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Crocosmia
Crocosmia is a striking summer-blooming perennial known for its vibrant, funnel-shaped flowers and sword-like foliage. This genus of the iris family (Iridaceae) grows from bulb-like corms and adds a tropical flair to temperate gardens. Clusters of red, orange, or yellow blossoms arch gracefully on wiry stems, creating a fiery display that attracts hummingbirds and butterflies. Most Crocosmia varieties feature warm colors, though some cultivars produce golden yellow flowers that offer a different look. Crocosmia stands out among other types of flowers because of its bold coloring and dynamic form. While classic garden blooms like roses, tulips, or sunflower often take center stage, Crocosmia offers a unique visual impact with its cascading sprays of warm-toned blooms. Also commonly called montbretia, this plant is prized by gardeners for being relatively low-maintenance and deer-resistant. Its brilliant red flowers and orange flowers provide long-lasting color from midsummer into fall, making Crocosmia a favorite for vibrant border plantings and cut flower arrangements.
🌱 Taxonomy and origin
Crocosmia is a small genus in the iris family, with seven known species originating from southern and eastern Africa. These plants naturally inhabit grasslands from South Africa up through Sudan, with one species found in Madagascar. The genus name comes from Greek “krokos” (saffron) and “osme” (smell), referring to the saffron-like scent released by dried Crocosmia flowers when immersed in water. Common names for Crocosmia include montbretia (especially for the hybrid Crocosmia × crocosmiiflora), as well as coppertips and falling stars. Montbretia became a popular garden plant in Europe in the late 19th century after French horticulturists bred hybrids from wild African species. Today, Crocosmia is cultivated worldwide, valued for its exotic appearance and ease of growth outside its native range.
🌸 Bloom time
Crocosmia plants typically bloom from mid-summer into early fall. In many regions they begin flowering by July, reaching peak display in late summer and often continuing until the first autumn frost. Each arching flower spike carries multiple buds that open in succession, so a single stem can provide color for one to two weeks. The overall blooming period can last for a month or more as new stems keep emerging. By mid-summer, when spring beauties like peonies and camellia have finished, Crocosmia steps in to light up the garden with its vivid blossoms. The timing makes it an excellent choice to extend floral interest into the later season. Gardeners can deadhead the plant by removing spent flowers to tidy it up, although Crocosmia often continues producing some blooms regardless. In warm climates with long summers, certain varieties may rebloom or flower sporadically again in early fall.
📏 Height and spread
Depending on the variety, Crocosmia typically grows between 2 to 4 feet tall (about 0.6 to 1.2 meters). The popular red cultivar ‘Lucifer’ is on the taller end, often reaching around 3 to 4 feet in height, whereas some other cultivars stay closer to 18 to 24 inches (45 to 60 cm). The sword-like leaves emerge from the base and may rise over 2 feet long, forming an upright clump. Each plant’s spread is usually about 1 to 2 feet (30 to 60 cm) after a couple of growing seasons. Crocosmia corms multiply relatively quickly, causing clumps to expand and become crowded over time. Gardeners often plant corms in groups spaced roughly 6 to 8 inches (15 to 20 cm) apart to create a full, showy cluster. In exposed sites, tall flower stems may appreciate staking, but generally the stems are sturdy enough to stay upright in normal conditions.
☀️ Light
Full sun is ideal for Crocosmia to reach its full flowering potential. Aim for at least 6 to 8 hours of direct sunlight per day. In bright, sunny conditions, the plants produce more blooms and sturdier stems. They can tolerate partial shade, but too little sun often results in fewer flowers and lankier, floppy foliage. In deep shade, Crocosmia will survive but may not bloom much at all. In very hot climates such as zones 9 to 10, providing a bit of afternoon shade can help prevent leaf scorch and prolong the flowering period, but overall these plants thrive with abundant light. Planting Crocosmia in an open area, similar to where you might grow other sun-loving summer bulbs, will ensure it gets the exposure it needs to develop vibrant flower spikes.
