For the last two seasons, I’ve noticed a pretty green hummingbird; I’ll call him Al (the Allen hummingbird is a common species in northern California), visiting the Douglas Iris patch here at the Sutro Nursery. Well, Al might have been Annie, I couldn’t say for sure since the Anna is very similar and also a species of hummingbird common here.
Either way, I hope both Al and Annie continue to visit again and again. And for good reason: hummingbirds, like other pollinators, are helping us to maintain healthy productive plant communities, provide food that sustains wildlife, and play an essential role in crop production. Of course, Al was probably after the nectar in the flower, but as he sips, he also gets the pollen on himself then transfers the pollen to other flowers he visits. Voila!
The Basics – Pollination is the act of transferring pollen grains from the male anther of a flower to the female stigma of another flower of the same species. This is how plants produce seeds to make new plants. We call animals or insects that transfer pollen from plant to plant, pollinators. These could be birds, insects (e.g., bees, butterflies), or bats. Wind and water are also pollinators.
Nearly all of the world’s seed plants need to be pollinated. Pollination enables flowering plants to reproduce as well as maintain genetic diversity within a population. Pollinators are key to reproducing wild plants, which in turn produce breathable oxygen, help to purify water, and prevent erosion. The water cycle depends on plants to return moisture to the atmosphere, and plants depend on pollinators to help them reproduce. Without pollinators, the earth’s terrestrial ecosystem could not survive.
Native peoples recognized the importance of pollinators in cultural symbolism, as well as in growing food and medicinal plants. They were the first to recognize the role of pollination and to plant corn in such a way that they could hybridize certain types of corn for particular purposes. Native Americans are known as the “first hybridizers” for their scientific talents in cross-pollination and hybridization.
What are the threats to pollinators? One of the main threats is habitat loss. When roads, manicured lawns and non-native gardens replace native vegetation, pollinators lose the food and nesting sites necessary to their survival. Improper use of pesticides can also negatively impact pollinators and their habitat (you’ve probably heard about colony collapse and neonicotinoids).
How can we help the birds, bees, and butterflies? For those of us with gardens, even if just in a few pots, here are some things we can do to help pollinators.
1. Choose native plants in a variety of shapes and colors to encourage diversity. Native wildflowers will be better adapted to your climate than exotics. Results of a recent study in the journal Nature suggested that removal of exotic plants appeared to make native plants more accessible to pollinators.
2. Make sure something is blooming each season (spring, summer, and fall). Some bee species are active all year, some only in April and May, while others in July and August, and all need to feed regardless of the date.
3. If you have a vegetable garden, border them with native flowers, which will support pollination of your crops and support bees, when the crops stop blooming.
4. Avoid pesticide use.
Derry MacBride, of the Garden Club of America put it succinctly: “A garden is only as rich and beautiful as the integral health of the system; pollinators are essential to the system- make your home their home.”
With spring on its way, come for a nature walk on Mt. Sutro. You can also visit us at the Sutro Native Plant Nursery, to find many pollinator-friendly native plants for purchase. The nursery is open every Wednesday from 9:30 am-12:00 pm. Visitors and volunteers are welcome!
Some plants that pollinators like:
Phacelia (Phacelia californica) A perennial herb that is attractive to bees and butterflies. Leaves are up to 8 inches long, with the lower ones divided into several leaflets. Purple flowers are hairy and bell-shaped, and blooms March to September. A native to coastal California and Oregon, the species is a food source for the Mission Blue Butterfly, an endangered species endemic to San Francisco.
Coast Buckwheat (Eriogonum latifolium) Perennial herb, grows 1-3 feet, blooms summer through fall. Blue and green hairstreak butterflies especially like buckwheat and many of these species suffer from dwindling habitat. Buckwheat flowers seem to last forever, turning a chocolate color in the fall. They are very drought tolerant and can survive many arid environments.
California Poppy (Eschscholzia californica) California’s beloved State Flower is a popular perennial wildflower. Its blue-green leaves are highly dissected with yellow or orange flowers opening only on sunny days. Blooms February to October. Easy to grow, drought tolerant, and easily reseeds itself. Bumblebees love them.
Hummingbird Sage (Salvia spathacea) An herbaceous plant species with woody bases and upright flowering stems, this fruity-scented Salvia blooms in March to May with typically dark rose-lilac colored flowers. The entire plant is covered with wavy glandular hairs making it soft to the touch. Part of the mint family, it’s highly aromatic when touched or crushed. Hummingbird sage likes dry shaded or partly shaded areas, and is drought tolerant. Attracts hummingbirds, bees and butterflies.
Why is Pollination Important for Wildflowers? USDA Forest Service. https://www.fs.fed.us/wildflowers/pollinators/importance.shtml
Pollinator Plants California. The Xerces Society for invertebrate conservation. http://www.xerces.org/wp-content/uploads/2014/09/CaliforniaPlantList_web.pdf
Threats to Pollinators. US Fish and Wildlife Service. https://www.fws.gov/pollinators/PollinatorPages/Threats.html
Restoring native plants ‘boosts pollination’. Helen Briggs. BBC News. http://www.bbc.com/news/science-environment-38800967
Selecting Plants for Pollinators. A Regional Guide. Pollinator Partnership and NAPPC. http://www.pollinator.org/PDFs/Guides/CalifCoastalStepperx4FINAL.pdf
Eschscholzia californica . California Poppy. Lady Bird Johnson Wildflower Center Plant Database. http://www.wildflower.org/plants/result.php?id_plant=ESCA2
Gardening in the Dunes. Coast Buckwheat. J. Gomes. Sutro Stewards August 2016. http://www.sutrostewards.org/single-post/2016/08/31/Gardening-in-the-Dunes
California Phacelia. CalFlora. https://www.calflora.org/cgi-bin/species_query.cgi?where-calrecnum=6293
Phacelia californica. Wikipedia. https://en.wikipedia.org/wiki/Phacelia_californica
Hummingbird Sage. Salvia spathacea. California Native Plant Society. http://calscape.org/Salvia-spathacea-(Hummingbird-Sage)