The arboretum has a collection of plants from over 50 countries. Its plant collections now include over 6,000 total taxa of annuals, perennials, bulbs, vines, ground covers, shrubs, and trees, with significant collections of:
Annual Color Trials — an official All-America Selections testing site, evaluating over 700 different annuals and tender perennials each year.
Entry Garden — more than 100 types of tender perennials, mostly tropical.
Finley-Nottingham Rose Garden — over 200 roses representing over 120 taxa, including hybrid teas, hybrid musk roses, David Austin roses, and climbing roses.
Japanese Garden — Japanese plants with a raked-stone Zen garden; plants include Acer palmatum ‘Kiyohime’, Acer palmatum ‘Seiryu’, Chamaecyparis obtusa ‘Nana Gracilis’, Lagerstroemia fauriei, Nandina domestica f. capillaris cultivars, and Pinus taeda ‘Nana’.
Klein-Pringle White Garden — white-flowered plants and plants with gray, white, or silver foliage, inspired by the famous White Garden at Sissinghurst Castle Garden; plants include Acer palmatum, Lagerstroemia ‘Natchez’, Magnolia × loebneri ‘Merrill’, Styrax japonicus ‘Emerald Pagoda’, and Viburnum ‘Mohawk’.
Lath House — over 700 kinds of shade-loving plants, including Acanthus spinosus, Cornus controversa 'Variegata', Farfugium japonicum 'Aureomaculatum', Gentiana saponaria, Hydrangea macrophylla ‘Pia’, Pieris japonica ‘Shojo’, and Trochodendron aralioides.
Mixed Border — a large border planting of trees, shrubs, groundcovers, perennials, and bulbs; plants include Campsis grandiflora 'Morning Calm', Chamaecyparis thyoides 'Rubicon', Clematis 'Betty Corning', Cornus sericea 'Silver and Gold', and Hamamelis × intermedia ‘Jelena’.
Model Gardens — home demonstration gardens.
Paradise Garden — for the senses of sight, sound, taste, touch, and smell; plants include Aloysia triphylla, Corylusavellana ‘Contorta’, Hosta ‘Sum and Substance’, and Ziziphus jujuba ‘Inermis’.
Perennial Border — nearly 1,000 plants in a large border planting , with color scheme based upon a plan by Gertrude Jekyll.
Southall Memorial Garden — a hemlock tree grove, with mixed plantings and an open grassy area for gatherings.
Xeric Garden — plants from Mexico and the American Southwest, including Agave, Dasylirion, Echinocactus, Hesperaloe, Nolina, Opuntia, and Yucca.
Winter Garden — plants at their best in winter, including Cryptomeria, Chamaecyparis, Cornus officinalis 'Kintoki', Edgeworthia chrysantha, Epimedium, Hamamelis, Helleborus × hybridus, Ilex, Iris unguicularis, Prunus mume 'Rose Glow', and Yucca.
