Best Bulbs for Containers

 

bulbs that grow well in containers

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When most bulbs are bought they already have within them perfectly formed embryo flowers. All the grower needs to do that first year is to bring the embryo out of the neck of the bulb and up to the flowering stage without set-back. To get them to flower again the next year depends to a large extent on how nearly the conditions they are grown under corres­pond to natural garden conditions. If large bulbs such as daffodils, hyacinths and tulips are grown in rather shallow window boxes they are unlikely to put on as good a show in their second year, always assuming that their wants after flowering are supplied. The build-up of the flower for the second year depends on the foliage being retained until such time as it dies down naturally and on the bulb being thoroughly ripened. Bulbs planted in beds in very shady gardens do not usually give of their best in successive years and often cease to bloom adequately even a second year; this is always due to the bulb not receiving enough sunshine to ripen it. The best destination for most of the larger bulbs once they have finished flowering is some country friend’s garden.

Except for tulips, spring-flowering bulbs should be planted as early in autumn as is prac­ticable at the indicated depth. Most bulbs will start to put down roots within a week or two of planting although there may be no sign of growth above ground until February, March or April. Establishing a good root system is essential. The only other needs this side of the flowering stage are adequate water and, with the taller growers, some form of light staking to prevent possible wind damage. The staking is best done with slim canes and garden twine or raffia. Once flowering finishes, carefully lift bulbs and heel them in a sunny, sheltered place or get them to a friend’s garden as soon as possible.

Plants with other types of bulky rootstock, i such as tubers and corms, are included here.

SPRING-FLOWERING BULBS

Anemone [Windflower; Mediterranean]

Two types of hardy perennial anemones are of interest for use in containers; the first is the windflower A. blanda, a low-growing plant (up to 15cm/6in) from Greece which flowers in February and March in shades of pink and blue. The other is A. coronaria (about 23cm/9in), the florist’s flower with poppy-like blooms. Good strains of the latter are De Caen (single) and St Brigid (semi-double). Spring-flowering anemones grow from corms which should be planted about 7.5cm/3in deep in full sun or partial shade. They enjoy rich soil and regular water­ing. Anemones are not very long lived, parti­cularly A. coronaria, but in a sunny place they could flower for two or three successive years and their foliage does not occupy much space so little is lost by leaving them in the container. Increase by division or offsets in late summer.

Crocus [Mediterranean]

The true species of the peren­nial crocus can be very charming and usually flowers in winter and early spring, but the large-flowered garden hybrids, many of Dutch origin, will create the most effect. ‘Dutch Yellow’ is one of the first to flower, followed by varieties in bronze, rich purple, white, blue lavender, self-coloured and striped. They like ordinary well-drained soil and full sun and show to best advantage in-a sunny sheltered spot. Early autumn planting of the small corms is advisable. Propagate by offsets.

Hyacinthus [Hyacinth; Eastern Mediterranean]

Hardy bulbs, most are hybrids of H. orientalis. Medium-sized bulbs will usually produce one good flower spike each about 30cm/1 ft high; the huge bulbs sometimes produce two spikes which are not so large and more prone to wind damage in window boxes. ‘City of Haarlem’, yellow; ‘Jan Bos’, red; ‘L’Innocencc’, white; ‘Pink Pearl’, clear pink; and ‘Bismarck’, clear blue; are all excellent. They love sun and may need staking, if grown too warm; do this in the early stages. May be increased from seeds, but named varieties do not come true.

Muscari

(Grape Hyacinth; Asia Minor/Southern Eu­rope]

The grape hyacinths are hardy, long-lasting spring bulbs with small flask-shaped

flowers in dense spikes and dark green pointed leaves. The leaves usually appear above ground in the autumn, survive the winter without damage and provide a background for the brilliant azure-blue flowers in April. Good species include M. armeniacum up to 25cm/ lOin, and its varieties, ‘Cantab’, pale blue, and ‘Heavenly Blue’, bright blue, and the dwarfer species, M. botryoides, 15-20cm/6-8in with sky-blue flowers. There is also a white variety. All love the sun and are happy in any average well-drained soil. New bulbs should be planted 8cm/3in deep early in the autumn; established clumps should be divided every three years.