💧 Water
Crocosmia performs best with moderate watering and soil that stays lightly moist during the growing season. These plants appreciate consistent moisture, especially while budding and flowering, but they do not tolerate soggy or waterlogged conditions. Good drainage is crucial to prevent rot of the corms. Water deeply about once a week during dry spells, providing roughly 1 inch (2.5 cm) of water per week in total including rainfall. Allow the top inch of soil to dry out between waterings to ensure the roots get air. Once established, Crocosmia can handle brief periods of drought, but prolonged dry conditions may cause the foliage to brown or flowering to diminish. Mulching around the plants can help conserve soil moisture and keep the roots cooler in hot weather.
🌍 Soil and pH
Plant Crocosmia in well-draining soil to keep its corms healthy. A loamy or sandy soil enriched with organic matter works best, as it holds enough moisture without becoming waterlogged. If your garden has heavy clay soil, consider amending it with compost or grit to improve drainage, since overly wet soil can lead to root and corm rot. In terms of soil chemistry, Crocosmia is not very fussy: it thrives in neutral to slightly acidic conditions. An optimal pH range is around 6.0 to 7.0. The plants can tolerate slightly alkaline soil as well, though extremely chalky soil may require added organic matter to maintain nutrient availability. Overall, average garden soil is usually sufficient as long as it doesn’t stay too soggy. Adding a layer of compost each spring can help improve soil structure and fertility for better growth.
❄️ USDA hardiness
Most Crocosmia varieties are winter-hardy in USDA hardiness zones 6 through 9. In these regions, the corms can safely overwinter in the ground and resprout each spring. Some especially hardy cultivars, such as ‘Lucifer’, can survive in zone 5 if provided with a thick layer of mulch for insulation during the winter. In zone 5 or colder, Crocosmia is generally not hardy in the ground. Gardeners in those areas often treat it as a tender summer bulb: plant the corms in spring and then dig them up in fall before hard freezes. Store lifted corms in a cool (around 40°F, or 4°C), dry place over winter and replant when the weather warms. In very warm climates (zone 10 and above), Crocosmia may remain evergreen, but it will benefit from a cooler dry rest period if possible. Ensuring proper winter drainage to avoid waterlogged soil is also key to cold survival.
🌼 Propagation and longevity
Crocosmia naturally propagates itself by producing new corms, called cormels or offsets, around the base of the old ones. Over time, a single planted corm will form a clump of many corms. The easiest way to propagate Crocosmia is by division. Every 2 to 3 years, or whenever flowering starts to decline, dig up the clump in early spring or after flowering. Gently separate the corms, making sure each division has a healthy top corm and some roots, then replant them at the same depth to start new clusters. The plant can also grow from seeds found in the dried seed pods, but seed propagation is slow and may not produce flowers for a few years. Moreover, hybrids grown from seed usually do not match the parent plant.
In terms of longevity, Crocosmia is a long-lived perennial. As long as the corms are not killed by extreme cold or rot, a clump can persist and even expand for many years. Some established plantings will come back reliably each season for decades, especially in climates where they thrive. Regular division keeps them vigorous. However, extremely congested clumps may produce fewer flowers, so periodic thinning benefits the plant’s long-term bloom performance. In favorable climates, Crocosmia can even naturalize, spreading beyond its original planting site if left unchecked, especially in mild climates. Crocosmia’s overall vigor means it rarely suffers from any serious issues when grown in proper conditions. If growing in containers, plan to divide or repot every few years to refresh the soil and prevent overcrowding of corms.
👃 Fragrance
Despite its vibrant appearance, Crocosmia is not particularly known for fragrance. The blossoms generally have little to no noticeable scent to the human nose. Gardeners do not grow Crocosmia for perfume like they might grow roses or jasmine; instead, the appeal is in the bright color and form of the flowers. Interestingly, the name Crocosmia references a saffron-like smell released when dried Crocosmia flowers are steeped in warm water, but in the garden you will rarely detect any aroma from fresh blooms. A few cultivars are reported to have a very mild sweetness if sniffed closely, but overall this plant won’t add fragrance to your garden. Its main attraction lies in its visual impact and its ability to lure in hummingbirds with vivid, tubular flowers rather than scent.
