The gladioli made so popular by Dame Edna has been a highly treasured flower for many centuries. The plant gets it’s name from the old Latin word “gladius” which was the Roman word for the swords used by gladiators.
Indeed the leaves and even the flower spikes do resemble a gladiators weapon. Most of the 180 known species are native to South Africa and the Mediterranean. These include most of the smaller, often butterfly-shaped blooms on thin spikes gracefully held above grassy foliage.
Many of the larger types are natives of Europe and the Middle east. This is where our modern-day florist hybrids have come from. There are today thousands of named cultivar hybrids in every shade of the rainbow.
These gladioli are respected as one of the world’s best cut flowers. They are divided into four main groups: Dwarf (nanus) grow no taller than 60cm (24 in.) with delicate flowers of every possible colour.
These are superior for floristry and as a container plant. Slightly larger Primulinus gladioli were only introduced into cultivation around 1900. Discovered on the Zambesi River, these were called the “maids of the mist” because these Renoir pastel blooms have a hooded upper petal to protect them from the misty falls where they were found.
Butterfly gladioli are ruffled with trailing sections that resemble a butterfly in flight. Many have distinctive contrasting blotches on the throat. The large flowering hybrids have flowers 250mm (5 in.) flowers with 13 or more blooms per spike.
The formal types have opposite facing blooms with overlapping petals that hide the stem. Informal varieties have staggered blooms. All are very easy to grow. The species varieties are best planted in autumn for late winter through late spring blooms.
The hybrids are best planted now and throughout the spring. Choose a warm, sunny site sheltered from winds. While the corms will grow in many soils they prefer ones that are deeply rich, and a loose loam that drains well but always holds a bit of moisture.
Avoid freshly manured soil and all acid soils. Plant the corms with the small green shoot facing upward 125m-l5Omm (5-6in) deep and 6in apart. Plant a little deeper in sandy soils. In heavy soil place a handful of sand beneath the corm to stop rotting. Gladioli corms will rot if waterlogged. For giant show blooms give more space between each corm. The blooms are very top heavy so will usually need staking.
This is often best done when the bulbs are planted. While they are classically planted in rows 60cm apart they can be planted in clumps, blocks or large beds which can make the supportive staking easier. Some gardeners dip their corms before planting to kill any eggs of thrip, mite or aphid and for fungus. At the early stages of growth, water gladioli sparingly, and only if conditions become dry. It is better to cultivate the soil around them rather than to water.
At the third leaf stage spray for thrip which, if unchecked will turn the blooms into dried knots. Increase the watering by leaf four and feed with a complete plant food. A balanced food for gladioli would consist of 4 parts superphosphate, three parts blood and bone, and two parts sulphate of potash. Scratch this into the soil but avoid letting it drift against the shoot or corm or burning will result.
For biggest show blooms also feed with liquid manure at the first signs of a flowering spike and continue until the first colour appears. Flowers appear 90 to 110 days from planting. Cut stems on a slant when the first bloom is just opening and recut the stem every second day to make all the blooms open right up the stem. Do not remove the foliage as this will damage the development of next year’s corm.
Those left in the garden should have their faded blooms removed before they can go to seed ( unless the bloom is raised for hybrid seeding). Let the foliage ripen for up to 6 weeks or until it begins to turn yellow. Cut it off and dig the corms then. Let them air dry as quickly as possible. Check any suspicious ones for rot, storing only the best in mesh bags in a dry, airy shed ready for replanting next year.