- Crocosmia Planting Guide
- Choosing a Site
- Soil Prep
- When to Plant
- How to Plant Crocosmia Corms
- During the Season
- At Season’s End
- Dividing Older Plants
- Insider Tips
- How to grow crocosmias
- Garden Plans For Crocosmia
- Planting Companions
- Crocosmia Care Must-Knows
- Cut-Flower Tips
- More Varieties of Crocosmia
- Learn How To Plant, Care and Grow Beautiful Crocosmia
Crocosmia Planting Guide
Crocosmia are South African relative of the familiar gladiolus. You can see it in the foliage. Same narrow, sword shape. Leaves that originate near the base rather than along the stem. Crocosmia were brought to Europe in the mid-1800s and became increasingly popular over time. By the 1920s, hundreds of crocosmia cultivars had been created and flowering clumps could be found in most flower gardens.
Everything changed with the onset of World War II. During that period, gardeners were encouraged to “Dig for Victory” and to replace ornamental gardens with vegetable plots to support the war effort. Crocosmia, or montbretia as this plant is called in Europe, was uprooted and tossed in the compost heap. With time, crocosmias have made a comeback and are increasingly included in mixed perennial borders. Hip, hip, hurrah!
Choosing a Site
Crocosmia prefer full sun sites in most of the country, but do appreciate a bit of afternoon shade in the hottest regions. These plants thrive in moderately fertile, well-drained soil. Where happy, they may naturalize and spread. Crocosmia are good choices for breezy sites because their foliage bends with the winds rather than breaking.
Average to rich soil with medium amounts of moisture will support healthy crocosmia. These plants do not thrive in hot, dry environments. Adding a slow release fertilizer when you plant can be helpful if your soil is a bit lean.
When to Plant
Plant crocosmia corms outdoors when frost danger has past and the soil has warmed. Once established, crocosmia can manage moderately cold weather.
How to Plant Crocosmia Corms
The corms of crocosmia look a bit like large crocus bulbs, with pointed tops and bottoms that are often slightly indented. The bottoms also can be identified because there’s sometimes a dark circle there. Plant with the points facing upwards and cover with 3-4” of soil. Water well to settle the soil around the corms. A light mulch that helps hold soil moisture, but does not lean against the stems (can promote stem rot) is often helpful.
Crocosmia corms can take 3-5+ weeks to begin to sprout depending on soil temperature and moisture levels. Typically, the corms vary in sprout timing so don’t worry if a few show up and the others take their time. Patiences is helpful the first season.
During the Season
Crocosmia plants take a few seasons to fill out into nice big clumps. Give the bulbs water every few days as they settle in, assuming Mother Nature doesn’t take care of that for you, and expect to see slender blade-like sprouts in a few weeks.
Crocosmia require about an inch of moisture total weekly and beside that, need little care during the growing season. You can trim off spent flowers to keep the plants looking their best. Feel free to cut flowers and buds for arrangements.
At Season’s End
Late in the fall, or in the spring before new growth appears, trim your crocosmia foliage to an inch or two above soil level. This will allow the fresh leaves to grow unencumbered and will keep your garden looking neat.
Dividing Older Plants
When crocosmia clumps grow large they may be divided for rejuvenation and for additional plants. Dig, split with a shovel and replant in spring just as the new season’s sprouts are beginning to appear. Water daily for a week while the plants resettle. Flowering may be reduced that first season as the plants reestablish.
- Hummingbirds love crocosmia flowers.
- The buds of crocosmia are unusual; colorfully banded. Snip some for snazzy additions to bouquets. Flowering stems are best cut when the lowest blooms have just begun to open.
- Crocosmia can be slow to settle in and typically become fuller clumps in the second and third summers. If your plants are a bit on the thin side their first summer, don’t worry. They’ll fill out in subsequent seasons as the roots produce additional corms and those produce sprouts to thicken the clump.
- Feel free to trim off any brown leaf tips that might develop late in the season. This is an esthetic option, completely up to you.
- Crocosmia bloom for about two months, from early June into August. All varieties are in bloom by July 4th which has earned them the common name “firecracker flowers”.
