By Constance Taylor
One out of every third bite you take is because of a pollinator. Butterflies, wasps, hummingbirds, bats, mosquitoes, flies, and of course, bees, all contribute to help plants get it on, filling the bellies of all heterotrophs and keeping us happy (or at least alive).
It was a chilly noon in August as we grouped up to get started of our tour of the pollinator gardens at the Lakeside Gardens at Lake Merritt.
“Hopefully it’ll warm up in a little bit so we can see some insects pollinating these plants!” said Tora Rocha, Oakland Parks Supervisor and our walk leader for the afternoon.
With thirty years of professional gardening experience under her belt and a three-year veteran of her current post with the city, Rocha is a font of information when it comes to pollinators, the plants they like, and the history of the Lakeside Gardens.
“For the past fifteen years the gardens have had a pesticide- and herbicide-free policy,” said Rocha. “We also rely on volunteers contributing thousands of hours to keep our parks maintained- about 75% of the work is done by volunteers.”
“As the Parks Supervisor it’s not enough to be a custodian of these areas, I also have to be a steward. I started thinking about planting pollinator gardens when I noticed monarchs roosting in the tops of the Dawn redwoods in the winter.”
Rocha began collecting monarch caterpillars from the milkweed in the garden and hand-raising them at home until she could release them as butterflies back into the garden. After everyone from kids to city council members started approaching Rocha asking if they, too, could have a caterpillar to raise, she started a group called the Pollinator Posse.
The Pollinator Posse is a loose contingent of folks interested in raising pollinators and protecting their habitat, establishing pollination corridors, and educating others about the importance of pollinators. Anyone can join, and one of their main tasks is to rear caterpillars to butterflies for release into the Lakeside Gardens.
As Rocha was telling us about the Pollinator Posse, a monarch floated past.
“You normally wouldn’t see monarchs around this time of year, but we’ve released over 250 monarchs since the beginning of 2013. That’s why you’ll see them in the park even if you might not see them anywhere else in the city.”
Although the gardens work to provide everything a pollinator needs, it doesn’t hurt to have a human benefactor assist on the road to caterpillar adulthood.
“Butterflies and caterpillars are at the bottom of the food chain- almost everything eats them. The number of caterpillars we’re taking off plants to hand-raise aren’t enough to diminish the food supply for other animals- we’re just helping boost survival rates until the butterfly can reproduce” says Rocha.
Pollinator habitat needs three basic things: Host plants, Shelter, and Nectar plants
The specific definitions of what a host, shelter, and nectar plant are start to vary depending on the pollinators you’re trying to attract- hummingbirds and bees, for example, may require different host, nectar, and shelter plants than butterflies (although there’s quite a lot of crossover).
So, as an example, let’s consider the butterfly. Host plants are the plants that the adults lay the eggs on- when the eggs hatch into caterpillars, the caterpillar will stay on the host plant and eat until it’s ready to shed its skin for the final time and expose the chrysalis.
Milkweed is the only host plant monarchs can survive on, but other host plants will attract a number of general Bay Area pollinators. Cudweed, mallow, California native grasses (like Festuca californica and Carex praegracilis), and native buckwheats all appeal to a wide range of pollinators.
It’s important to consider where you’re putting your host plants. You don’t want to maroon your baby pollinator on an island with nowhere to go- they need a safe place to go into and come out of their chrysalis form. They’ll often move from the host plant to another plant for this stage, and they’ll try to get to the highest place possible to enter into chrysalis. So consider planting your hosts near trees or another kind of shelter instead of an isolated patch in your lawn.
Once the butterfly emerges, it’ll need nectar to eat! This usually requires yet another plant (or plants) like California poppies, Coreopsis, Asters, Penstemons, citrus blossoms, lavender, and native monkey flowers.
“Poppies are the number one plant for nectar, ” said Rocha as she swept her arm above the rainbow array of poppies she stood next to, some native, some not. “We’ve planted a diverse selection that bloom at different times of the year- we have poppies flowering here about nine months out of the year.”
The Bee Hotel: Another kind of habitat
One of the newest additions to the Lakeside Gardens is the Bee Hotel. Installed on Earth Day 2013 (April 22), volunteers are still working to pack the spaces with different nesting materials native bees might like.
“This is all an experiment,” said Rocha. “We’re not really sure what kind of substrate the bees will prefer, so we’re trying different things.” Logs with holes drilled seven inches deep, sawdust mixed with mud packed into honeycomb structures, paper straws inserted into drilled holes for extra nesting material- the varied real estate will hopefully attract native bees that would otherwise nest in rotting logs and stumps.
“Every time a tree dies, we have to remove it for the safety of people” Rocha explained. “But when we do that, we’re also removing bee habitat; this hotel is an effort to give the bees somewhere safe to live.”
At least eight species of native bees are found at Lakeside Park, and four of those species will most likely use the bee hotel (the other four nest underground).
Large carpenter bees (Xylocopa spp.), small carpenter bees (Ceratina spp.), leafcutter bees (Megachile spp.) and mason bees (Osmia spp.) have all been spotted investigating the hotel, so it appears to be attracting the intended crowd.
Rocha encouraged us to make our own bee hotels at home- smaller habitats are relatively easy to make and can be mounted on the side of the tree or the outside of a house. She warned us, however, about just mounting something and forgetting about it.
“Unfortunately, with things like bee hotels or bird houses, you can’t just build something and leave it or else wasps will move in. You have to monitor what’s going on and make sure it that stays a good environment for the species it’s intended for.”
If you’re interested in helping pack the bee hotel with more nesting material or getting involved with the pollinator gardens, volunteer work parties are held every first and third Saturday of the month from 9 am to 1 pm. You can find more details on the Friends of the Gardens at Lake Merritt webpage.
More information about the Pollinator Posse can be found on their Facebook page (https://www.facebook.com/groups/PollinatorPosse/)
And if you want to learn even more about the insects that help pollinate all the plants around Oakland, get yourself a free downloadable guide!! “Lake Merritt and Greater Oakland Insects” is available through the Insect Sciences Museum of California. E-mail email@example.com to request a free copy.