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There are few people who are not familiar with the name gladiolus. Even in the dictionary, the name can be found, not only as a 'cormous plant with sword-shaped leaves and vividly colored flowers', but also as an insult. No flower has achieved such notoriety.
The death or the gladioli
The name gladiolus is derived from the Latin word 'gladius', which means sword. In ancient Rome, gladiator fights were held. If a gladiator lost, he was dead, and if he won, he was buried under the gladioli. However, unfortunately, there is no evidence linking the gladiolus to gladiator fights, even though the plant was known at that time.
It could also have originated from cycling jargon, where one can either fail or be overwhelmed with fame (a bouquet of gladioli for the winner). So, it means: all or nothing, do or die.
The gladiolus that was named 'Vierdaagse' in 1983 was replaced in 2016 on the occasion of the 100th Vierdaagse by the new gladiolus 'The Walk of the World'. Why? The 'old' gladiolus was so heavy that a bunch of them was almost impossible to carry after four days of walking. The new gladiolus is shorter and lighter than its predecessor.
Large-flowered Gladioli
The first large-flowered gladiolus, Gladiolus x gandavensis, was a cross between Gladiolus cardinalis and Gladiolus psittacinus. It was bred in 1837 by H. Bedinghaus, the gardener of the Duke of Aremberg in Enghien, near Ghent. This gladiolus was first introduced to the market in 1841 by L. van Houtte from Ghent.
Around 1900, breeders from England, France, the Netherlands, Germany, and America had already made many crosses, resulting in more than 10,000 cultivars available in the most beautiful colors and combinations. However, not all of these 10,000 cultivars are still cultivated, perhaps only a few hundred.
But the wonderful thing is that breeders still work on creating newer and even more beautiful cultivars that fit the current trend. Flowers, like everything else, are subject to fashion trends, and breeders must have foresight because it takes at least ten years before they can introduce a new cultivar to the market.
Sun and Warmth
Gladioli originally come from South Africa, but you won't find our garden gladioli anywhere in Africa. Nevertheless, they are still closely related to their ancestors and require sun and warmth.
With the exception of most small-flowered gladioli, they are not winter-hardy in our climate. Plant the bulbs in April-May when no more frost is expected, in a sunny, sheltered spot.
They also require well-draining soil and dislike wet feet. If there is little rainfall, you can occasionally water them. Give the plants a handful of organic fertilizer once they start blooming, but don't overdo it.
This is especially useful in poor sandy soil; they don't need anything extra in clay soil.
With the exception of most small-flowered gladioli, they are not winter-hardy in our climate. Plant the bulbs in April-May when no more frost is expected, in a sunny, sheltered spot.
They also require well-draining soil and dislike wet feet. If there is little rainfall, you can occasionally water them. Give the plants a handful of organic fertilizer once they start blooming, but don't overdo it.
This is especially useful in poor sandy soil; they don't need anything extra in clay soil.
How a Gladiolus Grows
Gladioli have a stem bulb underground protected by a fibrous coat. The bulb has a clear basal plate from which roots grow. It's helpful to plant the bulb with the right side up (the narrow side).
After planting, the bulb quickly forms roots and spear-shaped shoots. There is no flower spike visible yet (a spike is a flowering structure consisting of a main axis with sessile flowers).
As the bulb develops more roots and the leaves further unfold, a flat green flower spike appears. When the leaves reach their final height, the spike continues to grow, and the individual flower buds along the flower stem become visible.
The lower buds start to change color, and the flowers open from bottom to top over two to three days. Remove the flower stem once all the flowers have wilted.
Tidy gardeners may remove the faded flowers one by one, but this is not necessary. The leaves continue to grow and will produce a new stem bulb on top of the exhausted mother bulb.
After planting, the bulb quickly forms roots and spear-shaped shoots. There is no flower spike visible yet (a spike is a flowering structure consisting of a main axis with sessile flowers).
As the bulb develops more roots and the leaves further unfold, a flat green flower spike appears. When the leaves reach their final height, the spike continues to grow, and the individual flower buds along the flower stem become visible.
The lower buds start to change color, and the flowers open from bottom to top over two to three days. Remove the flower stem once all the flowers have wilted.
