White Flowers and Pollinators

It is a diverse group of agents involved in the pollination of flowers, and not limited to honey bees. Different animal pollinators prefer different types of flowers. Understanding the relationship between flowers and their pollinators is very useful to manage endangered species, to encourage propagation of horticultural plants and to determine the type of garden that satisfy the pollinators one hopes to attract.

In general, pollinators are attracted to plants that offer an abundant reward such as pollen and/or nectar. Early spring wildflowers in the forests collectively tend to be white. Why might that be?

Spring flowering plants, especially the earlier ones, have a small suite of potential insect visitors. They tend to share characteristics in shape and colour. Often the flowers are broad and bowl-shaped and may be visited by up to 20 different pollinators. Those with specialized shapes, such as Dutchman’s-breeches (Dicentra cucullaria) tend to have specialized pollinators. They also tend to grow in masses or colonies.

One explanation for the numerous white species has to do with visibility against the ground for those growing in forests. There are fewer foraging insect species, sometimes the neon advertising method works! Some “white flowers” also produce other pigments visible only under UV lights. Insects such as bees can see these colours. Colour is only one character that is convergent among April flowers. Most are self-fertile, meaning pollen does not have to be received from a stranger. Shape and nectar-production are also important features.

Odour is another important feature. Flowers with a foul odour such as mountain-ash, attract insects attracted to dung or carrion. In particular, they attract flies. Flowering cherry trees have a sweet perfume, which bees find irresistible. These trees in late April and May literally hum with pollinators.
Many moths are active at night or in low light, so require flowers that are open and providing nectar on cloudy, foggy days or later, into the evening. White flowers with a very strong, sweet scent are easiest for them to locate. Examples of flowers for a moonlight moth garden are honeysuckle, flowering tobacco, and primrose. Generally the moths appear later in the spring, although some of the flowers can be open early.





Claytonia caroliniana. Spring-beauty by Martin Thomas

Dutchman's-breeches, Peter Neily photo


white violet, photo by Ross Hall



Sorbus sp., mountain-ash photo by Martin Thomas