There are spring, autumn and winter-flowering kinds; the first group is by far the most popular and generally useful. All crocuses form corms which need to be planted 3-6cm (1-½ – 2-½in) deep, the winter- and spring-flowering kinds in September but the autumn-flowering kinds in August.
The species, including the many colour forms of Crocus chrysanthus, make good rock-garden plants, but the large-flowered hybrids are usually grown in beds or in short grass, which should not be cut until all the crocus leaves have withered.
Often known as Glory of the Snow, these are charming little bulbs forand for edging borders. They have short sprays of starry blue or blue and white flowers in March and April. Plant 5-7cm (2-3in) deep in good soil and in an open, preferably sunny place and leave undisturbed until overcrowded.
The winter aconites look rather like celandines, with a green ruff around each short-stemmed, golden yellow flower. They will grow in sun or semi-shade and can be in flower by January if the weather is favourable. Plant 4-5cm (1½ – 2in) deep and leave undisturbed until overcrowded.
All thrive in semi-shade in rather moist soil containing plenty of peat or leaf mould. Plant 5cm (2in) deep and leave undisturbed until overcrowded. The leaves of the variety Erythronium dens-canis are attractively mottled.
This is a very big genus containing a lot of unusual-looking plants some of which are quite difficult to grow. One of the most popular is F. meleagris, the snake’s head fritillary, with bell-shaped flowers on slender stems in March-April. They may be all white or chequered white and maroon.
This plant likes fairly rich, moist soil and can be naturalized in grass if it is not cut until all the fritillary leaves have died. Very different in character is F. imperialis, the crown imperial, a big plant with stout stems each bearing in spring a cluster of bell-shaped yellow or reddish-orange flowers. It likes rich well-cultivated soil and is prone to grey mould disease which can be attacked with a fungicide in spring. Cover bulbs of F. meleagris to a depth of 5cm (2in), those of F. imperialis, 8-10cm (3-4in).
These are the snowdrops, in flower during February and early March. The British species, C . nivalis , and the varieties derived from it will all grow in sun or shade and are good woodland plants; but the Mediterranean species, with large flowers and broader leaves, succeed best in full sun.
By far the most popular hyacinths are the large-flowered or Dutch varieties, grown formally, mainly in pots, bowls, window boxes. However, there are other types, called Roman, Cynthella and multi-flowering, which have smaller more loosely formed sprays of bloom — these are better for informal groupings with other spring bulbs in borders and rock gardens.
All hyacinths like fertile, porous soil with plenty of moisture while they are making their growth in spring, but warmth and sunshine to ripen the bulbs in summer. They do not mind being lifted annually but this should not be done until the leaves have withered in June or July. They can be stored until October as they have a fairly long resting period. When planted outdoors, the bulbs should be covered with 6-8cm (2-½ – 3in) of soil, but in pots, bowls and other containers leave the tips of the bulbs to peep through the soil. Make sure that container-grown hyacinths have at least eight weeks in a cool place before they are brought into warmer surroundings, where an average temperature of about 18°C (65°F) is maintained. If you hurry growth unduly at the outset, without the period of relative cold, the flower spikes will be poor.
The bulbous-rooted irises include some small, very early-flowering species such as light blue Iris histrioides, violet-purple Iris reticulata and yellow ris. danfordiae, and also the much taller, May- to June-flowering hybrids known as Spanish, English and Dutch irises. The first group are plants for rock gardens, raised rock beds and pots in an unheated greenhouse, the second are good border plants and cut flowers. All like porous, fertile soils and sunny places and need only be disturbed when overcrowded.
The snowflakes, which look a little like snowdrops though some, such as Leucojum aestivum which flowers in April and May, are much taller. They will grow in sunny or lightly shaded places and can be left undisturbed for years.
The grape hyacinths, with small spikes of blue or white flowers, do look rather like tiny hyacinths. They are easy, fast-spreading bulbs excellent for carpeting beneath deciduous trees or for growing in rock gardens and at the front of flower borders. All can be left undisturbed for years and will spread by self-sown. Muscari comosum plumosum is a larger plant with sprawling plumy spikes of violet-blue flowers. All flower in spring.
This is the botanical name for theand they have become one of the most highly developed of all the hardy bulbs. With the exception of some very early multi-flowered varieties such as ‘Scilly White’ and ‘Soleil d’Or’, they are all completely hardy. There are a number of different species ranging from very small plants, such as Narcissus bulbocodium and N. cyclamineus, to much larger ones, such as N. pseudo-narcissus and N. poeticus, but it is the innumerable hybrids between the species which have made daffodils such valuable plants both for gardens and as cut flowers. The flowering season is from January until May with the peak in April. They are among the best bulbs for naturalizing, especially some of the vigorous trumpet and large-cupped varieties.
Daffodil bulbs are best planted in August or September and should be covered with 5-6cm (2-24in) of soil and left undisturbed until they show signs of becoming overcrowded.
Most bulb growers include the bluebells as well as the small squills under this name, but botanists separate the bluebells in another genus called Endymion. The popular squills, such as Scilla sibirica and S. tubergeniana, are all small plants with starry blue flowers in spring, excellent for carpeting in the same way as muscari. The common bluebell is useful for naturalizing in woodland, but the larger-flowered Spanish bluebell, Scilla ( Endymion) campanulata, is also a good border plant for open or semi-shady places. It carries its bell-shaped blue, pink or white flowers on 30cm (12in) stems in May.
These were the first bulbs really to capture the imagination of gardeners. In general, they have a greater need than daffodils for sunshine, warmth and good drainage, combined with a fairly rich soil that does not become dry during the period of peak growth from March to May. They rest from late June until mid-October and actually seem to derive some benefit from being lifted in July and stored in a dry place at a temperature around 18°C (65°F) until early October when they can be replanted, preferably in fresh, well-cultivated ground.
Alternatively, they can be left undisturbed for many years, especially some of the species, and in some places they can even be naturalized though they lack the vigour and adaptability of daffodils. The greatest use of the large-flowered garden varieties is as spring bedding plants and cut flowers, but some of the smaller-flowered varieties and species are often planted in rock gardens.
Garden varieties ofare classified in groups according to their time of flowering and type of flower. The main groups are early single and early double, both flowering in April; kaufmanniana and greigii hybrids, also April flowering and often confused with one another since they have been interbred; fosteriana hybrids flowering late in April and with very large flowers; the May-flowering Darwin and Lily-flowered, which differ mainly in flower form — the blooms are less rounded in the Darwins and the petals more pointed and reflexed in the Lily-flowered group. There are also smaller classes including one, called multi-flowered, which carries several flowers per stem and another ‘Viridiflora’ which has a partly green flower. Parrot tulips have large flowers in May, usually with twisted or curled petals, and two or more colours curiously streaked and blotched. Late double tulips flower in May and have big double flowers rather like peonies, and Rembrandt tulips resemble the May-flowering varieties except that the colours are ‘broken’, which means that the flower colour, instead of being more or less the same all over, or divided into two or more large and clearly defined zones, is flaked or feathered, sometimes forming beautiful patterns. For several centuries these ‘broken’ flowers were prized by tulip fanciers who were prepared to pay high prices for well-defined or unusual patterns and colourings.