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Gladiolus (Gardens Illustrated)


At last year’s Gardens Illustrated lecture, nurserywoman Beth Chatto brandished aloft a Gladiolus. For a moment her gesture reminded me of Dame Edna Everage – but Mrs Chatto’s elegant flower was as different from Dame Edna’s overblown blooms as the two women are from each other. While the antipodean drag queen showers her audience with gaudy, puffed-up hybrid ‘gladies’, Mrs Chatto sings the praises of the delicate ‘species’ gladioli – the wild version of this plant.

A preference for growing species plants conjures a geeky subculture. Beth Chatto has spent a lifetime moving species plants out of this ghetto and into our gardens by demonstrating that their simplicity makes them as much at ease in the garden as they are in the wild. This is clearly seen in the Gladiolus genus: trussed-up hybrids with bright, blousy flowers that are difficult to place in the garden, against enchanting small-flowered species that combine effortlessly with other plants.

The gladiolus Mrs Chatto waved about was G. tristis, whose pale-cream flowers have a green hue and are sweetly scented, especially at night. In Britain the plant is only hardy in very well-drained soils but it is easy to grow in large pots that are kept well-watered during the spring and stored in the greenhouse over winter.

G. tristis is one of 250 species of gladioli that originate in sub-Saharan Africa, mainly in southern Africa. The majority grow in rich, well-drained soils in sunny locations. On most plants the flowers grow on one side of the stem and the individual flowers are perfectly symmetrical: zygomorphic, a botanist would say.

The plant grows from a corm, formed from the swollen base of the stem. Each year a new corms, known as cormlets, grow around the base. So numerous are these cormlets that some species can form large colonies. The magenta flowers of G communis subsb byzantinus that look so beautiful carpeting meadows in their native Mediterranean have become a thug in mild, dry areas. The true form is an invigorating, strong magenta colour, but you see lots of wishy-washy pink impostors for sale. Planted in drifts in the border or dotted through long grass the true form is energetic and exciting; the pale imitations merely dull.

In milder areas of the country G papilio also has a reputation for being an invasive thug. The flowers are more bell-shaped than most gladioli: greenish-yellow pixie hats suffused with a purple wash. G. callianthus is much more difficult to bring through the winter – fortunately the corms are inexpensive, so I buy new ones each year. It doesn’t flower until September and despite its 1m tall stems doesn’t need staking. The bright white flowers have a plum central zone and smell of cloves and spices. G. callianthus has gone through several name changes and you may still find it being sold under one of its former names of Acidanthera bicolor.
The most unusual colour in species gladioli is the dark violet-blue of G. atroviolaceus. It is only 30cm high but the stem is full of flowers. In mild areas it will overwinter, but the rest of us will need to lift the corms and store them in a frost-free place.
 
Most gladioli thrive in full sun and well-drained soil but G. cardinalis needs some shade and a moist soil. In its native South Africa it is known as the waterfall gladiolus, after its preferred habitat. It is a hardy species with, as its name suggests, cardinal-red flowers. This species has been crossed with G tristis to produce G x colvillei, which has the robustness of cardinalis and the delicate flowers of tristis – although the scent has disappeared in the crossing.
There are two white forms of G x colvillei: ‘The Bride’ and ‘Albus’. Both are hardy in a well-drained soil and form large clumps about 45cm tall with flowers during June and July. ‘Albus’ is the brighter white of the two but does have a yellow stripe on the lower petals.

Appreciating species gladioli doesn’t mean that we have to exclude the hybrids and cultivars. There are more than 10,000 of them, so there are bound to be a few that are appealing. The genus is so large that it is sub-subdivided into several categories, the three main ones being Nanus, Primulinus and Grandiflorus.
 
The Nanus group has two or three slender flower spikes about 30cm tall in early summer. It has a loose habit and the stems tend to bow forward. Most of the Nanus group cultivars have red, pink or white flowers. On the white-flowered G. ‘Prins Claus’, the three lower petals have the lipstick stain of a kiss from Dali’s Mae West. G. ‘Nymph’ is similar, with just the outline of the lips.

Flowering into late summer, the Primulinus group has self-supporting stems up to 75cm tall with about 20 flowers on each stem. They are not hardy and need to be lifted during the winter. Bred in the late 1940s and very popular since,  G. ‘Atom’ has pillar-box red flowers with each petal edged in silvery-grey. Primulinus are available in the wide range of colours associated with gladioli: ‘Lady Eleanor’ is pale orange, ‘Ivanhoe’ soft pink and ‘Mrs M Rowley’ burgundy-red. Several gladiolus breeders have finally cottoned-on to the idea that the Primulinus group are great garden plants. Look out for new cultivars over the next few years.
The Snoek family, based in Flevoland in the Netherlands, have been breeding gladioli for the show-bench and the garden for decades. G. ‘Flevo Jive’ has ruffled yellow petals and flowers in early summer. I grow it through the dark-blue flowers of Anchusa ‘Loddon Royalist’. The strong stems of the Anchusa help support the gladiolus. Lime green and purple on the same flower may sound an unlikely combination but looks gorgeous on G. ‘Flevo Cosmic’. Not a plant for the faint-hearted, it’s become my favourite gladiolus.

As for those big and blowsy Grandiflorus plants, try growing them in large pots, although they will still need staking. If you want them for cutting, best grow them in rows in the vegetable garden as the French do. Getrude Jeykll wrote that they could be grown in ribbons through the border. This works well with G. callianthus but I can’t imagine what varieties Miss Jekyll used or how she supported them. One of the biggest plant breeders at the time she was writing was Victor Lemoine in France. He was proud to have produced gladioli with individual flowers six inches wide: probably not the sort of plant that would be popular today. Most of his overblown introductions have disappeared; the delicate G. tristis advocated by Mrs Chatto is still growing strong.