There are fewer bees this year. Gardeners can do something about improving insects’ odds

Like many bee-lovers, I often try to identify the bees that frequent my garden, check out which plants they’re visiting most, and estimate the bee count.

Although there seem to be many more flowers this wetter, cooler year, there seem to be fewer bees. The wax privet outside the bedroom window had at most half the usual number of bee visitors earlier this spring, our fountain that provides water for thirsty bees on hot days has had no bee visitors, and the fruit set on my Meyer lemon tree that is normally abuzz with pollinating bees in late spring is bearing a very light crop of lemons this year. In this case, scientific evidence backs up my anecdotal observations.

According to a recent newspaper article written by Seth Borenstein with The Associated Press, the annual bee count of the Bee Informed Partnership found that over 35% of honeybee colonies died this winter. That’s nearly 9% above the average winter die-off.

Winter weather was harsher than normal across much of the U.S., but that is not the only possible explanation for this above-normal bee loss. Pesticide use, loss of habitat and food, diseases and mites have been blamed for the decline in bee populations over the last decade. Dennis Van Englesdorp, president of the Bee Informed Partnership, suspects that the primary cause of this winter’s bee colony loss may be mite infestations.

What can central San Joaquin Valley home gardeners do this summer to help our remaining bees survive and stay healthy enough to make it through winter?

It’s too hot and too late in our summer planting season to replace non-flowering plants with those that attract bees. That should be done in September when temperatures are cooler. The most important and first step is to keep existing flowering plants blooming by deadheading them regularly to prevent seed heads from forming. After seed heads form, plants slow or stop flower production.

Feed lightly and consistently every month with lower-nitrogen, higher-phosphorus granular fertilizers that will release nutrients more slowly. Consider switching to organic fertilizers rather than chemically formulated types. Reducing the amounts of chemicals that are used in our gardens including fertilizers, pesticides and herbicides can protect bees.

Foraging bees need sources of clean, clear trickling water nearby their food sources. Gently-rotating oscillating sprinklers, drip emitters, fountains, or ponds with running water can provide water to quench their thirst.

Thirty percent of our California native bees nest above ground. In our urban gardens, we see mostly leafcutter bees (the ones that cut out half circles in our rose leaves) and mason bees. Bee houses for cavity-nesters can be purchased or easily made by hand. The UC Davis paper, “How to Make and Use Bee Houses for Cavity-Nesting Bees” gives instructions. Other bees build nests in undisturbed soil. Consider leaving a small dirt patch or two in your landscaped urban garden for the bees to make their home.

The UC Berkeley Urban Bee Lab website, www.helpabee.org, also provides information on bee houses and has a comprehensive list, “Gardening for Bees-Seasonal Recommended Plant Lists.” Just reading this list is educational. It describes bee species (including native California bees and European honeybees), when they’ll be foraging in the garden and which plants attract which bees. Use it to inspire your design plans for the September/October prime planting season.

This story was originally published July 3, 2019 at 12:00 AM with the headline "There are fewer bees this year. Gardeners can do something about improving insects’ odds."