Gladioli and summer and autumn bulbs FAQs

Are there any hardy gladioli?

It is possible to kill most gladioli but some will persist even after hard winters. We have a planting of ‘Green Woodpecker’ that has been left down for eight years and is still on parade. Undoubtedly, however, the plants would have increased better if we had lifted them.

There are some species that usually flourish with good drainage and sun. G. byzantinus can be relied on to produce 600 mm (24 in) spikes of rich purple-red flowers of good size. G. communis is a somewhat taller species; its small corms produce mauve-pink flowers in June on spikes up to 63-75 mm (2Vand-3 in) long.

What is the best way of storing gladioli over winter?

Lift them after flowering provided they can be kept frost-free until planting time. The plants, with their spawn of cormlets, need lifting and then taking to an airy place to dry completely. The tops must be cut away and all soil removed.

The winter dangers are frost, wet, and rot. Ideally the soil-free corms should be rinsed in a fungicide solution, dried, carefully labelled, and stored in trays or plastic net bags in a well-ventilated, frost-proof, dry place. Remember to label each corm, or group of corms, with its name.

My garden is inclined to be windy. Do all my gladioli have to be staked?

The large gladioli often need staking: when the flowers open they offer plenty of sail for the wind to catch. There are, however, races of smaller types that can manage without scaffolding. The Butterfly types are about half to two-thirds the size of their large relatives; they form rather triangular, sturdy flowers into stiff, upright spikes. The Primulinus types are more rounded and informal in shape. The Gladiolus nanus varieties are smaller still, sprightly and altogether pleasing. G. byzantinus, with maroon-coloured flowers, is fully hardy and can be left down year after year.

I have bought miniature gladioli from the florists. Can I grow them myself?

Probably these are Gladiolus nanus varieties; typical are ‘Nymph’ (snow-white with crimson markings), ‘Guernsey Glory’ (pinky orange), and ‘Amanda Many’ (bright salmon with violet-painted flakes). All these are a quarter to a third the size of the big gladioli. They are usually sold in the autumn and can be grown in a cool greenhouse, where they will bloom in spring before those planted outside. In the garden proper the corms do best in a warm spot in well-drained soil.

I would like to plant Allium, but I notice that some species seem to be rather weedy and tend to pop up all over the place. Can you suggest some less-invasive kinds?

I have already mentioned the fine Allium albopilosum and A. aflatunense ; you might also like A. giganteum, one of the largest and tallest alliums, with great violet umbels hoisted up 1.2 m (4 ft) or more in July. Earlier, and half the height, is A. neapolitanum (syn. A. cowanii) with umbels of white flowers. A. karataviense is particularly suitable. It has broad, dark, metallic leaves with a purple-reddish cast especially near the margins. These form a rosette below a 150-200 mm (6-8 in) stem carrying a large globe of white stars, flushed pinky violet, in the second half of May into June.

I have been given some big bulbs labelled Galtonia. Can you tell me something about the plants?

Galtonia candicans (sometimes incorrectly called Hyacinthus candicans) is commonly known as the summer hyacinth. It has a strong bulb and grows 1 m (3 ¼ ft) or more high. Each spike may carry up to three dozen hanging bells of milky white from July to September, and these look quite imposing against a background of dark foliage.

You should plant your bulbs in March or early April and see that they are covered with 100 mm (4 in) of soil. They do best in a well-drained, sunny position. You will enjoy the scent of the flowers.

A friend has some magnificent border plants which he knows only by the name of foxtail lilies. What are they, and are they easy to grow?

These belong to the genus Eremums, and are hardy herbaceous perennials in which tall spikes of star-shaped flowers arise from a ring of narrow, pointed foliage. Among the best and tallest, are the series known as £. ‘Shelford Hybrids’, whose flowers vary in colour but are often a pleasing soft pinky beige. They can reach 2.75 m (9 ft) and bear hundreds of primrose-sized flowers. E. stenophyllus bungei is the yellow-flowered parent of these hybrids, and reaches 1 m (3VA ft) in height; the other parent, E. olgae, is late-flowering, bears pink blooms, and reaches a height of 1.5 m (5 ft). Other fine examples are the very tall E. elwesii with soft pink flowers (and its white-flowered variety ‘Albus’), and the even taller—up to 3 m (10 ft)—E. robustus with pinky yellow flowers on spikes up to 1.2 m (4 ft) long.

I would welcome suggestions for a few unusual hardy bulbs in our mixed beds. Any ideas?