How to grow crocosmias
Crocosmias are guaranteed to spice up your borders with their small bright flowers in zingy citrus shades.
There are hundreds to choose from, in varying sizes, so they’ll suit gardens of all sizes. The foliage is also very ornamental – the clumps of upright, strappy, bright green leaves are great for punctuating mixed borders. The sprays of flowers that follow appear from June onwards, into late summer and are good for cutting. Although if left, the small seedpods can be quite decorative.
Crocosmias are also known as montbretia, although this tends to refer to the common species Crocosmia x crocosmiiflora that has naturalised in many areas, and is considered to be invasive. The cultivated varieties are less likely to become invasive.
Take a look at our handy crocosmia Grow Guide, below.
Where to grow crocosmias
Crocosmia corms ready for planting
Crocosmias are South African in origin, and require fertile, well-drained soil. They prefer full sun, but will tolerate light shade. Although they love warmth, they also need a reasonable amount of moisture, so make sure that you choose a spot with well-cultivated soil that doesn’t dry out. In colder parts of the country, choose a sheltered site.
Planting crocosmia corms
Crocosmias are corms and can be planted like bulbs. Dig a generous hole, about 7-10cm deep and add a spadeful of well-rotted compost. Plant a handful of corms a few centimetres apart so that you start out with a reasonable clump and cover with soil.
Crocosmia ‘Star of the East’
If you want to increase your stock of crocosmia, lift clumps in spring. The corms multiply over the years and when you dig them up you will find a distinctive string of conjoined corms. Gently pull this apart and plant up the top two which will be the newest and therefore make the most vigorous plants.
Crocosmias can succumb to red spider mite, but are otherwise generally pest and disease-free.
Caring for crocosmias
Mulch crocosmia corms in autumn to protect them over winter and keep well watered during dry spells through the summer. Crocosmia corms multiply readily, so clumps will become congested and flower less vigorously over time. The best time to divide congested clumps is in spring. Watch our video on splitting up a clump of crocosmia.
Crocosmia varieties to grow
Crocosmia ‘Citronella’ Advertisement
- ‘Emily McKenzie’ – a compact crocosmia. The bright orange flowers have an attractive mahogany throat. Foliage is a slightly darker green and it can be slightly less hardy than other varieties
- ‘Citronella’ – with upright, fresh green leaves and small, soft yellow luminous flowers
- ‘Hellfire’ – bears tight clusters of enormous, bright crimson flowers from mid-summer to autumn
- ‘Lucifer’ – with tall, arching sprays of intense, fiery red blooms. The first true red cultivar, ‘Lucifer’ is one of the tallest varieties growing up to 1.5m. The pleated leaves are also attractive in their own right and the seedheads can look decorative if left
- ‘Harvest Sun’ – a relatively new hybrid, bearing large orange-red flowers in contrast with upright, fresh green foliage
- ‘George Davison’ – at 60cm, this medium height crocosmia bears upright stems of golden yellow, freesia-like flowers from late-summer to autumn
Calling all hummingbirds! Crocosmias’ graceful arching stems of petite red, orange and yellow flowers are beacons to hummingbirds in search of a nectar rich meal. These easy-to-grow corms (a bulb-like structure) unfurl their fiery flowers in midsummer and fall when the rest of the garden is often languishing in the heat. Count on crocosmia, also called montbretia, to add a burst of color and whimsical interest year-after-year.
Garden Plans For Crocosmia
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Crocosmia’s sword-shape leaves and thin, arching stems offer great contrast to other garden plants in beds and containers. Plant a clump of crocosmia alongside other boldly colored late-summer bloomers such as black-eyed Susan (Rudbeckia hirta), coreopsis, dahlia, and blanket flower (Gaillardia × grandiflora). Contrasting color companions include aster, flowering tobacco (Nicotiana sylvestris), and globe thistle (Echinops bannaticus).
Crocosmia Care Must-Knows
Crocosmia is hardy in Zones 6 through 10. Some nurseries stock small crocosmia plants in nursery pots but the greatest selection of crocosmia cultivars is usually available as corms. These bulblike structures are planted in spring or fall. When planted in spring, they may not bloom until the following season.