⚠️ Toxicity and pet safety
Crocosmia is generally considered non-toxic to humans and is not listed among common poisonous garden plants. For pets, it is also regarded as a low-risk plant. Unlike some bulbs such as calla lily or tulips that can be quite toxic to cats and dogs, Crocosmia does not contain known dangerous compounds. If a curious pet or child were to chew on the leaves or flowers, it might experience mild stomach upset or vomiting, but severe reactions are unlikely. Of course, it’s still best to discourage animals from eating any ornamental plant, as even non-poisonous plants can cause minor digestive irritation. In normal garden use, Crocosmia is a pet-friendly choice, and there are no reported cases of serious poisoning from this plant. Gardeners can confidently plant it in yards where pets play, keeping in mind basic precautions such as preventing pets from digging up and eating the corms.
🌿 Vase life
Crocosmia’s striking stems make excellent cut flowers. In a vase, the blooms have a relatively long life, typically lasting about 7 to 10 days with proper care. To maximize vase life, cut the stems when the lowest flower buds are just starting to open while the upper buds remain closed. Strip off any foliage that would be below the water line, and place the stems immediately in fresh water. Using a clean vase and adding floral preservative can help keep the water clean and extend the freshness of the flowers. Crocosmia’s florets will continue to open in succession along the spike, so an arrangement can remain showy as new blossoms replace the spent ones. Changing the water every few days and recutting the stem ends will also prolong their appearance. Although Crocosmia stems do not bring fragrance to an arrangement, they add vibrant color and an interesting, arching form that draws the eye in mixed bouquets.
🐛 Pests and diseases
Crocosmia is relatively problem-free in the garden. Few pests find its tough, sword-like leaves appealing. Deer and rabbits usually leave Crocosmia alone, which is a boon in areas with browsing wildlife, likely because the foliage is not very palatable. In terms of insects, the most common pest is red spider mites, which can sometimes infest the foliage during hot, dry weather. Mite damage appears as fine speckling or webbing on leaves. If noticed, it can be managed by hosing down the plant or using insecticidal soap. Aphids might occasionally cluster on flower buds or stems, but they are not typically severe. A strong water spray can knock them off. Overall, serious insect infestations on Crocosmia are rare with proper care.
As for diseases, the main issues are related to moisture. Corm rot, caused by fungi in overly wet soil, can occur if drainage is poor. Ensure soil is well-drained to avoid rot. Occasionally, a fungal leaf spot or rust may develop, showing brown or orange speckles on leaves. Removing affected foliage and improving air circulation helps prevent spread. Crocosmia can also contract viral diseases, which cause mottled or streaked foliage. These viruses are often spread by sap-sucking insects like thrips. If a plant shows mosaic-like discoloration and stunted growth, it’s best to remove it to protect other plants. Maintaining healthy conditions such as full sun, adequate spacing, and avoiding overwatering will minimize any pest or disease problems. Crocosmia’s overall vigor means it rarely suffers from any serious issues when grown in proper conditions.
FAQs
When should I plant Crocosmia corms?
Plant Crocosmia corms in the spring, once the danger of hard frost has passed and the soil begins to warm. In most regions, this means mid-spring (around April or May). If you live in a mild climate, you could also plant in early fall for establishment before winter, but spring planting is more common to ensure a strong start. Choose a sunny, well-draining site and bury the corms about 3 inches (7 to 8 cm) deep, with the pointed side or sprouting side facing up. Space each corm roughly 6 to 8 inches (15 to 20 cm) apart so they have room to multiply. Planting in groups of 5 or more corms will create a nice clump for a showy display. After planting, water the area and keep it moderately moist as the corms wake up and begin to grow.
Can I grow Crocosmia in pots or containers?
