| Liquidambar styraciflua | American Sweetgum | | Big Trees in Winter, Wet Site Plants; Wet Site Plants | Tree > 30 feet, Deciduous, Full sun, Zone 5b, Can tolerate acid to neutral soil (pH 5.0 to 7.4) |
| Lindera benzoin | Spicebush | | Native and Invasive Plants | Shrub 4 to 8 feet, Deciduous, Part shade, Zone 4a, Can tolerate acid to alkaline soil (pH 5.0 to 8.0) |
| Ligustrum obtusifolium | Border Privet | | Native and Invasive Plants | Shrub > 8 feet, Deciduous, Full sun, Part shade, Zone 3a, Can tolerate acid to alkaline soil (pH 5.0 to 8.0) |
| Ligustrum amurense | Amur Privet | | None Listed | Shrub 4 to 8 feet, Deciduous, Full sun, Part shade, Zone 4b |
| Leucothoe fontanesiana | Drooping Leucothoe; Fetterbush; Dog-hobble | | | Shrub < 4 feet, Groundcover, Evergreen, Part shade, Shade, Zone 4b, Requires acid (pH 5.0 to 7.0) |
| Larix laricina | Eastern Larch; American Larch; Tamarack | | Birch, Larch, Magnolias and Nut Trees at Arboretum | Tree > 30 feet, Deciduous, Full sun, Zone 3a, Can tolerate acid to neutral soil (pH 5.0 to 7.4), Tolerates salt spray |
| Larix kaempferi | Japanese Larch | | Birch, Larch, Magnolias and Nut Trees at Arboretum | Tree > 30 feet, Deciduous, Full sun, Zone 4a, Can tolerate acid to neutral soil (pH 5.0 to 7.4) |
| Larix decidua | European Larch; Common Larch | | None Listed | Tree > 30 feet, Deciduous, Full sun, Zone 5a, Can tolerate acid to neutral soil (pH 5.0 to 7.4) |
| Lagerstroemia indica | Crape Myrtle, Crepe Myrtle | | Zone 6 & 7 Plants plus shrubs | Tree < 30 feet, Shrub > 8 feet, Shrub 4 to 8 feet, Deciduous, Full sun, Zone 7a, Can tolerate acid to alkaline soil (pH 5.0 to 8.0) |
| Laburnum x watereri | Goldenchain Tree | | Rosaceous & Flowering Trees | Tree < 30 feet, Deciduous, Full sun, Part shade, Zone 5b, Can tolerate acid to alkaline soil (pH 5.0 to 8.0) |
| Kolkwitzia amabilis | Beautybush | | Spring Flowering Trees and Shrubs | Shrub 4 to 8 feet, Deciduous, Full sun, Zone 5a, Can tolerate acid to alkaline soil (pH 5.0 to 8.0) |
| Koelreuteria paniculata | Golden-rain Tree; Varnish Tree | | Dry Site Plants | Tree < 30 feet, Deciduous, Full sun, Zone 5b, Can tolerate acid to alkaline soil (pH 5.0 to 8.0), Tolerates salty soil |
| Kerria japonica | Japanese Kerria; Kerria Rose | | Spring Flowering Trees and Shrubs, Zone 6 & 7 Plants plus shrubs | Shrub 4 to 8 feet, Deciduous, Part shade, Zone 5b, Can tolerate acid to alkaline soil (pH 5.0 to 8.0) |
| Kalmia latifolia | Mountain Laurel; Mountain-laurel Kalmia | | Broad-leaved Evergreens | Shrub 4 to 8 feet, Evergreen, Part shade, Shade, Zone 5a, Requires acid (pH 5.0 to 7.0) |
| Juniperus virginiana | Eastern Red Cedar | | Evergreens with Scales | Tree < 30 feet, Shrub > 8 feet, Groundcover, Evergreen, Full sun, Zone 3b, Can tolerate acid to alkaline soil (pH 5.0 to 8.0), Tolerates salty soil |
| Juniperus squamata | Singleseed Juniper | | Evergreens with Scales | Shrub 4 to 8 feet, Shrub < 4 feet, Evergreen, Full sun, Zone 4a, Can tolerate acid to alkaline soil (pH 5.0 to 8.0) |
| Juniperus scopulorum | Colorado Red Cedar; Rocky Mountain Juniper | | None Listed | Tree > 30 feet, Tree < 30 feet, Evergreen, Full sun, Zone 3b, Can tolerate acid to alkaline soil (pH 5.0 to 8.0) |
| Juniperus sabina | Savin Juniper | | Evergreens with Scales | Shrub < 4 feet, Groundcover, Evergreen, Full sun, Zone 3b, Can tolerate acid to alkaline soil (pH 5.0 to 8.0), Tolerates salt spray |
| Juniperus rigida | Temple Juniper; Needle Juniper | | | Tree < 30 feet, Evergreen, Full sun, Part shade, Zone 6a, Can tolerate acid to alkaline soil (pH 5.0 to 8.0) |
| Juniperus procumbens | Japanese Garden Juniper; Japgarden Juniper | | Evergreens with Scales | Shrub < 4 feet, Groundcover, Evergreen, Full sun, Zone 5a, Can tolerate acid to alkaline soil (pH 5.0 to 8.0) |