Narcissus [Daffodil; Europe, mainly Spain and Portugal]

The hardy garden varieties of daffodils are probably the most widely grown of all bulbs. With their prominent, often scented trumpet flowers they are the most beloved of all spring flowers. There are several thousands of regis­tered narcissi varieties and their number is increasing each year. The strong-growing older varieties are best for containers. The deep yellow ‘Golden Harvest’ and ‘Carlton’ with soft yellow frilled flowers are recommended, as well as the cream-white ‘Mount Hood’, the pure white ‘Glacier’ and ‘Cantatrice’, the white-petalled ‘La Riante’ with orange-red cup, and the jonquil hybrids, scented and with several blooms on each stem. Some of the miniature varieties, such as the tiny yellow N. asturiensis, the hoop petticoats, N. bulbocochi-cum, the cyclamen-like N. cyclamineus and the pendant cream-white N. triatidrusalbus (Angel’s

daffodils grown in containers

Tears) are excellent in small window boxes and trough gardens.They flower from February on. Narcissus are tolerant of a wide variety of soils, kept moist, and are content with either sun and an open situation or semi-shade. Early planting in autumn is beneficial and the bulbs should be set with their tips at least 8cm/3in below the surface of the soil. Propagation is by offsets at the time of lifting.

Tulipa [Tulip; Eastern Europe/Asia Minor]

Tulips are some of the best and hardiest bulbs for con­tainers as they are reasonably happy to be lifted soon after flowering. They were at one time always dried off in the sun after lifting. The early (March and April) singles and doubles (25-30cm/10-12in) are good for window boxes and higher positions as they are practically un­affected by wind. ‘Peach Blossom’, a rosy pink, and ‘Marechal Niel’, a bright canary yellow with an orange flush, are but two doubles. Recommended singles include ‘Brilliant Star’, red, and ‘Van der Neer’, deep mauve. The taller and later cottage and parrot tulips (up to 60cm/2ft) are more suitable for tubs and deep containers. ‘President Hoover’, orange-red, and ‘Mrs John T. Schecpers’, bright yellow, are among the best cottage tulips. The parrot types include the mauve ‘Blue Parrot’ and ‘White Parrot’. For raised beds, some of the dwarf tulip species make a good choice, such as named varieties of T. greigii (23cm/9in), with handsome purple-marked leaves, and T. kaufinanniana, also known as the water-lily tulip. Both flower in April.

Plant 15cm/6in deep in October and Nov­ember in rich soil and in some sun, preferably sheltered from wind. Propagation is by division of the bulbils.

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SUMMER-FLOWERING BULBS

Canna hybrida [Indian Shot; Central and Southern America]

Cannas are half-hardy tuberous plants and must be lifted and stored on the dryish side in peat tor the winter. They make splendid con­tainer plants with their wide leaves, some of which are tinted mahogany-red, and all have large impressive tubular summer and autumn flowers. These range in colour from deep red, through orange (some are orange-speckled red), to the palest yellow. The fleshy rhizomes should be planted, possibly best on their own, in March, April or May in 25cm/10 in or larger pots, setting the strangely shaped tubers 15cm/ 6in deep. Care should be taken over watering until they have made a good root system when they can be watered freely and fed every two weeks. Cannas like the sun but should not be allowed to dry out completely. Dwarf varie­ties like ‘Alberich’, a lovely salmon-pink with dark-green foliage, will not grow over 45cm/ 18in tall, but stronger growing sorts will eventually reach l-1.2m/3-4 ft.

