The Coastal Gardener: Native pollinators can help with fruit, vegetables

If you’re like many home gardeners, you may have added fruit trees to your garden in the past two years.

Maybe a peach or an apricot, or even a few citrus or dwarf avocado. Maybe you’re more into grapes and berries. Perhaps you’re more the vegetable type and started growing your own tomatoes, cucumbers, squash and others.

Did you know that all of these fruits and vegetables need to be pollinated to produce crops? You can reliably improve pollinations of all your fruits and vegetables by attracting the right insects. Non-native European honey bees are our most famous pollinator, but most gardeners can’t do much to lure these into their gardens.

Ever wonder what pollinated our crops before honeybees were introduced from Europe?

Native mason bees, also known as orchard mason bees, have been pollinating plants for millennia and are still at work, even though most people aren’t very aware of them. Even if you saw one, you might think it was just a funny looking honeybee.

Honeybees don’t like to leave their hives to forage on cold or rainy days, but mason bees are much more rugged and don’t mind a little inclement weather, a cold spring day or a drizzle, so whether you have an orchard or just a few vegetables, mason bees will help improve your yields.

Mason bees look superficially like honey bees but differ in several ways that a home gardener may prefer. Perhaps most important, mason bees are solitary insects. Unlike honeybees, they do not build hives and do not make honey.

Another important distinction is that, since they have no queen or hive to protect, mason bees are very docile and will almost never sting. Even if you caught one in your hand and tried to provoke it to sting, the pain is quite mild, about the same feeling as being bitten by a mosquito.

To attract these beneficial insects to your property, you need to understand their nesting habits and living patterns. Mason bees need a steady source of flower nectar during their breeding season, as well as nesting sites where they can lay their eggs and where their juveniles can spend the winter. In nature, mason bees nest in narrow holes found in old trees or in hollow plant stems.

Female mason bees lay their eggs in these hollowed out, tube-like holes. As the female lays an egg inside the hole she adds pollen and nectar for the young to feed on. Then she adds another egg and more pollen and nectar, until the hole is filled. Once the space is full the female closes off the end with a dab of mud. Fortunately, a clever gardener can replicate these nesting holes rather easily in a garden.

One method is to drill several holes, four inches to six inches long, into a block of untreated soft wood such as pine or fir. Don’t drill the holes all the way through the wood; mason bees prefer tubes with only one end open.

The diameters of the hole should vary a little bit if possible and be between a quarter-inch and three-eighths of an inch in diameter. Hang or mount the wood block near some flowering fruit trees or vegetables.

Another simple mason bee nesting house can be made with small bamboo poles. Select a few unpainted bamboo poles at a nursery — the same ones used to support plants like foxgloves and delphiniums. Choose poles that have hollow centers about the right size.

Cut a piece of the bamboo, just behind a joint. This will be the closed end of the tube. Cut the open end of the bamboo about four to six inches long.

Now bundle about 30 to 50 of these cut bamboo pieces together and line up their open ends grouping has a flat front. With some twine or soft wire, tie the whole group firmly together. Attach another piece of twine or wire so that you can hand the nesting tubes from a tree or overhang.

If you don’t want to build your own mason bee nesting home, you can also purchase nesting tubes and blocks from some on-line sources. One of the best is Knox Cellars (https://www.knoxcellars.com).

Pollinators are an important factor in a healthy garden, and I recommend mason bees to both help with your yields as well as a way to support local wildlife.

Mason bees are native, basically don’t sting, don’t build hives, are good pollinators and are a great way to have some fun while learning a bit more about our natural eco-systems.

RON VANDERHOFF is the nursery manager at Roger’s Gardens, Corona del Mar

Ask Ron

Question: Can you suggest a couple of evergreen trees for a coastal bluff? Lots of salt air and wind.

Joan

Corona del Mar

Answer: Two good choices include New Zealand Christmas Tree (Metrosideros excelsa) and Pink Melaleuca (Melaleuca nesophila). These will handle a challenging oceanfront environment especially well.

ASK RON your toughest gardening questions, and the expert nursery staff at Roger’s Gardens will come up with an answer. Please include your name, phone number and city, and limit queries to 30 words or fewer. E-mail [email protected], or write to Plant Talk at Roger’s Gardens, 2301 San Joaquin Hills Road, Corona del Mar, CA 92625.