Biodiversity and decorative value with naturalizing bulbs

Good at re-wilding

Naturalizing bulbs were planted centuries ago on country estates and at castles and country houses. They are known as ‘stinzenbollen’ in the Netherlands – ‘stins’ is Frisian for ‘stone house’. Wealthy residents used to purchase plants from other areas to increase their prestige, and these plants became established over the years. Many spring-flowering bulbs and tubers fall under this plant group. Most of these bulbs will naturalize effortlessly. In fact, they often come back in larger numbers the following year. They reproduce underground via offsets or through lateral growth of their tubers, and above ground through seed. It is often ants that spread the seeds. Some varieties, such as Eranthis hyemalis (winter aconite), can grow into vast flower carpets.

Suitable for landscaping

In early spring, the nectar and pollen from the flowers of naturalizing bulbs form an important food source for insects and the flowers increase the decorative value of the otherwise still barren public greenery. A selection of the naturalizing bulbs that are suitable for landscaping:

Corydalis cava – synonym: C. bulbosa

The nectar is contained in traces of the light purple-red to white flowers. Honey bees and wild bees, including red mason bees, know where to find them.

Height: 1 foot
Flowering period: March-April
Location: shade

Crocus tommasinianus (woodland crocus)

Perfect honey plant, very popular with honeybees, bumblebees and butterflies, including the small tortoiseshell.

Height: 4-6 inches
Flowering period: February-March
Location: full sun


Eranthis hyemalis (winter aconite)

One of the earliest-flowering plant varieties in the year. The yellow flowers attract bumblebees, honeybees and butterflies. This variety is especially interesting for the earth bumblebee, which gets active early on in the year.

Height: 2-6 inches
Flowering period: January-March
Location: full sun/partial shade

Galanthus nivalis (snowdrop)

The white flowers are attractive to honeybees, bumblebees and butterflies, including the peacock butterfly. Currently not used often in public spaces.

Height: 4-6 inches
Flowering period: February-March
Location: full sun/partial shade

Hyacinthoides non-scripta (common bluebell)

Its lightly fragrant, blue flowers attract hoverflies, honey bees and wild bees, including bumblebees and the red-legged furrow bee.

Height: 8-16 inches
Flowering period: April-May
Location: partial shade

Grand color effect

The number of flower bulbs per m2 depends on the application and the desired visual result in the first year. For uniform planting, which will immediately create a flower carpet in year one, the recommendation for Fritillaria meleagris (chess flower) is 100/m2 and for Crocus tommasinianus (woodland crocus) 200/m2. This number is lower for combined planting with perennials, roses or shrubs. Some flower bulb suppliers compose mixtures with naturalizing bulbs. These mixes make it possible to vary with shapes, colors and flowering periods. For example, after an early bloomer such as Galanthus nivalis (snowdrop), Chionodoxa luciliae (glory-of-the-snow), followed by Tulipa sylvestris (forest tulip) and Narcissus poeticus (poet’s daffodil). Naturalizing bulbs in public spaces create impressive effects, especially after several years. After flowering, they make way for other plants.

Practical tips

To ensure abundant flowering in the following year, the leaves of bulbs and tubers must be left to die off completely. This will allow the bulbs to store sufficient reserve nutrients. This requirement must be taken into account when deciding on the mowing time if there are naturalizing bulbs in the grass. It is crucial that the soil is not disturbed. It is therefore recommended to ask citizens not to enter the grounds.

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