High summer in the Carpinteria Garden Park is a riot of color and fragrance. Orange squash blossoms bigger than your hand peak out from the foliage of climbing scarlet runner beans with brilliant white and red flowers. Head-high sunflowers twist in the breeze and multi-colored zinnias bloom vigorously, welcome weeds from our homemade compost. Tomato flowers are much more discrete: you have to look closely to spot the small, yellow blooms hidden in the vines. In the wild edges of the garden, landscaped primarily with native plants, fragrant California wild rose is covered in delicate pink flowers and brilliant red rose hips, an important food for many birds and small animals.
Everywhere is the low, steady hum of happy insects crawling over the flowers of fruit trees, vegetables, herbs, and native plants, providing their essential service of pollination. Pollination is mostly performed by insects, including butterflies, night-flying moths, bees, and wasps. Bats and birds are also adept pollinators, able to fit into larger and more open-faced flowers. On the North American continent alone, there are more than 4,000 species of native bees who pollinate both agricultural and wild ecosystems.
Pollinators have found the garden of their own accord. Monarch butterflies are attracted to their primary food plant, the native narrowleaf milkweed. Bumble bees visit native plant species such as white sage, sacred datura, grindelia and goldenrod. The community garden is also home to four European honeybee hives cared for by a dedicated garden member.
Pollination is essential to the existence of our species, since pollinated flowers become the fruits, vegetables, nuts and seeds that are the root of a healthy diet. According to the Food and Agriculture Organization of the United Nations, three out of every four food crops (including 87 of the leading food crops worldwide) rely on pollination to produce the food we eat.
Floral evolution has designed myriad tools to lure pollinators in for the essential business of fertilization: intoxicating fragrance, bright colors and even ultraviolet markings invisible to the human eye that visually signal bees. These complex, reciprocal relationships developed over tens of thousands of years. Some plants can only be pollinated by one species of insect, while others are much more flexible. Many insect species will spend their entire life cycle—from egg to instar to breeding adult—on one plant species, while more cosmopolitan insects find food and shelter wherever they range. Regardless, the relationships between insects and plants are essential for the survival of entire ecosystems, as well as our own food supply.
These relationships are more threatened than ever before. Human-caused climate disruption and habitat loss are incredibly damaging to the nuanced co-evolution of plants and pollinators. Another major disruption is the overuse of poisons by homeowners and industrial (non-organic) agriculture. Insecticides and pesticides kill beneficial invertebrates indiscriminately. One of the most problematic is a class of agricultural chemical called neonicotinoids, systemic pesticides that infuse plants from roots to pollen with poison that kills any pollinator that comes in contact with the plant, as well as soil invertebrates such as earthworms. Herbicides such as glyphosate (sold as Roundup at garden and hardware stores) kill the flowering plants pollinators rely on for food. New peer-reviewed research published in 2019 highlights that more than 40 percent of insect species are declining, with over one-third endangered.
Since humans rely so strongly upon pollinator services for the food we eat and the natural ecosystems we love, these statistics are deeply troubling. A lot has to change quickly in order to reverse these steep declines, and it is essential that we do so, both for our own survival and for the sake of the other-than-human world.
Consider supplementing your landscape with native plants, which bloom year-round with limited irrigation and are an essential food for native pollinators. Limit your use of household chemicals and support gardening and farming practices that do as well with your patronage at the grocery store or farmers’ market. Leave corners of your garden messy—lots of insects, including native bees and moths, prefer to lay eggs and overwinter in dark and protected places with leaf litter and dry wood. While there are many native bee homes on the market, you can do just as well with a stacked wood pile and some bare dirt for bees that prefer to dig underground homes in exposed soil.
One of my favorite resources to learn more about the vast world of invertebrates and how to support their well-being is the Xerces Society, a non-profit dedicated to invertebrate conservation with many incredible resources freely available on their website, xerces.org.