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Gladiolus murielae—Without Doubt a Beautiful Flower

by Bruce Crawford, Manager of Horticulture, Morris County Park Commission
Zoom in Gladiolus murielae.
The six tepals, showcasing the central purple blotch.

Tender or nonhardy bulbs for summer display are a group of plants many gardeners appear to avoid. The reasons I can only speculate, but perhaps the effort of digging the plants come autumn and overwintering the bulbs indoors is perceived as too much work? Or, are many of these plants simply unknown? This knowledge barrier is often compounded by changes in the botanical names or the marketing of the plants under incorrect names. A case in point is Gladiolus murielae or the Abyssinian Gladiolus. Providing beautiful flowers for the mid and late summer garden, this often mislabeled plant is far too little known and used.

Gladiolus are members of the Iridaceae or Iris Family with around 300 species found throughout Asia, northern regions of the Mediterranean, South Africa, and tropical regions of Africa. Gladiolus murielae is native to Eastern Africa from Ethiopia south to Malawi. The genus was first published in 1753 by the Swedish botanist Carl Linnaeus (1707–1778). Gladius is Latin for sword and its diminutive form is Gladiolus, meaning little sword. Linnaeus was clearly struck by the similarity of the pointed foliage to the shape of a small sword! Unfortunately, confusion with the identity of Abyssinian Gladiolus began at the very start when it was originally named Acidanthera bicolor. It was initially described in 1844 by the German botanist and minister Christian Ferdinand Friedrich Hochstetter (1787–1861). The genus name was conceived from the Greek Akic for sharp point and Latin Anthera for anthers, describing the three sharply pointed anthers as seen Picture 2. The specific epithet of bicolor comes from the prominent central purple blotch on the otherwise white flowers (as seen in Picture 1).

Zoom in Gladiolus.
Picture 2: The three pointed anthers and long style with 3-part reflexed stigma.

Aside from the sharply pointed anthers, the flowers also have a distinctive long red floral tube as seen in Picture 8, which is unusually long for Gladiolus and explains why it was initially not placed within this genus. It is the British botanist and nurseryman, James Kelway (1816–1899) who is credited with initially renaming the plant Gladiolus murielae. James Kelway started the Kelways Nursery of Somerset UK in 1851, a nursery that remains in business to this very day. One of his passions was the genus Gladiolus, although the nursery built its reputation on Peonies. After the passing of James, the nursery operation was passed on to his son William and eventually his grandson, who was also named James.

Interestingly, Gladiolus murielae was published in the Gardeners Chronicle in 1932 and it is believed the species epithet honors Muriel Erskine, who was the wife of E.N. Erskine. There is little known of this couple, other than he served as the British Consul or Official in Gore Ethiopia from 1928–1936 and most likely dabbled in collecting plants. I simply find it curious how many of the events leading to the plant's name happened long after 1899 when the founder of the nursery and credited author, James Kelway had died. Perhaps the description and naming of the plant was more of a collaborative process by dad, son and grandson!

Zoom in The floral spike.
Picture 3: The floral spike (bud) emerging from the sheath above.

However, the confusion surrounding the name does not end here! Evidently, the Kelways work remained unknown in botanical circles and in 1973, the South African botanist and plant collector Wessel Marais (1929–2013) once again proposed shifting the genus from Acidanthera, in this case renaming it Gladiolus callianthus, since the species epithet of bicolor was already used to describe another Gladiolus. It was a perfectly appropriate species epithet, since Calli is from the Greek for beautiful and Anthos means flower, translating to Beautiful Flower! However, by botanical decree, the first proper description and name of a plant are the accepted versions, allowing Gladiolus murielae to remain as the recognized name. Oddly, even though Marais's species name was not officially accepted, it is still used by various nurseries, leading to confusion for gardeners looking to purchase the plant. To compound the confusion, often the names are blended, including the name under which I originally learned the plant – Acidanthera bicolor murielae!

Fortunately, the common name is far less confusing! Ethiopia was also known as Abyssinia and the Abyssinian or Ethiopian Empire lasted from 1270–1974. It is also the region where the plant is most prominent, providing the inspiration for the common name.

Zoom in Gladiolus murielae corms.
Picture 4: Newly purchased corms below and 2+ year-old corms above.