Yes. Crocosmia can be successfully grown in containers as long as the pot is deep enough to accommodate its roots and corms. Choose a container that is at least 12 inches (30 cm) in diameter and depth, with good drainage holes. Use a well-draining potting mix (you can mix in some sand or grit to improve drainage). Plant the corms about 2 to 3 inches deep in the pot, and water them in. Place the container in full sun for best growth and flowering. Be mindful that potted Crocosmia will dry out faster than those in the ground, so check soil moisture regularly and water when the top inch is dry. Fertilizing lightly in spring can help with bloom production in a pot. Crocosmia may not grow quite as tall in a container, but it should still produce its bright flowers. In cold climates, you can move the pot into a garage or indoors over winter, or dig up and store the corms from the pot to replant the next spring.
Will Crocosmia come back each year?
If you live in a climate that suits Crocosmia’s hardiness, the plant will come back year after year. In USDA zones 6 through 9 (and even zone 5 with protection for some varieties), Crocosmia behaves as a returning perennial. The corms survive underground over winter and sprout new growth each spring. In fact, they often multiply, so a clump can become larger and produce more blooms with each passing year. However, if you are in a region with very cold winters (colder than zone 5), Crocosmia corms left in the ground will likely not survive freezing temperatures. In those areas, gardeners either treat Crocosmia as an annual (plant new corms each spring) or dig up the corms in the fall to store indoors until replanting time. With proper care and the right climate, Crocosmia can be a long-lived addition that reliably returns every growing season.
Is Crocosmia invasive, or will it spread a lot?
Crocosmia does spread over time, but whether it’s considered “invasive” depends on the location and how you manage it. In a garden setting, Crocosmia corms multiply and form larger clumps year by year. This means a planting can expand and become crowded if you never divide it. However, it usually spreads in a relatively controlled clump rather than taking over the entire garden. You might find new shoots popping up a few inches away from the main clump as corms grow and split. In certain mild, damp regions (for example, parts of the UK or Pacific Northwest), the common montbretia (Crocosmia × crocosmiiflora) has escaped gardens and naturalized in the wild, which is why it’s labeled invasive there. In a typical home garden, you can keep Crocosmia from becoming a problem by digging up and thinning the corms every few years. That way, you prevent the clump from overtaking neighboring plants. Overall, Crocosmia is a vigorous grower and will spread in its area, but it’s manageable with occasional maintenance.
Why is my Crocosmia not flowering?
When Crocosmia fails to bloom, a few common issues could be the cause. One frequent reason is insufficient sunlight. Crocosmia needs plenty of sun (around 6 or more hours a day) to produce flowers. If it’s planted in too much shade, you’ll get foliage but few or no blooms. Another cause can be overcrowding. If the corms have multiplied and become too congested, the plant may bloom less; dividing the clump to give each corm some space often restores flowering. Soil nutrition is another factor: excessively rich soil or too much nitrogen fertilizer can lead to lots of green leaves at the expense of flowers. Make sure the soil is well-draining as well, because waterlogged or rotten corms won’t flower properly. Also consider the plant’s age and origin. Crocosmia grown from very small corms or from seed might take an extra year to reach blooming size. By ensuring enough sun, periodically dividing overcrowded clumps, and avoiding over-fertilization, you can encourage your Crocosmia to bloom reliably.
Do hummingbirds like Crocosmia flowers?
Yes, hummingbirds are very attracted to Crocosmia. The plant’s bright red and orange tubular flowers are like beacons for hummingbirds, which have long beaks perfectly suited to sip the nectar inside each tube-shaped bloom. Many gardeners report that red varieties like Crocosmia ‘Lucifer’ are especially good at drawing in hummingbirds to the yard. During Crocosmia’s blooming season (midsummer), you’ll often see these tiny birds hovering around the arching flower spikes to feed. In addition to hummingbirds, Crocosmia can also appeal to other pollinators like butterflies and bees, though hummingbirds tend to show the most enthusiasm. If you want to attract hummingbirds, planting Crocosmia among other hummingbird-friendly red flowers and orange flowers can create a vibrant, wildlife-friendly garden display. Just be sure to place the Crocosmia in a sunny spot where the birds can easily find the flowers.
Are Crocosmia plants deer-resistant?