Convallaria [Lily of the Valley; Europe/Asia]

This popular perennial increases readily by spreading rhi­zomes if it is given the right cool and shady conditions. There is only one species, C. majalis, which lifts its graceful arching stems above a pair of deep green leaves in April to display the sweetly scented, pure white and bell-like flowers. Shade and rich moist soil are essential for Lilies of the Valley; plant in early autumn, just covering the crowns with soil.

Dahlia

Some small-growing dahlias are suitable for container gardening; the bigger ones are deep rooting and a problem to grow in compara­tively little soil. They are all half-hardy peren­nials of garden origin. The miniature and dwarf sorts (45-60cm/H-2ft) include the cactus-flowered, pompon, decorative dahlias and those known as Lilliput dahlias (30cm/ 1 ft ) in single colours or with different stripes or shading. Some new hybrids start flowering when surprisingly young and it is claimed that these may be raised from seed sown in a green­house in March, planted out in May and flowered in July. Such plants would need to be particularly well grown and well fed for dah­lias are thirsty and greedy. These plants will put up a continuous show provided that they have their wants supplied and faded flowers removed. The tuberous roots should be lifted 74 after the first frost blackens the foliage. Tubers

can be stored in boxes of peat and used again the following year, but young plants bought annually in May are less trouble.

Fritillaria [Europe/Himalayas]

These hardy bulbous plants can sometimes be difficult; the stately F. itiiperialis (Crown Imperial) is most hand­some, with its cluster of flowers on top of a tall stem. Named varieties embrace shades of yel­low, orange and red. The smaller F. meleagris (Snake’s Head) is more suited to containers, being only about 30cm/1 ft high; each flower stem terminates in a pair of drooping, bell-shaped flowers that are basically white but heavily marked with purple in a chequered pattern. ‘Alba’ is white with green markings. Fritillaria bulbs must be handled with care; never buy any that are bruised or have been left in the open air for long. Plant them fresh in early autumn, about 10cm/4in deep, and in a good sandy loam, in sun or light shade. Propagate by seeds or by offsets.

Galtonia candicans [Summer Hyacinth; South Africa]

This rela­tive of the hyacinth from South Africa is easily obtained, is cheap to buy and simple to grow. It is best planted in a sunny position, burying the bulb at least 15cm/6in deep whenever prac­ticable. Soon after planting, the bulb will send up strap-shaped blue-green leaves and a tall (to 1.2m/4ft) flowering stem which is capped with a loose raceme of large drooping white bells. There is often a suggestion of green colour in the flowers. These should open around August/ September. Bulbs should not be allowed to dry out and should be left undisturbed. Propaga­tion is by offsets, but these are not frequently produced.

Gladiolus [South Africa/Eastern Mediterranean]

Most people think only of the large-flowered hy­brids of gladiolus but there are a number of attractive species of these half-hardy perennials. The best is G. byzantinus (60cm/2ft) from Asia Minor which is fully hardy. The flower colour is a very strong magenta-crimson and blooms appear early in June. This corm when happy in a sunny position and well-drained soil, will spread freely and should not be disturbed.

The popular gladiolus hybrids include the large flowered butterfly, primulinus and minia­ture groups, the latter two being suitable for large containers. The primulinus and minia­ture hybrids have a wide colour range, often with contrasting centres, available in normal forms or in mixtures. The miniature ‘Bo Peep’, like most others in this group, has frilled flowers.

Corms are normally planted in April, about 10cm/4in deep, in a sunny position. In windy situations it is advisable to stake the corms when planting; this not only eventually pro­vides support for the comparatively large flower spike but also marks the planting posi­tion until growth appears. Some bonemeal applied at the time of planting will help to provide good flower spikes and it is important to see that the corms do not dry out com­pletely. After flowering the corms should be lifted (about November), dried off and the new corm (situated above the old^ separated from the old. The new corms should be stored dry until the following spring.

