Wasps are often seen as aggressive summer nuisances, yet they maintain a complex relationship with the plant kingdom, acting as both pollinators and predators. The vast majority of the world’s many thousands of wasp species are solitary and non-aggressive, playing significant roles in regulating insect populations and supporting plant health. Understanding which botanical characteristics attract these insects and which ones repel them allows homeowners and gardeners to better manage their outdoor spaces. By making informed planting choices, a gardener can encourage beneficial wasps for natural pest control or discourage unwanted social species from interfering with outdoor activities.
Understanding Why Wasps Seek Out Plants
Wasps visit plants for functional reasons that support different stages of their life cycle and the needs of their colony. Adult wasps, much like bees, require a diet rich in carbohydrates, which they obtain primarily from plant nectar and sweet secretions. This sugary fuel source provides the energy necessary for their daily activities, including foraging and nest maintenance. Wasps with relatively short tongues are particularly drawn to shallow, open flowers where the nectar is easily accessible.
The next major motivator for a wasp’s plant visit is the pursuit of protein for their developing larvae. Many adult wasps are predators or parasitoids, hunting or laying eggs on other insects found on specific plants. Plants that attract pests like aphids or caterpillars effectively become hunting grounds, offering a direct food source for the carnivorous larval stage. Social wasps, such as hornets and yellow jackets, also seek out wood fibers or pulp from trees and shrubs to construct their distinctive paper nests.
Specific Plant Types That Attract Wasps
Plants that feature easily accessible nectar are highly attractive to adult wasps seeking an energy boost. Species with flat, open flower clusters, known as umbels, are particularly favored because they provide a stable landing platform and shallow nectaries. The nectar in these flowers is readily available to wasps with their shorter mouthparts. Examples of these include herbs and wildflowers such as:
- Fennel
- Dill
- Yarrow
- Queen Anne’s Lace
Beyond nectar sources, wasps are also drawn to plants that host an abundance of prey insects or produce sweet, decaying matter. Sunflowers offer a dual attraction, providing both ample nectar and a habitat for small pests like aphids, which serve as protein for wasp larvae. Fruit-bearing plants, such as raspberry bushes, can also draw wasps, especially in late summer when fallen or overripe fruit begins to ferment and exudes a highly concentrated sugar source. Some plants, including certain fig species, rely entirely on specialized wasps for pollination.
Plants Used as Natural Wasp Deterrents
Many plants function as natural wasp deterrents by emitting strong volatile organic compounds that interfere with the insects’ chemical senses. These plants are characterized by their potent, pungent aromas, which wasps find unappealing or overwhelming. Positioning these species strategically around outdoor seating areas or windows can create an effective barrier against nuisance wasps. The repellent effect results from the disruption these compounds cause to the wasp’s navigation and foraging instincts.
Strongly scented herbs are among the most effective deterrents:
- Mint
- Basil
- Thyme
- Lemongrass
Lemongrass contains citronellal, the same compound found in citronella, which wasps actively avoid. Ornamental plants also play a role; Marigolds and Geraniums emit scents that discourage wasps from lingering in the area. Geraniums’ strong fragrance makes them a practical choice for pots on patios.
Distinguishing Between Beneficial and Nuisance Wasp Species
The wasp species encountered in a garden can be classified into two groups based on their social behavior and impact on humans. Beneficial wasps are largely solitary species, such as parasitic wasps, mud daubers, and thread-waisted wasps, which are not aggressive toward people. These species are highly valuable for natural pest control, as they paralyze and provision their nests with garden pests like caterpillars, flies, and spiders. Gardeners can attract these beneficial wasps by planting the shallow-flowered plants mentioned earlier to provide necessary nectar.
In contrast, nuisance wasps are social species, primarily Yellow Jackets, Hornets, and Paper Wasps, which live in large colonies and aggressively defend their nests. These are the species responsible for most stings and are particularly drawn to human food and drinks, especially sugary items, in late summer when natural nectar sources decline. The deterrent plants discussed are most effective against these social, aggressive species, helping homeowners enjoy outdoor spaces without confrontation.