Unlike human beings, plants are not prone to kill the goose that lays the golden egg. Since about 80 percent of flowering plants rely on insect pollinators to propagate their species, don't expect to find many that exude substances that repel bees and wasps. However, certain plant extracts may help to keep bees and wasps at a distance.
Pollination is a Plants' Priority
Bees are the leading insect pollinator, and have developed an interdependence with the majority of flowering plants over the last million or so years. The bee population is currently in decline due to human intervention, not plant animosity. Without bees, the world as we know it would be over.
Wasps play an important role in pollination as well, since they feed on small insects that damage flowers. They also attack pest insects like the house fly and blow fly larva.
"As Bitter as Wormwood"
If any plant repelled bees and wasps, it would likely be wormwood (Artemisia absinthium), a woody perennial with silvery foliage. The leaves are aromatic, and every part of the plant is so bitter that it inspired the old expression: "as bitter as wormwood." Wormwood grows in U.S. Department of Agriculture plant hardiness zones 4 through 8.
Many sources claim that wormwood repels wasps, and, in ancient days, country people wore a sprig behind an ear for just that purpose. While this may be true, you will find little scientific support for the proposition. If you do decide to plant wormwood around your patio, keep in mind that the leaves and stems are poisonous.
Plant Extracts to Ward Off Bees and Wasps
Some use oils made of plant extracts, alone or as part of a mixture, to repel insects. Experts at the University of Arizona suggest you try products with mint oil against wasps. Other oils reputed to repel bees or wasps include citrus oil and eucalyptus oil. Some experts insist that there is no scientific support for this, while others insist that there is.
A scientific study released in June, 2015, by experts at Sterling International, Inc. provides support for the claim that plant extracts can be effective against wasps. The researchers found that 17 of the 21 plant extract compounds they tested repelled yellow jackets and paper wasps. They concluded that the plant extracts have great potential for efficient, environmentally sound ways of repelling wasps.