Tidy gardeners may remove the faded flowers one by one, but this is not necessary. The leaves continue to grow and will produce a new stem bulb on top of the exhausted mother bulb.
Overwintering – Large-Flowered Gladioli
Do not leave the bulbs of large-flowered gladioli in the ground; instead, dig them up in autumn and let them dry in a warm place. Clean them and store them in a frost-free location in a cardboard box filled with dry peat or sawdust. Small-flowered gladioli can tolerate light frost.
During severe frost, cover them with fleece, straw, or a layer of leaves. Alternatively, if gladioli are in pots, move them to a frost-free location before freezing temperatures arrive. Ensure that the soil in the pots is not too wet from autumn rains. It's better to protect them from heavy rain by placing them under a shelter before the worst of the rain arrives.
During severe frost, cover them with fleece, straw, or a layer of leaves. Alternatively, if gladioli are in pots, move them to a frost-free location before freezing temperatures arrive. Ensure that the soil in the pots is not too wet from autumn rains. It's better to protect them from heavy rain by placing them under a shelter before the worst of the rain arrives.
Large-Flowered and Small-Flowered Gladioli
According to the latest insights, gladioli are divided into two groups, which are also the two groups we adhere to:
- The large-flowered group;
- and the small-flowered group.
Like dahlias and roses, the colors of gladioli are extremely varied. And not only in terms of colors, but there is also an enormous variation in flower shape, flower size, growth habit, and length.
As expected, small-flowered gladioli have smaller flowers, remain shorter, and bloom earlier. They are closest to the wild species. Small-flowered gladioli grow 50-70 cm tall and with some care can overwinter outdoors in the ground.
The very first cross between the small-flowered species Gladiolus cardinalis and Gladiolus tristis, Gladiolus x colvillei, was performed in 1823 by the English farmer James Colville. By crossing these wild species, a cultivar suitable for our European soil was created.
It is remarkable that this white-flowering little gladiolus is still on the market under this name. Flowers of the cultivar Gladiolus x colvillei ‘The Bride’ are often used for bridal bouquets.
Later, more and more crosses between different species were made, resulting in a large number of small-flowered gladioli on the market today. They fit nicely in the border and are also excellent cut flowers. These gladioli are often sold as a mix, a blend of various colors.
It's more appealing to purchase them by name, as you can combine them well with other plants in the garden or in pots. They come in the most beautiful colors and color combinations;
- bright red with a white edge,
- yellow with red,
- salmon pink
- and many more beautiful options.
Small-flowered gladioli is a collective term for all gladioli that are not large-flowered. They are also known in the trade as 'nanuses', baby gladioli, or mini-gladioli.
Gladioli that can still be traced back to a species are labeled with both the cultivar name and the species name.
Gladioli that can still be traced back to a species are labeled with both the cultivar name and the species name.
Cut Flowers
Gladioli can be cut as soon as the bottom bud opens. Place the flowers in a clean vase and regularly top up with water. For very long flower stems, the top bud can be removed as it may not always open. They make impressive cut flowers. A vase full of large-flowered gladioli is hard to miss.
With large-flowered gladioli, you can create the most beautiful bouquets. They have long stems and a double row of flowers. Gladioli are commonly used as funeral flowers and are exported to other countries, such as Russia, especially for this purpose. White and red gladioli are mainly used for this, but gladioli are also appreciated for celebrations and events.
Large-flowered gladioli alone, with their size and imposing appearance, can create enormous flower arrangements that can fill a large space. Small-flowered gladioli can be excellently combined with other summer flowers.
Flowers
Gladioli deliver double the impact. Their flowers are arranged on both sides of the stem, giving the impression of a whole bunch of flowers from just one gladiolus. The flowers are arranged along the flower stem in a spike. A spike is a type of inflorescence consisting of a main axis (flowering stem) with sessile flowers.
Flowers are termed "sessile" when they lack a flower stalk. With gladioli, you're not picking just one flower but an inflorescence that can consist of 20-30 flowers in the case of large-flowered gladioli. Each flower consists of two bracts. The colored sepals and the petals look the same and are therefore called tepals.
The gladioli we know today are the result of 150 years of breeding from a number of wild species. The most beautiful ones were selected from all these crossings.
