce 2-3 flowers per growing season. This species reaches 3-6 inches tall when mature and in bloom.

Crocus angustifolius (Crocus susianus) (Cloth of Gold Crocus)
This species produces orange-gold flowers with brown stripes shaped like stars. They bloom in early winter and are native to Ukraine and Armenia. Leaves are narrow and grass-like, emerging in springtime. Flower petals commonly have maroon striping or markings on the undersides, most visible before the flowers open up. Plants in this species reach up to 2-6 inches tall and wide at maturity.

Crocus banaticus (Iris-Flowered Crocus, Byzantine Crocus, Banat Crocus)
Native to Romania, Serbia, and Ukraine, this species reaches 4 inches tall at maturity when flowering, and produces violet flowers (though blooms are sometimes white) in fall. Petals are not striped, as in many other species in the genus. Individual plants reach up to 4-6 inches tall.

Crocus baytopiorum (Baytop's Crocus, Baytop's Saffron, Autumn Crocus)
This species, discovered in 1973 by professors from Istanbul, is a perennial plant native to Turkey. Flowers are pale blue, and bloom in springtime, beginning as early as February. These plants naturally grow in limestone or rocky soils in or near open pine and juniper woodlands. Individual plants reach up to 4-6 inches tall when mature and in bloom.

Crocus biflorus (Scottish Crocus, Silvery Crocus, Scotch Crocus)
White flowers with yellow throats and a purple stripe bloom in late winter. Some varieties will bloom in fall. There are many subspecies and varietals, a great deal of which are valued for their ornamental value in gardens. Individual plants reach up to 2-6 inches tall when mature and in bloom.

Crocus chrysanthus (Golden Crocus, Snow Crocus)
Flowers in this species are orange-yellow and sweetly fragrant. This species is native to the Balkans and Turkey. Hybrids come in a variety of flower colors including white, cream, yellow and blue marked with darker colors. The species true flower color is golden yellow. Blooms appear in springtime, and plants reach up to 2-4 inches tall when mature and in bloom. Varieties are outlined below:

'Advance'
With yellow flowers that have outer markings in purple.

'Blue Pearl'
Pale blue flowers.

'Cream Beauty'
Pale yellow flowers.

'E. P. Bowles'
This variety has yellow with purple featherings.

'Goldilocks'
Cream yellow flowers that have bronzey throats.

'Ladykiller'
Purple-edged white flowers with interiors that are white and purple.

'Princess Beatrix'
Blue flowers with a yellow center.

'Snow Bunting'
Pure white flowers.

'Prins Claus'
With white flowers that have blue to violet outer markings.

'Skyline'
With sky-blue flowers.

'Zwanenburg Bronze'
Golden yellow flowers with bronze outer markings.

Crocus corsicus (Corsican Crocus)
Found on Corsica and Sardinia, these island-dwelling Crocus flowers reach just under 4 inches tall when in bloom, and produce pale violet to reddish-purple slender fragrant flowers. Blooms pop in January through April. This species is popularly grown as a garden ornamental.

Crocus etruscus (Tuscan Crocus)
This species is endemic to woodland areas in Tuscany, and produces lilac-colored flowers with purple veining and prominent orange stigmas. Plants reach up to 4-8 inches tall. Blooms appear in late winter to early springtime. These plants are both widely cultivated as garden ornamentals and are considered endangered in their native habitat. 'Zwanenburg' is a popular ornamental cultivar.

Crocus goulimyi (Fall Crocus, Goulimy's Crocus)
Flowers are a deep lavender-blue, and this species needs warmth and excellent drainage. These plants are endemic to Greece, and bloom in fall, reaching up to 4 inches tall when mature and in bloom. The species is named for Greek amateur botanist and lawyer Constantine Goulimis. Variety 'Mani White' is a white-flowering choice ornamental perfect for garden cultivation.

