A bee swarm. (July 10, 2010)

Over the past few weeks we have had two or three honeybee swarms here at the nursery. If you are an avid gardener or outdoor enthusiast, you're probably accustomed to bee swarms, especially during this time of the year. At the nursery, these swarms immediately become a huge curiosity.

Did you see all of those bees? Are they angry? Are they looking for a person to attack? Are they lost? Are they looking for their hive?

To most, the sight of a bee swarm induces unusual, often contradictory emotions — beautiful and frightening at the same time. In others, it causes a feeling of curiosity and appall, like driving by a bad accident. You want to look, but at the same time you're afraid you might see something you don't want to.

A swarm of honeybees is capable of reducing the most fearless person to a shaking bowl of jelly. It exhibits sheer terror. During last Saturday's afternoon's swarm at the nursery we overheard comments of "call the fire department," "call the police" and "hurry, get some insecticide." Mothers grabbed their children. Others shrieked, hurrying for cover.

The reality of a bee swarm is quite different from the appearance. They are normally of no real danger and honeybees are usually at their most docile while in a swarming state.

Watching honeybees pour forth from a hive by the thousands, then swirling in the air like a tornado, all the time sounding like a runaway express train, then accumulating into a buzzing football-size mass, is one of nature's most awesome scenes.

What is this swarming about? Are they preparing to attack a helpless human at any moment? Not at all. They are simply engaged in a brief process to propagate their species.

A normal honeybee hive will go through the winter with a population of about 12,000 bees. Early in the season, the queen bee will start laying eggs to build up the population two, three or even four times larger so as to maximize potential during the flowering season. More bees mean more nectar, which is turned into honey as food for the upcoming winter.

When a beehive sees that it is running out of room to store its honey, the bees know it is time for the hive to split and for part of the group to seek a new location and begin a new hive. Worker bees anticipate this need and build special cells within the hive. The workers then induce the queen to lay eggs in these special cells, which are then filled with royal jelly. As the egg becomes a larva, the cell is sealed. This unique process creates new queen bees.

When the first queen emerges, she immediately rushes to each of the other queen cells and thrusts her stinger through the wax seal to kill any queen rivals.

Because there is only room for one queen in a hive, the original queen will prepare to leave. In anticipation for moving day, worker bees gorge on honey. They will need enough energy to sustain themselves until they can establish a new colony and a new honey supply elsewhere.

When the weather is just right, the original queen takes flight and lands randomly on a tree branch, a car bumper or even a signpost. About half of the bees, usually several thousand, follow her in a search for a suitable location for a new hive.

The thousands of swarming bees circling in the air resemble a tornado funnel and produce the sound of a railroad train. Although the bees appear to be mad, they are actually sniffing the air to detect a pheromone given off by the queen. Like the light in a lighthouse, this scent directs the swarming cloud to where the queen bee has alighted. The swirling bees slowly diminish as they gather around the queen and soon form a large, dense mass. This is what most people see when they spot a bee swarm.

During swarming time, these bees have no juveniles and no honey to protect, and they're well fed. Because of this, bees in a swarm are surprisingly docile and far less aggressive than when tending a hive. The police, fire department and National Guard do not need to be called.

After a rest, usually an hour, but sometimes a day or two, the swarm will move on in its search for a location for a new hive. Once found, the workers will immediately begin building new comb. When the cells are ready the queen lays her eggs and a new hive will be established.

If you see a swarm in the next few weeks, don't panic. Instead, try to appreciate the amazing beauty of the swarm and the natural process you are witnessing. It will be gone shortly.

Ron Vanderhoff is the nursery manager at Roger's Gardens, Corona del Mar.

Ask Ron

My zucchini squash seems to have a white fungus on the leaves. What can I do?

Cherie, Laguna Beach


What you are seeing is powdery mildew, a very common occurrence on squash, cucumbers and melons, especially in coastal gardens. I suspect that powdery mildew will be especially prevalent this year, due to the cloudy, cool weather we are having.

First, try to give the plants as much air circulation and sunlight as possible. Crowded or shady conditions, with stagnant air movement will encourage the disease. Contrary to popular myth, frequent rinsing of the foliage will help reduce the problem. If fungicides are needed, use the least toxic product available. I suggest either neem, a naturally occurring extract, or Serenade, which is a biological control.

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 stumpthegardener@rogersgardens.com, or write to Plant Talk at Roger's Gardens, 2301 San Joaquin Hills Road, Corona del Mar, CA 92625.