Regardless of the challenges concerning the name, Wessel Marais was indeed correct in calling it a beautiful flower! By the time the plants are ready to bloom, the rich green sword-like foliage has grown to 30–40" tall and ¾–1½" wide. The flower stalks are initially concealed in a leafy sheath that stretches well above the foliage. As the sheath opens, the floral spike marked by attractive red, longitudinal lines gracefully drops below the sheath and elongates (as seen in image 3).

Each floral spike produces upwards of 10 flowers which open sequentially from the base to the tip. The flowers are composed of 6 similar sized tepals that constitute the 2–3" diameter white flower with an attractive purple blotch at the center. A tepal looks just like a petal, but refers to flowers whereby the petals and the normally inconspicuous leafy calyx that covers the flower bud look identical. Prominently displayed at the center of the flower are the three, sharply pointed anthers and a slightly longer female style located above the anthers that splits into three, reflexed and lightly bristled stigmas (Picture 2). In addition, the floral tube is exceptionally long and its length allows the flower to slightly droop under the weight of the tepals (Picture 8).

Another common name is Fragrant Gladiolus, highlighting the sweet fragrance the flowers emit at night. The flower shape, evening fragrance and coloration suggests it is pollinated nocturnally by moths, most likely the Sphinx Moth of Africa.

Zoom in Gladiolus murielae corms in pot.
Picture 5: Newly purchased corms in pot on left, 2+ year-old on right.

Although it is often called a 'Bulb', Abyssinian Gladiolus grows from a corm, not a true bulb. Corms are actually a modified stem that appear solid when cut in half, versus a true bulb that is composed of layers of modified leaves, much like an onion. Most retailers sell the plants in packages of 10–20 corms. The newly purchased corms are typically ½–¾" in diameter, as seen in the lower row of corms in Picture 4, and should be planted 3–4" deep. The corms overwintered from previous years are much larger, measuring 1–1 ½" in diameter and are the upper row of corms in the image. These larger corms should be planted 4–6" deep. The differences between newly purchased and overwintered corms extends beyond just the size of the corm. When planted in late May, the newly purchased corms push new, sword-like growth rapidly with the tips appearing within a week! Corms that are overwintered are more leisurely to appear, not showing new growth for 2–3(4) weeks. Although more leisurely, the older and larger corms produce more floral stems and grow taller, making the effort of digging and overwintering them worthwhile. In Picture 5, the pot on the right display's plants grown from the older, overwintered corms while the pot on the left display's plants grown from newly purchased corms. Both were planted at the same time and obviously, the pot of newly purchased corms on the left were also the first to bloom!

I would also suggest not planting the corms all at once, but to stagger the planting over a three-to-four-week period. The plants bloom roughly 8–10 weeks following emergence and the staggered planting will provide the garden with a longer appearance of the blooms. As seen in the image from Wave Hill (Picture 6), planting 10 or more corms together provides a far more effective display than planting them individually or in rows.

Zoom in Plants at Wave Hill.
Picture 6: A massing of plants at Wave Hill.

In their native regions of growth, the corms grow in well-drained soils on rocky outcrops in full sun. In the garden, they prosper best in full sun and make great additions for container culture or for planting in the ground and pairing with white variegated or purple foliage plants, repeating the colors of the flower. For containers, make certain the soil remains moist and does not become excessively dry.

In zone 7 or colder regions, dig and dry the corms following the first killing frost. Interestingly, the original corm only lasts one year and when the plants are dug, a newly generated corm will appear on top of the original. By late fall, the original corm is a dried skeleton of its former self (as seen in Picture 7) and can be easily dislodged from the base of the new corm. In addition, a number of small cormels or baby corms appear around the new larger corm and typically will not bloom for two years. The corms, especially the small cormels that can easily dehydrate, should be stored throughout the winter in perlite or vermiculite to retain their moisture. If the humidity is higher such as in a lightly heated garage, the larger corms can be hung in onion bags with temperatures sustained between 40 and 60 degrees.

Zoom in Newly grown corm and cormel.
Picture 7: Newly grown corm and cormel atop the original corm.

Like all Gladiolus, this species makes a wonderful cut flower and unlike most Gladiolus cultivars, its more relaxed form allows it to blend better with other plants in garden settings. I have heard some people complain over the plant failing to flower, but I have never had an issue in the 35+ years of growing this plant providing the plant is not subjected to droughty conditions. Although confusion remains surrounding its botanical name, for those who have come to discover and appreciate this plant, I suspect they would agree with Wessel Marais in calling Abyssinian Gladiolus a Beautiful Flower!

Gladiolus murielae in August.
Picture 8: The long red floral tube and flower.