Crocus imperati (Early Crocus, Imperati's Crocus)
Lilac interior and white with purple lined exterior flowers bloom in early spring. This species is endemic to Italy. Individual plants reach up to 3-6 inches tall when mature and in bloom. This species has naturalized in the northeastern United States, but is not considered invasive.

Crocus korolkowii (Korolkow's Crocus, Korolkow's Saffron, Celandine Crocus, Steppe Crocus)
This species has bright yellow to bronze-yellow flowers that bloom in late winter. This is an especially cold-tolerant variety, native to central Asia and northern Pakistan. These plants naturally grow in rocky soils and flower between February and May in their native habitat. These bulbs are commonly grown as ornamentals outside of their natural range. Popular cultivars include 'Dark Throat' and 'Kiss of Spring'. Noted as potentially invasive in California's Marin Headlands area.

Crocus kotschyanus (Crocus zonatus) (Kotschy's Crocus, Autumn Crocus, Fall Crocus)
These bloom in a pink-lavender color in early autumn, and are native to Turkey, The Caucasus, and Lebanon. Maximum height is just under 4 inches when in bloom. These flowers are popularly grown as garden ornamentals. Can become a nuisance in certain regions, but is not considered invasive.

Crocus ligusticus (Ligurian Crocus, Ligurian Saffron, Autumn Crocus)
Native to France and Italy, these interesting Crocus plants produce fringed, bright red-orange stigmas and lavender to lilac-colored flower petals. They are in bloom between September and October in their natural range, and are prized as garden ornamentals. Individual plants reach up to between 4 and 6 inches tall when mature and in bloom.

Crocus longiflorus (Long-Flowered Crocus, Yellow-Throated Crocus)
This species is native to Sicily, southwest Italy, and Malta, and reaches about 4 inches tall maximum. Flowers are purple to lilac in color and bloom in fall in this plant's native range. This species has been historically used as a Saffron substitute.

Crocus malyi (Maly Crocus)
Endemic to Croatia, this rare species produces white flowers with yellow throats, and blooms in early springtime. These plants are widely cultivated as garden ornamentals, and are protected in their native range. Maly Crocus reaches up to 2-4 inches tall when mature and in bloom.

Crocus mathewii
Native to southwestern Turkey, this perennial flowering plant produces flowers with white petals that darken to violet towards the base. Stigmas are bright orange and long. Individual plants reach up to 2-4 inches tall when mature and in bloom. Cultivars include 'Brian Mathew' and 'Dream Dancer'.

Crocus pulchellus (Hairy Crocus, Autumn Crocus, Beautiful Crocus, Pretty Crocus, Pretty Saffron, Mount Atos Crocus)
Pale lilac flowers with purple veins and a yellow throat bloom in fall. These plants are native to the Balkan Peninsula through Northwestern Turkey. These plants reach up to between 4 and 6 inches tall and wide when mature and in bloom.

Crocus sativus (Saffron Crocus, Autumn Crocus, Saffron)
In fall, lilac flowers bloom to reveal bright orange-red stigmas. This plant is the true Saffron plant; to harvest, pluck stigmas as soon as flowers open, then dry them and store them in glass or plastic vials. Divide corms when leaves turn brown and replant in fresh, improved soil. Individual plants reach up to 4-6 inches tall and wide when in bloom.

Crocus scardicus (Scardian Crocus)
This species of Crocus is native to eastern Europe, and flowers from May to July. Blooms are golden yellow, and these plants love to bloom near patches of snow in their native range. Flowers reach up to 3 inches tall when mature, and bloom in late spring to early summer in their native range, right as snow is melting.

Crocus sieberi (Snow Crocus, Sieber's Crocus, Cretan Crocus)
Lavender blue delicate flowers with a golden throat. An early winter bloomer, this species is native to the Mediterranean region, and is prized for its use as a hardy garden ornamental plant. These plants reach up to 3-6 inches tall when mature and in bloom.

