Plants: J
- Jacaranda Jacaranda mimosifolia Flowering tree
- Jack-in-the-Pulpit Arisaema triphyllum Wildflower
- Jackman Clematis Clematis × jackmanii Garden perennial
- Jacob's Ladder Polemonium caeruleum Wildflower
- Japanese Andromeda Pieris japonica Flowering shrub
- Japanese Anemone Anemone hupehensis Wildflower
- Japanese Apricot Prunus mume Flowering tree
- Japanese Ardisia Ardisia japonica Creeping perennial
- Japanese Astilbe Astilbe japonica Garden perennial
- Japanese Burnet Sanguisorba obtusa Garden perennial
- Japanese Camellia Camellia japonica Flowering shrub
- Japanese Crape Myrtle Lagerstroemia fauriei Flowering tree
- Japanese Flowering Cherry Prunus serrulata Flowering tree
- Japanese Flowering Crabapple Malus floribunda Flowering tree
- Japanese Forest Grass Hakonechloa macra Creeping perennial
- Japanese Garden Juniper Juniperus procumbens Creeping perennial
- Japanese Iris Iris ensata Garden perennial
- Japanese Kerria Kerria japonica Flowering shrub
- Japanese Lily Lilium speciosum Garden perennial
- Japanese Millet Echinochloa esculenta Grain
- Japanese Morning Glory Ipomoea nil Garden annual
- Japanese Pachysandra Pachysandra terminalis Creeping perennial
- Japanese Pagoda Tree Styphnolobium japonicum
- Japanese Painted Fern Athyrium niponicum Creeping perennial
- Japanese Plum Yew Cephalotaxus harringtonia Low shrub
- Japanese Primrose Primula japonica Garden perennial
- Japanese Quince Chaenomeles japonica Flowering shrub
- Japanese Sedge Carex morrowii Grass sedge
- Japanese Spirea Spiraea japonica Flowering shrub
- Japanese Stewartia Stewartia pseudocamellia Flowering tree
- Japanese Stonecrop Sedum makinoi Creeping perennial
- Japanese Tree Lilac Syringa reticulata Flowering tree
- Japanese Zoysia Zoysia japonica Creeping perennial
- Jelly Bean Plant Sedum × rubrotinctum Succulent
- Jerusalem Artichoke Helianthus tuberosus Root
- Jerusalem Sage Phlomis fruticosa Flowering shrub
- Jewelweed Impatiens capensis Wildflower
- Joe Pye Weed Eutrochium purpureum Wildflower
- Johnny Jump Up Viola tricolor Wildflower
- Jonquil Narcissus jonquilla Bulb
- Jostaberry Ribes x culverwellii Berry
- Judd Viburnum Viburnum × juddii Flowering shrub
- Jujube Ziziphus jujuba Tree fruit
- Jungle Geranium Ixora coccinea Flowering shrub