Gladiolus for container growing

up with new soil once the growth has emerged above soil level. They should be watered only moderately until growth is well established and can be allowed almost to dry out before re-watering during the growing season. Some winter protection from excess rain may be necessary. The oriental lilies are very exo­tic, with large bowl-shaped deeply-fragrant flowers, and happily there are many bulbs of various colours from which to choose. L. auratum, the golden-rayed lily of Japan, and the oriental hybrids as they are called, deve­loped from crosses made between L. auratum and L. speciosum. A cool greenhouse is very helpful to start them into growth.

L. regale from Western China makes a fine show when grown in tubs. It carries huge white trumpet-shaped scented flowers with light purple markings on the outside of the petals. A well-grown clump will certainly reach 1.2m/ 4ft high in July when the blooms begin open­ing. Whenever possible they should be planted about 20cm/8in deep. A layer of coarse sand

Iris [Northern Hemisphere]

This large genus in­cludes rhizomatous and bulbous species, the latter being most suitable for container garden­ing. The most popular are the hybrids which fall into three groups – the Dutch, Spanish and English. The Dutch irises (38-60cm/15-24in) flower first in May and June, follow <^d by the Spanish (30-45cm/12-18in) and lastly the English (30-60cm/l-2ft) in July. All come in a variety of colours, except the English which have no yellow forms. The English irises have the largest flowers, 13cm/5in wide, and the Spanish the smallest (9cm/32in). All should be planted in October, 10-15cm/4-6in deep, in full sun and light soil for the Dutch and Spanish types. These should be lifted after flowering for the bulbs to dry off before replanting in October. The English irises do not need lifting, and they do best in a richer, more moist soil. Propagation is by division.

Lilium [Lily; Europe/Northern Asia/North America]

Many lilies are quite a challenge to grow but a number can be grown very successfully in pots. The pots or tubs must be fairly deep and rich leafy soil mixture should be used. Large containers will enable them to be left un­disturbed for several years, merely being top-dressed with fresh soil. Lilies grown in smaller containers will need repotting each year. All containers should be free-draining. Most lilies used are stem-rooting, i.e. roots are produced on the growing stems; bulbs, therefore, need planting deeply and space should be left at the top of the containers for subsequent topping

growing lilies in containers

just below the bases of the bulbs helps prevent rot. Give plenty of sunshine and plant as soon as received, avoiding specimens that have dried out.

Ranunculus [Far East]

R. asiaticus (up to 30cm/1 ft ) is not
hardy, and the tuberous roots are easily killed
by frost; the plants should be lifted in autumn
and stored for the winter. But their showy
flowers add so much colour to the late spring
scene that they are worth a little extra trouble.
They are usually offered as a mixture of semi-
double flowers in all colour tones from white
to deep red. Plant the tubers, claws down­
wards and 5cm/2in deep, in March and April
after the worst frosts, in sun and shelter and in
fertile soil enriched with peat. Propagation is
by division of the tubers in spring.i*

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crocus grown in containers

AUTUMN-FLOWERING BULBS

The colchicums are beautiful autumn-flower­ing bulbs but unfortunately after their flowers they produce large leaves which turn brown as they fade. They are ideal for growing in short grass where the pastel crocus-like flowers add welcome splashes of colour. Pure white, rose-pink and lilac colours are available from C. autumnale. The genuine autumn crocus (Crocus speciosus and its varieties) from Eastern Europe and Asia Minor are, however, different and are useful for planting under shrubs. Rose, lilac and white forms are available and should be planted about 5cm/2in deep from mid-August when they will flower in September and October. They are best left undisturbed from year to year.

Many other bulbs add welcome autumn colour, such as Amaryllis belladonna (syn. Hip-peastrum equestre). The huge, trumpet-shaped flowers appear on naked stems in autumn, usually pale pink and sweetly fragrant, but there is also a pure white and a deeper pink form. They are half-hardy, and need some protection against wind and frost. Pot the bulbs in pots, 15-20cm/6-8in deep, in June, using a good, well-drained soil. Set the plants in a sunny, sheltered position. Propagation is by division after the leaves die down in summer.