Here are a few to make the neighbours envious: Foxtail lilies (Eremurus), mentioned above. Quamashes (Camassia) are easy, attractive, late-spring performers. C. cusickii 600 mm (2 ft) tall, has lots of pale blue flowers; C. quamash (syn.C. esculenta) 250 mm (10 in), has spikes of white to deep-blue flowers; C. leichtlinii, 900 mm (3 ft), has white or blue stars; C.I. semiplena, with semi-double creamy flowers on sturdy stems, is especially pleasing. Fritillaria persica ‘Adiyaman’ stands 800-1200 mm (2 ½ -4 ft) in May, with unusual, deep-hanging bells of rich plum-purple. Leucojum aestiuum ‘Gravetye Giant’, 300-500 mm (12-20 in), is the best of the summer snow-flakes, and has wide-hanging white bells in April and May.

Looking through an old British flora I found an attractive plate showing a snake’s-head fritillary. I would like to try growing this plant. It is obviously hardy, but what conditions does it need?

Fritillaria meleagris is a rare native plant, sometimes found in water meadows formerly subject to winter flooding. At one time catalogues listed a dozen or so named kinds of white, pink, and many intermediate shades to deep purple. These show varying amounts of the chequering that gave rise to the common name. Nowadays these plants are most often sold mixed. Their large, square-shouldered bells hang from wiry stems 150 mm (6 in) or so high. They grow well in drained but moist soil.

Just as a challenge, I want to grow the giant lily. Are there any special problems?

This is the extraordinary Cardiocrinum giganteum, a native of Himalayan woodland. The bulbs like soils that are moist, deep, and rich in leaf mould. The nose of the bulbs should be just below the surface. The stems can reach the amazing height of 3.7 m (12 ft). Up to 20 funnel-shaped greeny white lily flowers 150 mm (6 in) long may be arranged on these stems. After flowering the huge bulbs die; they leave behind a few offset bulbs that will take 3-4 years to build up to flowering size. It is wise tq^cover the dormant bulbs with a frost-protection layer of bracken or something similar in winter.

I was surprised to see some nerines flowering in a friend’s border in the autumn. I thought these were exclusively houseplants.

All but one nerine require greenhouse cultivation. The exception is N. bowdenii, a plant that is completely hardy—it will survive all but the most severe winters in the British Isles. The most popular form is ‘Fenwick’s Variety’, which is somewhat larger than the species. The plant produces flower spikes through the bare soil in September and October. The 300-400 mm (12-16 in) stems carry several brilliant pink, wide-open flowers in umbels up to 150 mm (6 in) in diameter which last well. The narrow, strap-like leaves appear soon after the flowers.

The bulbs take a while to establish as they do not like disturbance. They should be planted in April or August in well-drained soil with noses just below the surface. A favourable position would be near a sunny wall to help the bulbs get their vital summer baking. Leave the clumps undisturbed until the bulbs have become thoroughly overcrowded every five years or so; then lift, divide, and replant the clumps.

Have the colchicums any advantages over the autumn species of crocus?

One advantage is the persistence of their corms, which are large and increase steadily. Crocus corms often increase rapidly, but mice and other pests can be a problem. A possible disadvantage of colchicums is their huge leaves in the spring, which look rather a mess when they begin to wither. For garden effect I would suggest the following colchicum hybrids, all of them bred by crossing C. speciosum with other species: ‘Lilac Wonder’, easily the most free of bloom, with clusters of pinky lilac flowers with white stripes in September-October, 150-175 mm (6-7 in); ‘Violet Queen’, the earliest with somewhat chequered white-striped purple flowers in September, 125-150 mm (5-6 in); The Giant’, the largest, with pinky violet flowers, 200-250 mm (8-10 in); ‘Water Lily’, a fine double with lots of strap-shaped violet-mauve petals, 125-150 mm (5-6 in).

Some of my bulbs have become squashy and rotten. A friend has suggested that they have become infested with eelworm. Is he right—and is there any simple cure?

I think your friend is probably correct—which is bad news. The cure for this pest is no simple matter. First of all, any bulbs that are obviously infested must be destroyed without delay. The rest would be given hot-water treatment by a commercial bulb-grower. Eelworm, a microscopic pest, can be killed if the bulbs are immersed in water maintained at a temperature of exactly 44.5°C (112°F) for a period of four hours to enable the heat to penetrate the bulbs completely. It is vital that the water is maintained at precisely that temperature. If it goes one or two degrees higher the bulbs will be killed; if it falls below, the eelworms will survive.

Unless you have the equipment to heat the water to that temperature and maintain it within those fine limits, it would be a waste of time attempting this treatment. In that event, you must destroy (by burning) not only the obviously affected bulbs but all others in the immediate area. Just as important—you should not plant any bulbs in the affected area of soil for a minimum of three years; and take care that you do not move any of that soil to another part of the garden.

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