The summer-flowering bulbs such as lilies, gladioli, etc. are lifted in October and November and then delivered to the merchandising chain through the month of January. After having received their temperature treatments, the saleable bulbs will be sent in early spring to the points of sale where consumers will buy them.

Of all the bulbous plants, the lily has shown very considerable growth in terms of hectares cultivated in the last few decades. In 1960, it was being cultivated on just 160 hectares. Now, this figure has risen to 4200! The lily is responsible for 25% of the total export value for bulbs. Its increase in cultivation is primarily due to the new groups of lilies that have been developed for cut flower production. The lily has become a very popular cut flower throughout the world. One of the lily groups, known as the Asiatic Hybrids, offers lilies in orange, red, yellow, white and pink. Also favoured are the Oriental Hybrids with their large white, pink or red scented flowers. Lilies in the Longiflorum Group (including the white ones sometimes known as Easter Lilies) have been grown for a long time, but recent breeding efforts involving the crossing of these lilies with Asiatic Hybrids has produced a new group known as the LA Hybrids. This group is becoming more and more important. In the Netherlands, lily bulb production involves planting the bulbs in the spring and lifting them again before winter. For the production of flowers, the bulbs can be planted throughout the year in many different climate zones, both in the field and in greenhouses.

In terms of the number of hectares used for its production (1700 hectares), the gladiolus is close to the narcissus. The number of hectares has decreased somewhat, mostly due to the great interest in lilies. Traditionally, this very colourful bulbous plant has been used for cut flower production in countries with temperate and warm climates, as well as for planting in gardens. These very tall plants have bright, appealing colours: red, purple, yellow, orange and white. For the production of corms (gladioli are not true bulbs), the growers plant the small corms and cormels in the spring and harvest them in the autumn when they have grown larger.

Like the gladiolus, the dahlia is also known for its bright summer colours. The only colour not included in its spectrum is blue. Its array of shapes is extensive as is suggested by the names of the various dahlia groups: pompon, decorative, collar, anemone-flowering, cactus, etc. Of all the bulbous plants, the dahlia has the longest flowering period of all: several months. Of the more than 450 hectares planted, most of the tubers find their way to gardens and parks. A small percentage is grown for cut flower production. Growers plant cuttings in the spring and harvest saleable tubers in the autumn.

The special bulbous plants are included in both the spring-flowering and summer-flowering groups. This "miscellaneous" group of "other" bulbous plants just might be the most interesting, however. There are dozens (and maybe even hundreds) of them. The number of hectares used to cultivate them is about 500. Familiar representatives in this group are the Grape hyacinths, Fritillaria, Allium (ornamental onion), Anemone, Hippeastrum (amaryllis), Begonia, Scilla, Canna and Zantedeschia (Calla lily). They are planted in gardens and parks, sold in pots, or used as material for cut flower production. Sometimes, a bulbous plant from this group emerges as a major bulbous plant due to its popularity. This happened with the lily and may also occur again with zantedeschias. The interest in this "trendy flower" is so great that it is being grown on much more land every year.