Crocus speciosus (Bieberstein's Crocus, Autumn Crocus, Fall-Blooming Crocus)
These plants are native to northern and central Turkey, the Caucasus, northern Iran, Crimea, and Bulgaria. Vibrant blue-violet flowers bloom in early fall. This is one of the showiest Crocus species, and quickly multiplies, making it perfect for naturalizing in grassy areas. Variety 'Alba' has pure white flowers and other varieties have lavender and mauve blooms.

Crocus tommasinianus (Woodland Crocus, Early Crocus, Tommasini's Crocus, Tommies)
Flower buds are slender, and silvery lavender-blue flowers bloom early in the year. This is one of the smaller species of crocus, reaching just 3 inches tall when in bloom. These plants are native to Bulgaria, Hungary, Albania, and what was once Yugoslavia. Popularly grown ornamental varieties of this species include 'Ruby Giant', 'Whitewell Purple', 'Barr's Purple', 'Lilac Beauty', 'Albus', and 'Roseus'.

Crocus tournefortii (Tournefort Crocus)
This species is native to southern Greece and northern Crete, and reaches just under 4 inches tall when in bloom. Leaves are narrow and green, and flowers are light lavender to pale lilac in color, blooming in autumn and wintertime. These flowers are prized ornamentals.

Crocus vernus (Dutch Crocus, Spring Crocus, Giant Crocus)
These flowers come in shades of white, yellow, lavender and purple, often marked with darker stripes. This species blooms in late winter or early spring. This is the most vigorous Crocus species available for sale commercially, and is popularly grown as a garden ornamental in many climates. These hardy plants are native to the Alps, Pyrenees, and Balkans.

Caring for crocus

Choose a place in the landscape that receives full sun. They will flower best when they receive between 6 and 8 hours of sun each day. They prefer to have well-draining soil that is moderately fertile with a pH of between 6.0 and 7.0. They love a porous, light soil, and cannot stand having constantly wet roots. 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. Corms should be planted 2-3 inches under the soil and 2-4 inches apart with their pointed ends towards the sky. They are best when planted in groups instead of in a row or edging. These flowers are small and delicate, and are less impressive when they are planted singly. After planting, mulch around the base of the plant with organic mulching material to help retain soil moisture and suppress weed growth. Keep mulch away from the plant stems, as this can encourage an environment for root rot issues to take hold.

Each year in springtime, apply a 2-inch layer of organic compost around the planting area to improve soil structure, drainage, and nutrient load. This one feeding will be sufficient to carry the plants through their active growing and blooming seasons. These flowers do not require any pruning. Foliage will die back each year after creating energy for the plant's underground storage root. This can be removed, but it needs to be allowed to die back naturally. Crocuses should be divided every three to four years for best plant and root health. They can make a great lawn substitute in many areas, but will not naturalize where winters are warm.

Harvesting Crocus (Saffron)
Saffron Crocus (Crocus sativus) produces stigmas that are bright red-orange and harvested as a spice used in many dishes around the world. There are three stigmas per flower, and they are typically produced in fall (around October). The best time to harvest is on a sunny day in mid-morning after flowers have opened fully and are still fresh. The stigmas, also called threads, are laid out to dry for a few days in a warm place. They are typically stored in airtight containers for later use. To use, steep stigmas in hot liquid for about 20 minutes.

Propagation

Crocuses can be propagated either by division of existing corms or by seed. The division method will give you a plant that is genetically identical to the parent plant. To propagate your Crocus, follow the instructions below:

Propagating Crocus 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 Crocus 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 fall (after the plant has entered dormancy and been cut back). To propagate by division, follow these steps:

Gather your materials. Using a shovel, dig up your existing plant. Start from the outside and work your way in to avoid damaging the bulbs. Once you have worked it up out of the ground, lay it out.
Identify any smaller corms on the sides of the larger main corms. These can be removed from the plant and re-sown elsewhere. Make sure to use sterilized, sharp tools for cutting to avoid damaging the bulbs or spreading disease.
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 bulbs and water them in 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.