Generally, yes. Crocosmia is considered deer-resistant. Deer and rabbits tend not to favor the tough, iris-like leaves or the corms of Crocosmia, likely because of the texture or taste. In gardens where deer frequently browse, Crocosmia often goes untouched even when other more tender types of flowers get nibbled. This makes Crocosmia a useful choice for adding color in areas with deer activity. Of course, it’s important to note that no plant is completely deer-proof; a very hungry deer will sample almost anything if food is scarce. However, in most cases you can expect Crocosmia to be left alone. Gardeners in rural or deer-populated regions often report that their Crocosmia clumps persist and bloom without being damaged by wildlife, especially when planted among other deer-resistant plants.
How do I overwinter Crocosmia in cold climates?
If you garden in a region colder than Crocosmia’s usual hardiness, you have a couple of options to save your plants over winter. One method is to dig up the corms in the fall. After the first frost has killed back the foliage, cut off the spent leaves a few inches above the corm. Then carefully lift the clump of corms out of the ground with a garden fork or trowel. Brush off excess soil and let the corms air-dry for a day or two in a cool, dry place (out of direct sun). Once dry, store the corms in a breathable container (like a cardboard box or paper bag) filled with dry peat moss, wood shavings, or crumpled newspaper. Keep this storage box in a cool, frost-free location. Around 35 to 50°F (2 to 10°C) is ideal for the winter. Alternatively, if you only get borderline cold (say zone 5), you might try leaving the corms in the ground under a heavy layer of mulch for insulation. Just know that this is less reliable. If Crocosmia is in a pot, you can move the whole pot into an unheated garage or basement until spring. When spring arrives, replant or bring the corms/pots back outdoors and they should start growing again.
Can I grow Crocosmia from seeds?
It’s possible to grow Crocosmia from seed, but it requires patience. Crocosmia seeds can be collected from the dried seed pods that form after the flowers fade. You can sow these seeds in pots or trays, either in the fall (to naturally stratify outdoors over winter) or in spring after the last frost. Use a well-draining seed mix and barely cover the seeds, keeping the soil moist but not waterlogged. The seeds should germinate within a few weeks to a couple of months depending on conditions. Keep in mind that if the seeds come from hybrid varieties, the resulting plants may not look exactly like the parent (they can have variable flower colors or sizes). It typically takes at least 2 to 3 years for a seed-grown Crocosmia to mature enough to produce blooms. Because of this long timeline, most gardeners prefer to plant corms for quicker results. However, growing from seed can be a fun way to obtain a lot of plants or to see what new variations might appear.
Interesting tips
- Choose a sunny spot for planting. Crocosmia thrives in full sun and will produce the most flowers with 6+ hours of direct light. In too much shade it can survive but will have sparse blooms and may flop over.
- Plant crocosmia corms in groups rather than singly. Clumping 5 or more corms together in one area creates a brilliant mass of color that has far greater impact than a single stem here or there.
- Make sure the soil drains well. If you have heavy soil, consider raised beds or mix in grit and compost. Good drainage prevents the corms from rotting during wet periods, especially over winter.
- Divide clumps every few years. Dig up and split congested Crocosmia clumps in early spring or after flowering to keep plants vigorous. Regular division will encourage better blooming and prevents the clump from becoming overcrowded.
- Provide winter protection in colder zones. In USDA zone 5, mulch over the Crocosmia bed with straw or leaves after the ground freezes to help the corms overwinter. In even colder zones, remember to lift and store the corms indoors.
- Support tall varieties if needed. If your Crocosmia (like the 4-foot ‘Lucifer’) is planted in a windy or exposed spot, use discreet stakes or rings to keep the flowering stems upright. In calm, sunny locations they usually support themselves.
- Pair Crocosmia with contrasting colors in the garden. The intense orange and red blooms look stunning against cool-toned blue flowers or purple flowers (for example, near a planting of hydrangea macrophylla with blue blooms). The fiery colors also pop when backed by neutral white flowers or even nearly black flowers for a dramatic effect.
- Mark the spot where you plant the corms. Crocosmia foliage dies back in winter, so it’s easy to forget where they are planted. Put a small stake or label in the ground to avoid accidentally digging in that spot during the dormant season.