Dahlias are popular garden plants, known for vibrant blooms. While beautiful, they are also a food source for various animals. Understanding which creatures are attracted to dahlias and how they cause damage helps gardeners. This information guides effective protection strategies, ensuring healthy plants and abundant flowering.
Mammalian Pests of Dahlias
Larger mammals cause significant dahlia damage due to their size and appetite. Deer browse dahlia leaves and flowers, typically eating from the top downwards. They are attracted to tender foliage, especially where other forage is scarce.
Rabbits target dahlias, especially young shoots and leaves closer to the ground. They quickly defoliate newly planted dahlias or tender growth. Voles and gophers pose an underground threat by consuming dahlia tubers and roots. These rodents are drawn to starchy tubers, often causing plants to wilt or disappear entirely as their root systems are destroyed.
Insect and Mollusk Pests of Dahlias
Smaller pests, including insects and mollusks, harm dahlias. Slugs and snails feed on young dahlia leaves and flowers, leaving irregular holes and a characteristic shiny slime trail. These mollusks are most active in damp conditions or at night, making their damage sometimes more apparent than the pests. Earwigs, largely nocturnal, chew on tender dahlia leaves and flower buds, often hiding within emerging leaves during the day.
Thrips are tiny, slender insects that suck sap, leading to stippled, distorted, or silvery leaves and flowers. Their feeding can deform or discolor blossoms, and severe infestations stunt plant growth. Spider mites, minuscule arachnids, also feed on plant sap, causing leaves to appear yellow, stippled, or mottled. They thrive in hot, dry conditions and often create fine webs on the undersides of infested plants. Aphids are small, soft-bodied insects that cluster on new growth, sucking sap and causing yellowing, curling, or distorted leaves, often leaving behind a sticky honeydew substance.
Identifying Damage to Dahlias
Diagnosing dahlia damage involves distinct visual cues. Clean cuts on stems or leaves often indicate feeding by larger animals like deer or rabbits. Ragged holes in leaves and petals, especially accompanied by a silvery slime trail, point to slugs or snails. If plants are entirely missing or show signs of tunneling around their base, voles or gophers are likely culprits, as they consume underground tubers.
Distorted growth, silvery streaks on leaves, or a stippled appearance are common signs of thrips activity. Spider mites cause yellowing or bronzing of leaves, often accompanied by fine webbing, particularly on the undersides of foliage. Sticky honeydew, sometimes leading to sooty mold, along with curled or yellowed leaves, indicates an aphid infestation. Checking for pest droppings or animal tracks near affected plants can provide further evidence to identify the pest.
Protecting Dahlias from Pests
Protecting dahlias from pests involves a combination of strategies, starting with physical barriers. Tall fences deter deer, while shorter fences or cages around young plants keep rabbits away. For slugs and snails, copper tape placed around plant beds creates a barrier they avoid, and diatomaceous earth sprinkled around plants is also effective. For earwigs, traps made from upturned pots filled with straw can lure them away from plants for relocation.
Cultural practices aid pest prevention. Maintaining garden hygiene by removing debris and weeds reduces hiding places for pests like earwigs and slugs. Proper watering, avoiding excessive moisture, makes the environment less appealing to slugs and snails. Companion planting with certain herbs or flowers, such as marigolds, garlic, or basil, deters pests like aphids and beetles.
Repellents offer another defense against mammalian pests. Commercial sprays formulated to deter deer or rabbits can be applied to foliage. Some gardeners use homemade solutions or natural deterrents like coyote or cougar urine to create an undesirable scent. Manual removal, such as hand-picking slugs and snails (especially at night) or trapping earwigs, can directly reduce pest populations.
For insect pests, organic sprays provide a targeted approach. Neem oil, derived from the neem tree, acts as an insecticide and deters feeding for pests including aphids, spider mites, and earwigs. Insecticidal soaps are effective against soft-bodied insects like aphids, thrips, and spider mites by suffocating them.
Regular water sprays dislodge spider mites and aphids. Encouraging natural predators like ladybugs and lacewings helps control aphid populations, while predatory mites manage spider mites. Starting with less toxic methods and observing pest activity helps maintain an integrated pest management approach.