Have you ever found a stunning plant only to discover almost no information on it exists while there are hundreds of sites devoted to lawn grasses?
This is the curious fate of Ferraria crispa (fer-RAY-ree-uh KRISP-uh), a show-stopping plant from the Iridaceae family.
It has more names than web pages devoted to it.
Some of them are:
- Black flag
- Curled ferraria
- Starfish iris
- Starfish lily
- Sea Spider iris.
It’s also been sold under Ferraria obtusifolia and Ferraria undulata.
This perennial flower originated in South Africa. Yet it has become so common in Australia that it’s easy to think it’s from where it hails.
Starfish Iris Care
Size And Growth
While not a true iris or lily, it’s easy to see how it got those nicknames.
The plants form dense clumps, leading to corms that stack if not regularly thinned out.
Each plant is about 12″ to 18″ inches tall, and the plant tends to grow at a moderately slow pace.
Its sword-shaped foliage is an attractive blue-green.
Depending on your location and the plant’s mood, it may appear in spring and fall but die back in summer and winter. Or it might have a single growing season during the year.
Flowering And Fragrance
Sadly, the most striking aspect of this plant is also the most frustrating to describe.
Bloom times can vary greatly depending on the cultivar, variant, or location.
Your starfish lily may bloom anywhere from late winter to mid-summer, with some reports of it also blooming in the fall.
The velvety, frilly-edged flowers generally come in shades of yellow (with some instances of white, green, or brown), with spots that may be black, brown, or purple.
Each bloom is approximately 1 ½” inches across with three long petals and three shorter ones.
Multiple stem branches allow these blooms to appear in quick succession, and there are usually 2 to 3 branches per corm.
The total bloom time can last for over a month, but individual flowers only last a day.
Be careful to ask about the specific scent before purchasing a plant from growers.
Some starfish irises have a sweet vanilla scent to attract butterflies and hummingbirds.
Yet others have a scent closer to rotting meat, meant to attract pollinating fly species.
Light And Temperature
This plant prefers full sun but may enjoy some afternoon shade in harsher climates.
It can be grown outdoors in USDA hardiness zones 3 to 11.
You will need to overwinter the corms indoors in zones 3 to 8. Those in zones 9 to 11 may remain on the ground.
They’re not frost-hardy but can grow in a temperature range of 40° to 75° degrees Fahrenheit.
When possible, nighttime temperatures of around 65° degrees Fahrenheit are ideal.
Temperatures above 75° degrees Fahrenheit will cause the plant to go dormant.
Watering And Feeding
These plants like soil consistently moist but not wet, making the soak-and-dry method perfect.
Follow these tips:
- Water when the soil feels dry 1″ inch down, going slowly until the earth can no longer absorb at the same speed you’re pouring.
- Stop when you see moisture seeping from the drainage holes for container plants.
- Cut back on watering if the plant goes dormant during the summer and late in autumn to give the soil a chance to dry out before storing the corms.
- A balanced liquid houseplant fertilizer cut to half strength works well. But you’ll need to learn the growth cycle of your particular plant to adjust its feeding schedule appropriately.
- Give the first feeding about 2 to 3 weeks after new growth appears.
Extra feedings will be determined by whether the plant continues to grow into summer (at which point you’ll need to feed it again 2 to 3 months after the first feeding) or is dormant in summer and active in fall (at which point, provide once as you did in spring).
Soil And Transplanting
Fast-draining, sandy to loamy soil works best.
You can mix coconut coir and perlite into your garden soil to achieve this consistency.
A mix of 1 part African violet to 2 parts coarse sand or perlite will work for potted specimens.
Divide these plants every 3 to 5 years, or the corms become so overcrowded that they limit the blooms.
Be sure to dig about 12″ inches below the corm level when excavating your garden to turn the soil and avoid harming any corms.
Grooming And Maintenance
Very little maintenance is needed outside of removing dead or diseased leaves.
How To Propagate Black Flag?
Because of how varied this plant can be, with many cultivars listed without a cultivar name, it can be a bit of a gamble when using seeds to cultivate unless you don’t mind a possible surprise plant.
Yet, the division is a perfect way to get more of the same plant.
You will be harvesting corms every 3 to 5 years anyway, so why not use them?
Starfish Lily Pests Or Diseases
At first, these plants may sound finicky, as they have a low tolerance to the following:
But give them a sunny spot with moderate temperatures, and they’ll thrive.
Some breeds will also attract butterflies and hummingbirds, and the plant is deer-resistant.
Starfish lilies can suffer from the usual aphid or mealybug infestation when it comes to pests, albeit rare.
Slugs and snails are a more common foe. You may have to deal with flies if you have a cultivar or variant that uses them for pollination (these will have a pungent flower smell).
Iris root rot is the primary disease risk, although fungal infections may occur if the plant is overwatered or water is allowed to sit on the leaves.
This plant is toxic to both humans and pets if ingested.
Ferraria Crispa Uses
These attractive plants are perfect for many garden themes, from coastal and borders to rock gardens.