The sudden appearance of holes, ragged edges, or missing blooms in a garden requires careful investigation. Successfully protecting flowers relies entirely on correctly identifying the specific creature responsible for the destruction. Observing the type of damage left behind is the most reliable way to pinpoint the culprit, guiding the gardener toward a targeted and successful management strategy.
Diagnosing the Damage Type
Becoming a garden detective requires close observation of the physical evidence left on the plants. Damage caused by chewing pests can be broadly categorized as either ragged, irregular holes or clean, precise cuts. Ragged edges or holes often point to smaller invertebrate pests like slugs, snails, or various insect larvae. Conversely, stems or buds that have been cleanly clipped off at a 45-degree angle suggest a small mammal with sharp incisors, such as a rabbit. Damage involving extensive browsing at heights up to six feet is typically the work of larger animals like deer. Beyond the plant itself, signs like silvery slime trails confirm the presence of slugs or snails, while small, pellet-like droppings, known as frass, are indicators of caterpillar activity.
Pests That Chew Foliage and Flowers
Small invertebrates cause localized damage using specialized mouthparts. Slugs and snails use a rasping organ called a radula, which leaves behind smooth-edged, irregular holes, often in the center of leaves. The presence of a glistening, silvery trail of dried mucus confirms these mollusks as nighttime feeders. Caterpillars leave jagged, uneven holes, frequently consuming the plant from the edge inward. Their presence is confirmed by frass, which are tiny, round pellets of excrement found near the feeding site.
Other nocturnal chewers include earwigs, which leave ragged holes in tender flower petals, particularly on blooms like dahlias and zinnias. Beetles, such as the Japanese beetle or spotted cucumber beetle, typically feed during the day, skeletonizing leaves by eating the tissue between the veins or creating small, symmetrical holes in petals. While these pests often cause aesthetic damage, heavy populations can severely weaken or destroy young seedlings.
Larger Mammals and Their Distinct Feeding Habits
Mammals cause more significant damage, often removing entire sections of plants in a single feeding session. Deer lack upper incisors, forcing them to pinch and pull the vegetation, which leaves behind ragged, torn, or shredded plant material. This damage is often concentrated in a browse line up to six feet above the ground. Rabbits, equipped with sharp front teeth, make clean, precise cuts, often shearing young plants off near the base at a recognizable 45-degree angle. Their low stature means the damage is concentrated close to the ground, and small, pea-sized droppings nearby confirm their activity.
Squirrels and chipmunks cause indirect damage through caching behavior, frequently digging up newly planted bulbs like tulips and crocuses to eat the contents. They also sometimes clip flower heads from plants like sunflowers or tulips. Below-ground damage is often the result of voles and gophers. Voles gnaw on roots and bark near the soil line and create surface runways, while gophers pull entire plants down into their tunnels and create distinctive, fan-shaped dirt mounds with a plugged center hole.
Effective, Non-Toxic Management Strategies
Once the culprit is identified, non-toxic strategies focus on creating physical barriers or using taste and scent deterrents. For small mammals like rabbits and voles, a physical barrier of 1/4-inch hardware cloth or chicken wire can be buried a few inches into the soil to prevent digging and chewing. Deer require much taller exclusion fencing, typically at least eight feet high, to effectively block their access to the garden. Protecting bulbs from squirrels and chipmunks involves planting them inside wire cages made of hardware cloth or covering the area with a layer of mesh after planting.
Cultural controls are useful for smaller pests, such as removing leaf litter and debris where slugs and earwigs hide during the day. Altering watering practices to irrigate in the morning instead of the evening also reduces the damp, moist conditions favored by slugs. Repellents work by making the plants taste or smell offensive, often utilizing ingredients like putrescent egg solids or capsaicin. These products must be reapplied frequently, especially after rain or new plant growth. Simple techniques like tamping down soil after planting bulbs can also hide the scent and make the area less appealing for foraging rodents.