Plant crocosmia corms 3 to 5 inches deep and 6 to 8 inches apart in full sun and moist, well-drained soil that is rich in organic matter. Prior to planting, you may need to enrich the soil by incorporating a 2-inch layer of well-decomposed compost. For the best bloom show and quick, easy planting, plant a dozen or more of the same cultivar in a trench.
Staking is sometimes required for the tallest crocosmia cultivars. Sink a stake into the ground near the corms and loosely tie about three flower stems to it using garden twine. Crocosmia is known for its ability to multiply quickly. Plan to dig and divide corms every three or four years in early spring just before growth starts. Replant the corms or share extras with friends.
Learn how organic matter helps your soil—and plants!
Crocosmia’s arching stems make it a unique addition to any flower arrangement. Give this plant extra care right after cutting and it will last for more than a week in a vase. First, cut stems when the first few flowers at the bottom of the spike are just opening. Remove the leaves from the stems and recut them. Immerse the stems in warm water up to the point where the flowers emerge. Place the vase in a cool, dark place for 48 hours, then move it to a bright spot and enjoy your handiwork.
Check out these unique vases to make your flower arrangements showstoppers.
More Varieties of Crocosmia
‘Ember Glow’ crocosmia
Crocosmia x crocosmiiflora ‘Ember Glow’ has vibrant upward-facing scarlet flowers that open wide to reveal golden throats. Zones 6-9
Crocosmia ‘Lucifer’ offers arching spikes of scarlet flowers in mid- to late summer. It grows 3 to 4 feet tall. Zones 6-9
Crocosmia ‘Meterore’ bears bright yellow-orange blooms with red throats. It grows 3 feet tall. Zones 6-10
Learn How To Plant, Care and Grow Beautiful Crocosmia
Extremely showy and exotic-looking, Crocosmia produce decorative clumps of erect sword-shaped leaves and brilliant wands of fiery scarlet, red, orange, and yellow tubular flowers which bloom for 5-8 weeks from mid summer through mid fall. Easy to grow, they stand proud and bold provided some basic rules are respected.
1. Select The Right Site
- Best flowering occurs in full sun or partial shade. Crocosmia will survive in part shade but best flower production is obtained in full sun – except in hot summer climates where part shade will enable the flowers to last longer.
- Plant in fertile, humus-rich, moist but well-drained soil. Crocosmia do not enjoy hot, dry sites.
- Choose a spot sheltered from cold drying winds.
2. Planting Your Crocosmia
- Crocosmia corms should be planted in spring after all danger of frost is gone.
- If conditions are cool or soil temperature is cold, delay the planting until the soil has warmed up.
- Plant your Crocosmia corms 2-3 in. deep (5-8 cm) and space them 6-8 in. apart (15-20 cm) when planted in groups – 18-24 in. away (45-60 cm) from the other plants.
- Set the Crocosmia corms with the pointy end facing up. Cover it and press the soil down around the roots and water the planting area thoroughly.
- Add a thick, dry, organic mulch to keep the soil moist and protect our crocosmias in winter.
Crocosmia ‘Star of the East’
- Water your crocosmias once weekly during the growing season, so the soil remains evenly moist.
- Remove spent blooms to encourage new blooms. Cut the stems back to where they meet the leaves.
- After blooming is over, keep the leaves so that the plant can put its energy back into its bulb for next summer’s blooming. The leaves give an energy charge to the bulb through photosynthesis and for this they need to keep their leaves!.
- Cut back the foliage almost to ground level when the leaves wither and die back.
- Propagate by division in spring just before growth starts.
- Crocosmia should only be divided every 3-4 years (in late summer or early fall), to restore vigor and increase flower production.
Crocosmia ‘George Davison’
Crocosmia ‘Carmin Brilliant’
- Most Crocosmias are winter hardy in zones 6-9, so in these climate zones the corms can be left right in the ground. Some species, including Lucifer, are hardy in zone 5.
- If you live in a colder area and you want to save your corms for next spring, you may dig them up before the first frost and store them over winter before replanting them next spring. Not sure about your growing zone? Check here.
- Remove surplus soil, dry and then store in trays in a cool place – between 35°F and 45°F (2°C and 7°C).