Your flowers may be pleasing to the eye, but the flower bed itself can hide a nasty surprise in the form of underground nesting bees and wasps. These may emerge and attack you while you're enjoying your landscape or working among your plants. Such nests can have multiple exits and may cover a surprisingly large area under a garden bed. Treat these underground nests with insecticide to kill any underground bees and wasps and restore safety to your backyard.
Use pruning shears to trim back any flowers near the nest so that you can approach the area easily without disturbing the plants or ground, thereby causing inquisitive bees to emerge.
Monitor the underground bee or wasp nest to ensure there is just one exit. Sometimes, an underground nest will have multiple holes through which the bees or wasps can fly and attack you if you're not paying attention. Once you've identified the exit holes, wait until the early evening when the insects are less active.
Insert a funnel into any one of the exits from the underground bee or wasp nest.
Pour 32 oz. of liquid pyrethroid compound-based insecticide intended for bee and wasp control into the funnel, directing the liquid into the underground nest. Example compounds include allethrin, cyfluthrin and sumithrin, all available in commercially prepared bee and wasp products at most retail outlets and nurseries. The chemicals kill the insects upon contact.
Exit the area immediately. Wait for 24 hours before returning to the nesting area. Observe the area for any bee or wasp activity. The nest should be dead, but it may need retreating if it is an extensive underground network and some insects survived.