Plants: L
- Labrador Violet Viola labradorica Creeping perennial
- Lace Cactus Echinocereus reichenbachii Flowering shrub
- Lacy Phacelia Phacelia tanacetifolia Wildflower
- Lady Banks' Rose Rosa banksiae Flowering shrub
- Lady Fern Athyrium filix-femina Fern
- Lady of the Night Brunfelsia americana Flowering shrub
- Lady Tulip Tulipa clusiana
- Lady's Mantle Alchemilla mollis Creeping perennial
- Lamb's Ear Stachys byzantina Creeping perennial
- Lanceleaf Coreopsis Coreopsis lanceolata Wildflower
- Lanceleaf Stonecrop Sedum lanceolatum Creeping perennial
- Lantana Lantana camara Flowering shrub
- Large Beardtongue Penstemon grandiflorus Wildflower
- Large Fothergilla Fothergilla major Flowering shrub
- Large-Flowered Coreopsis Coreopsis grandiflora Garden perennial
- Late Boneset Eupatorium serotinum Garden perennial
- Late Figwort Scrophularia marilandica
- Late Lilac Syringa villosa Flowering shrub
- Late Purple Aster Symphyotrichum patens Wildflower
- Laurustinus Viburnum tinus Flowering shrub
- Lavandin Lavandula × intermedia Flowering shrub
- Lavender Lavandula angustifolia Herb
- Lavender Cotton Santolina chamaecyparissus Creeping perennial
- Leadplant Amorpha canescens Wildflower
- Leatherleaf Fern Rumohra adiantiformis Fern
- Leavenworth's Eryngo Eryngium leavenworthii Wildflower
- Leavenworth's Tickseed Coreopsis leavenworthii Wildflower
- Leek Allium ampeloprasum Allium
- Lemon Citrus limon Tree fruit
- Lemon Balm Melissa officinalis Herb
- Lemon Beebalm Monarda citriodora Herb
- Lemon Bottlebrush Callistemon citrinus Flowering shrub
- Lemon Lily Hemerocallis lilioasphodelus Garden perennial
- Lemon Thyme Thymus × citriodorus Creeping perennial
- Lemon Verbena Aloysia citrodora Herb
- Lemongrass Cymbopogon citratus Herb
- Lenten Rose Helleborus orientalis Garden perennial
- Lentil Lens culinaris Legume
- Leopard Lily Lilium pardalinum Bulb
- Leopard Plant Ligularia dentata Garden perennial
- Leopard's Bane Doronicum orientale Garden perennial
- Lesser Bougainvillea Bougainvillea glabra Flowering shrub
- Lesser Calamint Calamintha nepeta Flowering shrub
- Lettuce Lactuca sativa Leafy
- Lewis Flax Linum lewisii Wildflower
- Lewis' Mock Orange Philadelphus lewisii Flowering shrub
- Lewis' Monkeyflower Mimulus lewisii Wildflower
- Lilac Clematis Clematis patens Vine
- Lilac Sage Salvia verticillata Garden perennial
- Lily Magnolia Magnolia liliiflora Flowering shrub
- Lily of the Nile Agapanthus africanus Wildflower
- Lily of the Valley Convallaria majalis Creeping perennial
- Lima Bean Phaseolus lunatus Legume
- Limber Honeysuckle Lonicera dioica Vine
- Lime Citrus latifolia Tree fruit
- Lindley's Blazingstar Mentzelia lindleyi Wildflower
- Lingonberry Vaccinium vitis-idae Berry
- Lion's Ear Leonotis leonurus Flowering shrub
- Lisianthus Eustoma exaltatum subsp. russellianum
- Lithodora Lithodora diffusa Creeping perennial
- Little Bluestem Schizachyrium scoparium Grass
- Little Brown Jug Hexastylis arifolia Creeping perennial
- Little Sur Manzanita Arctostaphylos edmundsii Creeping perennial
- Littleleaf Linden Tilia cordata Flowering tree
- Live Oak Quercus virginiana Nut
- Livingstone Daisy Dorotheanthus bellidiformis Garden annual
- Loblolly Bay Gordonia lasianthus Flowering tree
- Lobster Claw Heliconia rostrata Garden perennial
- Loebner Magnolia Magnolia × loebneri Flowering tree
- Loganberry Rubus x loganobaccus Berry
- London Pride Saxifraga × urbium Garden perennial
- Longbract Wild Indigo Baptisia bracteata
- Longleaf Speedwell Pseudolysimachion longifolium Garden perennial
- Longsepal Beardtongue Penstemon calycosus Wildflower
- Loquat Eriobotrya japonica Tree fruit
- Lovage Levisticum officinale Herb
- Love-in-a-Mist Nigella damascena Garden annual
- Low Beardtongue Penstemon humilis Wildflower
- Lowbush Blueberry Vaccinium angustifolium Berry
- Lucile's Glory of the Snow Chionodoxa luciliae Bulb
- Lungwort Pulmonaria officinalis Creeping perennial
- Lydia Broom Genista lydia Low shrub
- Lyreleaf Sage Salvia lyrata Creeping perennial