About Jessica
Jessica Mercer, PhD, is the Senior Horticulturist at Plant Addicts, where she researches, writes, edits, and reviews horticultural content for home gardeners. Since joining Plant Addicts in February 2022, she has worked across shrubs, perennials, annuals, ornamental grasses, trees, houseplants, containers, and other landscape plants.
Jessica combines PhD-level scientific research training with hands-on gardening experience in the Northeast and Pacific Northwest. She has grown hundreds of woody and herbaceous plants and has practical experience with plant selection, pruning, propagation, seasonal maintenance, plant health troubleshooting, native and pollinator plantings, shade gardening, rock gardens, dwarf conifers, ornamental grasses, and four-season containers.
Jessica approaches horticulture as a process of observation, experimentation, and evidence-based problem solving. She studies how plant physiology, dormancy, propagation requirements, soil conditions, climate, water availability, pest pressure, and species-specific adaptations affect plant performance. Her doctoral training helps her evaluate university Extension guidance, horticultural research, breeder information, and cultivar-specific data, then test those recommendations against real growing conditions. She is especially interested in the differences between species and cultivars that explain why a technique succeeds with one plant and fails with another.
Jessica's gardening advice has been featured in Martha Stewart, Apartment Therapy, Homes & Gardens, House Beautiful, Real Homes, Livingetc, and other national home and garden publications.
Education and Horticultural Training
Doctor of Philosophy, Experimental Neuroscience
University of Nebraska Medical Center, Omaha, Nebraska
Bachelor of Arts, Psychology
St. Olaf College, Northfield, Minnesota
HORT 102: Horticulture Plant Science
Edmonds College
Selected horticultural seminars and workshops: Winter Pruning; Four Seasons of Color; Waterwise Trees & Shrubs; Landscaping with Natives; Perennial Vegetables; Pollinator Gardening; Rain Gardens; Ornamental Grasses.
Expertise
Hands-On Horticultural Experience
Jessica has developed and maintained intensive residential gardens in both the Pacific Northwest and Northeast since 2016, working with hundreds of shrubs, perennials, ornamental grasses, conifers, shade plants, alpine and rock-garden plants, trees, bulbs, annuals, edibles, and container plants. Her projects have included converting a steep Seattle slope of roughly 30% grade into a terraced rock garden using locally sourced stone, installing approximately 500 individual drip emitters for summer irrigation, improving lean scree-like soil with locally sourced organic amendments, building raised vegetable beds, and creating tropical-style, woodland, native bird, and native pollinator gardens.
Propagation is a particular area of hands-on interest. Jessica has rooted dozens of uncommon plants from cuttings and grown specialized species from seed using techniques such as warm and cold stratification, scarification, pre-soaking, controlled-temperature germination, and staged dormancy treatments. She has used these methods with challenging genera including Actaea, Alstroemeria, Dierama, Echinacea, Pediomelum, Penstemon, Salvia, Thalictrum, and Trollius.
On her two-acre Connecticut property, Jessica has removed extensive populations of invasive Japanese barberry, Asian bittersweet, tree of heaven, burning bush, and other invasive plants and replaced them with native woodland trees, shrubs, and perennials. She has converted lawn to native and ornamental planting beds with sheet mulching, created habitat plantings for birds and pollinators, and trialed deer-resistant plants, repellents, and other protection strategies under heavy browsing pressure. She has also installed stone and wood pathways to improve garden access and applies landscape-design principles such as contrast in texture, height, form, and repetition when developing plant combinations.
Favorite Plants
Salvias are an all-time favorite because this large genus includes many dependable plants with long bloom seasons and excellent pollinator value. Many perennial types handle summer heat well and keep flowering when grown in the right conditions.
Ornamental grasses are another favorite. Their upright, arching, or mounded forms add movement and texture to mixed borders, and repeating grasses throughout a planting can create continuity between groups of flowering plants. Jessica also enjoys Japanese maples for their branching structure, foliage, fall color, and the skill involved in selective pruning.
Featured Gardening Guides
Jessica researches Plant Addicts buying guides and gardening resources that help gardeners compare plants by climate, light, mature size, maintenance needs, and landscape use.
Best Low-Maintenance Shrubs For Front Of House
Choosing appropriately sized shrubs for foundations, windows, entry gardens, and front-yard beds.
Best Low-Maintenance Evergreen Shrubs
Evergreen structure, compact choices, privacy plants, and site-based shrub selection.
Best Flowering Shrubs For Full Sun
Flowering shrubs for sunny landscapes compared by mature size, bloom, climate, and garden role.
Best Low-Maintenance Shrubs For Shade
Lower-light shrubs selected with structure, mature size, flowering, and long-term maintenance in mind.
Best Deer-Resistant Perennials For Full Sun
Plant selection that considers deer resistance alongside climate, light, size, and garden performance.
New Gardening Trends 2026
Emerging ideas in plant selection, ecological gardening, garden design, containers, and home horticulture.
More recent guides: Best Fall Plants Other Than Mums, Best Flowering Shrubs For Shade, Long-Blooming Shade Perennials, Best Deer-Resistant Perennials For Shade, Low-Maintenance Plants For Shade, and Best Pet-Safe Low-Light Houseplants.
Popular Plant Care Guides
Planting Geraniums
How to site, plant, and establish geraniums for healthy growth and flowering.
Growing Agapanthus In Pots
Container sizing, planting, light, watering, and care for potted agapanthus.
Fountain Grass Care
Light, watering, pruning, seasonal maintenance, and growing fountain grass successfully.
Japanese Forest Grass Care
Growing and maintaining Hakone grass in shaded and partially shaded landscapes.
Jessica's Gardening Advice In The Media
Jessica is regularly interviewed by home, garden, and lifestyle publications about plant care, garden design, propagation, seasonal gardening, shrubs, perennials, containers, and plant troubleshooting.
Spring Gardening Tips
Soil preparation and establishing bare-root plants.
Easy Design Tweaks For A Professionally Styled Garden
Plant layering, mature size, color combinations, proportion, and cohesive planting design.
Best Outdoor Hanging Plants
Container plant selection, foliage combinations, and outdoor light requirements.
Tomato Companion Plants
Companion planting, plant interactions, pollinator support, and garden ecology.
How To Care For Hydrangeas
Planting timing, frost considerations, and adapting hydrangea care to climate.
How To Propagate Coleus
Stem cuttings, rooting media, humidity, node placement, and light during propagation.
Jessica's horticultural commentary has also appeared in Martha Stewart, Homes & Gardens, Apartment Therapy, House Beautiful, Real Homes, Livingetc, Real Simple, Better Homes & Gardens, Sunset, NBC News Select, and other home and garden publications.
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