Summer-flowering bulbous plants contribute to biodiversity
The flowers of many summer-flowering bulbous plants contain lots of nectar and pollen. They attract bees and butterflies and they play an important part in increasing biodiversity in green outdoor spaces. The long flowering period of summer bulbs is a plus in that sense. Planting time is after the last frost, from late April until late May.
Perfect melliferous plants
A growing number of municipalities and landscapers are taking measures to increase biodiversity in public spaces. Summer bulbs deserve a place in this and provide a varied food supply for insects. The best melliferous plants (species that provide a lot of food for insects in the form of nectar and pollen) are Liatris spicata (lampshade), Crocosmia (previously known as Montbretia), Anemone coronaria (anemone) and Iris hollandica. Gladiolus also fits in this list; the dwarf gladiolus (Gladiolus nanus) and the Abyssinian gladiolus (Gladiolus callianthus) thrive particularly well in landscaping. All summer-flowering bulbous plants mentioned here come into bloom every year. The lesser-known Tigridia (tiger flower) is also a good nursery plant that deserves a place in landscaping. Dahlias with single and semi-double flowers are also popular with bees and butterflies thanks to the large amounts of pollen and nectar they offer. Tigridia and Dahlia are annual summer bulbs; they are removed from the soil after flowering to be replaced by spring-flowering bulbs.
Grass strips, borders and containers or bowls are all suitable for planting summer bulbs. Special planting machines have been developed for grass, whereby the grass is put back again. The advice for planting under grass is around 200 summer bulbs per square meter. The exact number depends on the species. Most summer-flowering bulbs are sun-loving. They demand little from the soil, it just needs to be permeable to moisture. The bulbs can be planted from late April until the end of May in clusters of one species or in mixtures. They also come into their own when combined with perennials and shrubs. Combined with perennials, around 60 summer bulbs per square meter is advised.
Non-stop food supply
The first varieties flower at the end of May, the last until November. As a result, the flowering lines up nicely with that of spring-flowering bulbs. In this way, they provide insects with non-stop food from early spring until autumn. Most butterfly species use nectar as an energy drink as they use up a lot of energy while flying. Female butterflies also use the energy they get from nectar to lay eggs. Honeybees collect nectar to make honey, an important food source for the bee population. At the same time, honeybees also collect pollen from the flowers. This source of proteins, fats and vitamins is intended for the larvae. Wild bees, including bumblebees, use pollen and nectar for their own energy and for feeding their larvae.
- For landscape, special mixes with summer bulbs for bees and butterflies are available on the market. Their flowering is spread over a longer period.
- Large bee hotels are on the rise, to further increase the bee-friendliness of parks, for example.