Huge Diversity
For years, wild gladioli from tropical Africa and southern Africa were considered an unidentifiable nightmare. The plants were so vastly different that many species of gladioli ended up in the wrong family.
With more than 250 species, Gladiolus is one of the larger plant genera in the world. However, in the iris family, Iridaceae, to which gladioli belong, Iris takes the lead with 300 species. But the impressive number of gladiolus species says nothing about the diversity of the plant in terms of growth habit, flower color, and flower shape.
The plants range from 30 cm tall dwarf species from the semi-deserts in western southern Africa to giants over 2 meters tall in the more humid parts of southern Africa.
The diversity of the flowers is so vast that several species were long attributed to other genera.
Abyssinian Gladiolus
The Abyssinian Gladiolus is one of the gladiolus species that was misnamed for a while as Acidanthera murielae. Nowadays, the Abyssinian Gladiolus is recognized as a true gladiolus and is named Gladiolus murielae. This oddball, found in the wild in Ethiopia (formerly Abyssinia), blooms in August-September with fragrant white flowers marked with dark purple.
Place the plant in a pot on the terrace and be delighted by its lovely evening scent. This gladiolus, which doesn't grow taller than 60 cm, should be overwintered indoors with the pot. Once you've discovered this graceful flower with its delightful fragrance, you won't want to be without it. Overwintering in the ground is not successful.
If you decide to remove the bulbs, store them in a warm place or purchase new ones next year—they are beautiful enough to warrant it. The plant was discovered by the English plant explorer Ernest Wilson and named after his daughter, Muriel Wilson. See below for the Gladiolus murielae.
Place the plant in a pot on the terrace and be delighted by its lovely evening scent. This gladiolus, which doesn't grow taller than 60 cm, should be overwintered indoors with the pot. Once you've discovered this graceful flower with its delightful fragrance, you won't want to be without it. Overwintering in the ground is not successful.
If you decide to remove the bulbs, store them in a warm place or purchase new ones next year—they are beautiful enough to warrant it. The plant was discovered by the English plant explorer Ernest Wilson and named after his daughter, Muriel Wilson. See below for the Gladiolus murielae.
A Blessing or a Curse
There are two groups of people in the world of plants.
Group one
One group believes that the gladiolus, cultivated for over two hundred years, represents the greatest contribution from Southern Africa to horticulture worldwide.
Group two
The other group believes that the 150 years of breeding and selecting gladioli have been a great failure, resulting only in large-flowered, long-stemmed, and undoubtedly beautiful plants that bear little resemblance to the wild gladiolus species.
The truth, as usual, lies somewhere in between.
Pollination
Breeders have developed plants that thrive in our climate, apart from the fact that they are (usually) not frost-hardy. If we had only imported the species, they probably would not have been able to survive.
Here's where the pollination story gets really complicated. It turns out that gladiolus species are pollinated by insects or even birds attracted by the sometimes hard-to-reach nectar.
Bees, flies, butterflies, and honeybirds are responsible for pollination in their country of origin. Botanists have discovered the reason why so many different insects are needed to pollinate so many differently built flowers.
Most gladiolus species occur in Southern Africa, where it rains a lot in winter. If, after a cold, wet winter, all the flowers bloom en masse, there may not be enough bees to pollinate that sea of flowers.
That's why the different gladiolus species, each with their own color, shape, and scent, try to attract the attention of the corresponding insects.
And that's why the diversity of the Gladiolus genus is so enormous and why it's possible to create so much variation through breeding.
Here's where the pollination story gets really complicated. It turns out that gladiolus species are pollinated by insects or even birds attracted by the sometimes hard-to-reach nectar.
Bees, flies, butterflies, and honeybirds are responsible for pollination in their country of origin. Botanists have discovered the reason why so many different insects are needed to pollinate so many differently built flowers.
Most gladiolus species occur in Southern Africa, where it rains a lot in winter. If, after a cold, wet winter, all the flowers bloom en masse, there may not be enough bees to pollinate that sea of flowers.
That's why the different gladiolus species, each with their own color, shape, and scent, try to attract the attention of the corresponding insects.
And that's why the diversity of the Gladiolus genus is so enormous and why it's possible to create so much variation through breeding.
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