Experts and BHG readers answer.
Is there anything Japanese beetles won't eat?
Japanese beetle adults are general feeders, and will eat many landscape plants. A few are less attractive to them than most (see resistant plants, below). Some are especially attractive to Japanese beetles. Avoid growing these plants. Once the beetles start feeding on them, they send out a signal to others that the eating is good, and beetles from hundreds of yards away come flying in to join the feast. Plants resistant to Japanese beetle American holly Ilex opaca 5-9 Dogwood Cornus spp. 2-9 Forsythia Forsythia x intermedia 4-8(9) Ginkgo Ginkgo biloba 4-8(9) Lilac Syringa spp. 3-7 Silver linden Tilia tomentosa 4-7 Tamarisk Tamarix ramosissima (3)4-8 Plants favored by Japanese beetle adults American sycamore Platanus occidentalis (4)5-9 Apple, flowering crabapple Malus spp. 3-8 Astilbe Astilbe x arendsii 3-8 Azalea Rhododendron cvs. 4-10 Blueberry Vaccinium spp. 3-9 Crape myrtle Lagerstroemia indica (5)6-10 Elm Ulmus spp. 2-9 Flowering cherry, peach Prunus spp. 3-9 Flowering quince Chaenomeles speciosa 5-9 Grape Vitis spp. 4-10 Hollyhock Alcea rosea 3-9 Horsechestnut Aesculus hippocastanum 4-7 Japanese maple, Norway maple Acer spp. 4-8 Linden Tilia spp. 2-8 Northern bayberry Myrica pensylvanica (2)3-6(7) Pussy willow Salix discolor 4-8 Raspberry Rubus idaeus 3-7 Rose Rosa spp. 3-10 Rose of Sharon Hibiscus syriacus 5-8(9) Viburnum Viburnum spp. 2-8 Virginia creeper Parthenocissus quinquefolia 3-9