“Carpenter plant” isn’t a specific botanical term; it refers to plants and garden structures affected by carpenter insects, primarily carpenter bees and carpenter ants. These insects are known for their wood-boring activities, which can impact wooden elements in a garden or landscape. While they do not directly harm living plants for nesting, their presence can concern gardeners. This article clarifies their interactions with plants, helping gardeners understand and manage them.
Carpenter Bees and Plant Interactions
Carpenter bees (genus Xylocopa) are often found near gardens due to their nesting preferences and role as pollinators. These bees do not consume wood but bore into soft, untreated, or weathered wood to create tunnels for their nests. Common nesting sites include wooden garden beds, trellises, fences, decks, and dead tree limbs. Unlike social bees, carpenter bees are largely solitary, with females constructing and managing their own nests.
While their wood-boring habits can be a nuisance, carpenter bees are important pollinators for many flowering plants, including various garden crops. They forage on nectar and pollen, contributing to the fertilization of plants as they move between flowers. Carpenter bees are attracted to flowers with abundant nectar and open or shallow blossoms, such as daylilies, zinnias, salvia, bee balm, asters, lavender, and oregano. They are also known for “buzz pollination” (sonication), where they vibrate their bodies to release pollen from certain flowers, like tomatoes and eggplants. They are beneficial insects for garden ecosystems, despite potential damage to wooden structures.
Carpenter Ants and Plant Associations
Carpenter ants, unlike carpenter bees, do not bore into healthy, live plants for nesting. Their primary nesting preference is damp, decaying wood, such as old tree stumps, rotting logs, or moist structural wood near gardens. These ants excavate galleries within wood for nests but do not consume the wood itself. Their presence in wooden garden elements often indicates moisture problems or wood decay.
Carpenter ants have an indirect association with plants, especially through sap-sucking insects like aphids. Aphids excrete honeydew, a sugary liquid, as they feed on plant sap; this is a favored food source for many ant species, including carpenter ants. Ants “farm” aphids, protecting them and moving them to succulent plant parts for honeydew. Therefore, a noticeable presence of carpenter ants on your plants often signals an aphid infestation, not direct ant damage. While carpenter ants don’t harm live plants directly, their presence can worsen aphid problems, negatively impacting plant health.
Recognizing Signs of Carpenter Insect Activity
Identifying carpenter insect activity near your plants involves observing specific visual cues and sounds. For carpenter bees, a clear sign is the presence of perfectly round entry holes in wooden structures, typically about a half-inch in diameter. These holes are often in unpainted or weathered softwood, such as garden trellises, raised beds, or patio furniture. Below these holes, you might notice piles of sawdust-like wood shavings, known as frass, which the bees expel as they tunnel. A buzzing sound around these wooden areas, especially during warmer months, indicates active excavation.
Carpenter ant activity shows different signs. Observe visible ant trails, particularly at night, leading to or from wooden structures or plants. Their wood excavations produce coarse, sawdust-like frass, often containing insect body parts and wood fragments. This frass is pushed out of nest openings and can accumulate in small piles. Unlike carpenter bees, carpenter ants prefer nesting in damp or decaying wood; inspecting soft or compromised wooden elements helps locate them.
Managing Carpenter Insects Near Your Plants
Managing carpenter insects near your plants involves addressing their nesting preferences and food sources. For carpenter bees, preventative measures focus on protecting wooden structures. Sealing and painting exposed, untreated wood in your garden, such as arbors, pergolas, or shed eaves, makes it less attractive for nesting. Applying a fresh coat of paint or varnish every few years helps deter them, as they prefer bare or weathered surfaces.
Physical barriers, like netting or screens, can also cover vulnerable wooden areas during their active season in spring. Non-toxic deterrents, such as citrus-based sprays or loud noises, are sometimes suggested with varying effectiveness.
For carpenter ants, management strategies involve eliminating their preferred nesting sites and controlling their food sources. Removing decaying wood, old tree stumps, and rotting logs from your garden significantly reduces potential nesting locations. Addressing moisture issues, such as leaky irrigation systems or poor drainage, helps prevent wood decay that attracts these ants.
Since carpenter ants are often drawn to plants by aphid honeydew, managing aphid populations on your plants is important. This can be done by regularly rinsing plants with a strong stream of water or using insecticidal soaps. Maintaining overall garden cleanliness by removing fallen fruits or food debris also reduces their foraging opportunities. For extensive infestations or when carpenter ants are found within structural elements of a home near the garden, professional pest control services may be necessary to effectively locate and treat the colonies.