Nerine bowdenii from South Africa is hardier than generally assumed and will flower for years at the foot of a south-facing wall. The delicate large flower heads are composed o( small pink flowers on leafless 60cm/2ft high stems through the autumn. Plant the bulbs 10cm/4in deep in April or summer, in any type of good soil, preferably in full sun. Leave un­disturbed for several years, then lift, divide and replant.

Sternbergia lutea (20cm/8in) has yellow crocus-like flowers in October, but unlike crocus the grass-like leaves appear at the same time as the flowers. Plant the hardy bulbs 15cm/6in deep in ordinary soil and full sun. Leave alone until the clumps become crowded, then lift, divide and replant.

Another cheerful little autumn-flowering bulb is the snowflake, Leucojum autumnale, whose white drooping flowers resemble snow­drops although the petals are shorter and more rounded and usually have a pink flush. Grow in sun and well-drained soil, setting the bulbs 5cm/2in deep in early summer. Propagation is by division.

WINTER-FLOWERING BULBS

Early crocus species, such as C. ancyriensis ‘Golden Bunch’, appear in February, at the same time as the attractive bronze-coloured C. chrysanthus and the white, pointed C. biflorus, several weeks before the more popular and large-flowered hybrids. The attractive little winter aconite, Eranthis hyemalis, appears now too. It seldom reaches more than 10cm/4in in height, and the small, bright yellow flowers surrounded by a frill of pale green, deeply divided leaves, poke their heads up over snow and frost. The small tubers should be planted as soon as available in early autumn, 3cm/lin deep, in well-drained moist soil, preferably loamy. They do very well in light shade and associate marvellously with snowdrops. Lack of water during the spring season may curtail flowering the following year unless the soil can be kept moist.

The dwarf bulbous irises, such as I. dan-fordiae, bright yellow, /. histrioides major, blue, and /. reticulata, scented and almost purple-blue, are perfect winter-flowering plants for raised beds and pans, in sheltered positions. They are perfectly hardy.

Chionodoxa lucilae [Glory of the Snow; Crete and Turkey]

These small blue and white star-shaped flowers are often evident after snow has melted, hence the common name. These hardy bulbous peren­nials (15-20cm/6-8in) are exceptionally easy to grow and will last for years – where they are completely happy they will multiply annually. The small bulbs should be planted 5-7.5cm/ 2-3in deep in early autumn. Pink and white forms are available but may take some tracking down. Propagate by seeds in spring.

Cyclamen neapolitanum [Italy/Greece]

These are perfectly hardy minia­ture perennial cyclamens with small rose-pink or mauve flowers blotched with a deep crim-

son eye. They flower when leafless from September to November and the corms, which should be planted as soon as they are received, should be only half buried. The attractive leaves, which persist until the spring, are deep green with silvery markings. They must be planted in good leafy loam and left undisturbed for years if sheltered from wind and sun. One route to success is to plant them in rather deep clay pans on their own. The tubers should be set with the slight indentation on top as it is from that surface that the roots emerge.

Galanthus [ Snowdrop; Europe]

The hardy bulbs of single and double flowered snowdrops may be planted in September or October about 5-8cm/ 2-3in deep. Ideally they should only be moved immediately after they have flowered when in full leaf but to do so, for instance, to a window box would be a little unsightly. Dry bulbs do, however, flower even if they take some time to become established. They do not demand sun and show their pure white drooping flowers as early as January.

Scilla sibirica ‘Spring Beauty’ [Squil; Siberia]

These scillas are an enchanting blue and are so cheap to buy and so easy to cater for. The hardy bulbs are happy in either sun or partial shade and will seed themselves freely. They show flower colour – an intense blue – within a day or two of coming through the soil and open up fully from February onwards. Plant 8cm/3in deep.

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