Honey, I’m home: why bees swarm
Spring and early summer are popular months for moving. Just ask honeybees. Swarm clusters — the proper term for those humming, pulsating, large masses of bees that can suddenly appear on a random tree, fence or other structure — can be intimidating and somewhat alarming. These clusters can consist of tens of thousands of bees, or they can be just (!) a few thousand. Any way you look at it, that’s a lot of bees!
When bees are on the move, they tend to be less aggressive, since they aren’t defending a hive and they are probably tired (moving is exhausting for bees, too). This does not mean you can get away with throwing rocks at or spraying them with a hose. Everyone has their limits.
When you see a swarm hanging out in a tree or on a fence, rest assured that they will likely be on their way in a day or two. Most of the workers and their queen will take their rest while a few workers venture out to find a suitable place to build a new hive. Once they have found it, they return and lead the rest away to their new home.
Hopefully, the new home is an out-of-the-way, hollowedout tree and not your attic, chimney, irrigation box, garden shed or interior walls.
If the swarm is hanging out on the side of a building and appears to be shrinking in size but not leaving, the bees may be busy establishing a hive inside that building. Keep this in mind if that building happens to be your house.
Relocating a hive is much easier when it’s just getting started. Don’t wait to seek help until the hive is established and everyone’s settled in. Some beekeepers will relocate hives, but if the hive is too big the process can become very difficult and expensive. In many cases, you will have no alternative but extermination.
Why do bees swarm? In most cases, it’s because the colony has gotten too big and needs to split. A portion of the workers leave, along with the old queen, and a new queen develops to take over the old hive. Sometimes the entire hive will relocate if there is a shortage of food or water, disease or pesticide exposure.
Since honeybees are so important for our food supply (over 90% of crops grown in California depend on honeybees for pollination), it’s in our best interest to do what we can to maintain a healthy population. Plant nectar-producing, bee-friendly flowers such as salvia, lavender, coreopsis, penstemon, alyssum, catmint, bee balm and other natives. If you have a birdbath, place a few pebbles in it to provide a shallow landing spot for thirsty bees and butterflies.
Have questions? Email gardening@scng.com. For more master gardening resources, visit ucanr. edu/sites/RiversideMG for Riverside County; mgsb. ucanr.edu for San Bernardino County; celosangeles.ucanr. edu/UC_Master_Gardener_ Program for Los Angeles County; and mgorange.ucanr. edu for Orange County.