What are USDA Plant Hardiness Zones
The United States Department of Agriculture (USDA) established 13 Plant Hardiness Zones in 2012 to help gardeners and growers determine which plants grow best in different areas.
The map shows 26 options, because each of the plant hardiness zones is broken into two (a and b), based on average annual minimum winter temperatures. Zone 1, with the coldest temperatures, is found in northern Alaska, while Zone 13, with the mildest temperatures, is found in the southernmost parts of Florida and Hawaii. The subzones (a and b) represent 5°F differences within the main plant hardiness zones. For example, Zone 8a has a slightly colder average annual minimum temperature than Zone 8b.
Gardeners and growers use this “plant hardiness zones” information to choose plants that can survive and thrive in their specific zone. For instance, if you live in Zone 6, you would typically select plants that are recommended for Zone 6 or colder, as they are better adapted to the local winter temperatures.
You can download the map and print it out if you wish. But the map is interactive and you can extract a lot of information from it online. Even if you don’t live in the U.S., you can make use of the map, provided you know what the average minimum temperature is where you live.
In this article, we’re going to focus on shrubs that grow in different USDA plant hardiness zones. While most shrubs will tolerate a range of temperature zones, we’ve picked out some examples to show specific suitability.
Just be aware that the USDA Plant Hardiness Zones are not the only factor to consider when selecting plants. Other factors like soil type, sunlight exposure, and moisture levels also play critical roles in determining a plant’s success. Additionally, microclimates within a region can exist, which may deviate slightly from the overall zone classification.
Suitable Shrubs for the 13 USDA Plant Hardiness Zones
Please note that the average minimum temperatures are provided next to each plant hardiness
Zone 1: -60°F to -50°F / -51°C to -46°C
Plant Suggestion: Arctic Willow (Salix arctica)
This small shrub is well-adapted to extreme cold and is found in the far northern regions of North America. It has attractive silvery-gray foliage and can withstand the harsh conditions of Zone 1.
Zone 2: -50°F to -40°F / -46°C to -40°C
Plant Suggestion: Siberian Dogwood (Cornus alba ‘Sibirica’)
This deciduous shrub is known for its striking red stems in winter, adding visual interest to the landscape. It is hardy enough to endure the cold temperatures of Zone 2.
Zone 3: -40°F to -30°F / -40°C to -34°C
Plant Suggestion: Common Lilac (Syringa vulgaris)
Lilacs are beloved for their fragrant flowers in spring. They are cold-hardy and thrive in Zone 3, bringing beauty and aroma to gardens.
Zone 4: -30°F to -20°F / -34°C to -29°C
Plant Suggestion: Ninebark (Physocarpus opulifolius)
Ninebark is a versatile shrub with attractive peeling bark and clusters of small white or pink flowers. It is well-suited for the cold temperatures of Zone 4.
Zone 5: -20°F to -10°F / -29°C to -23°C
Plant Suggestion: Redosier Dogwood (Cornus sericea)
This hardy shrub displays bright red stems in winter and produces clusters of white flowers in spring. It thrives in the milder cold of Zone 5.
Zone 6: -10°F to 0°F / -23°C to -18°C
Plant Suggestion: Butterfly Bush (Buddleja davidii)
This fast-growing shrub is loved for its fragrant, colorful flower spikes that attract butterflies and other pollinators. It is well-suited for the milder winters of Zone 6.
Zone 7: 0°F to 10°F / -18°C to -12°C
Plant Suggestion: Camellia (Camellia japonica)
Camellias are evergreen shrubs with beautiful, glossy foliage and stunning flowers that bloom in late winter and early spring. They thrive in the temperate conditions of Zone 7.
Zone 8: 10°F to 20°F / -12°C to -7°C
Plant Suggestion: Azalea (Rhododendron spp.)
Azaleas are popular for their vibrant, showy flowers and lush foliage. They prefer the mild winters of Zone 8 and add a splash of color to gardens in spring.
Zone 9: 20°F to 30°F / -7°C to -1°C
Plant Suggestion: Bougainvillea (Bougainvillea spp.)
This tropical shrub is famous for its brilliant, papery bracts that come in various colors. It thrives in the warm temperatures of Zone 9 and is an excellent choice for adding a tropical touch to landscapes.
Zone 10: 30°F to 40°F / -1°C to 4°C
Plant Suggestion: Canna Lily (Canna indica)
Canna lilies are vibrant and colorful tropical plants known for their large, broad leaves and striking flowers. They come in various colors like red, orange, yellow, and pink. Canna lilies thrive in the warm temperatures of Zone 10 and can add a touch of the exotic to gardens and landscapes.
Canna lilies are often used to create stunning focal points in gardens or as border plants due to their tall and elegant growth habit. They are relatively low maintenance and can bring a tropical flair to any outdoor space in Zone 10.
Zone 11: 40°F to 50°F / 4°C to 10°C
Plant Suggestion: Bird of Paradise (Strelitzia reginae)
Bird of Paradise is an exotic shrub with striking, bird-like orange and blue flowers. It flourishes in the tropical conditions of Zone 11 and adds a dramatic touch to gardens.
Zone 12: 50°F to 60°F / 10°C to 16°C
Plant Suggestion: Frangipani (Plumeria spp.)
Frangipani, also known as Plumeria, is a stunning tropical shrub or small tree famous for its sweet-scented, colorful flowers. It thrives in the warm and tropical conditions of Zone 12 and is commonly found in places with balmy climates.
Frangipani flowers come in a variety of colors, such as white, yellow, pink, and red, and they add a lovely and exotic touch to gardens or landscapes. With their beauty and fragrance, Frangipani is a perfect addition to tropical and subtropical gardens in Zone 12.
Zone 13: Above 60°F / 16°C
Plant Suggestion: Hibiscus (Hibiscus rosa-sinensis)
Hibiscus is a tropical shrub with large, showy flowers that come in various colors. It loves the hot climate of Zone 13 and is a favorite for adding a splash of color to landscapes.
In the warmer plant hardiness zones, a wide variety of tropical and subtropical plants thrive, including palms, succulents, and many other colorful flowering plants. Always consider the specific conditions in your local area, such as humidity levels, rainfall, and soil types, to choose the best plants for your garden or landscape.
Enjoy creating a lush and beautiful outdoor space!
Tip to Remember
While the shrubs we have suggested are generally suited to the respective plant hardiness
zones, other factors like soil, sunlight, and moisture levels must also be taken into account for successful growth. Gardening in different USDA Plant Hardiness Zones offers a wide variety of plant options, and it’s always exciting to explore the diverse plant life that can thrive in each region.
It’s also a good idea to consult with local gardening experts or extension services to get more specific and tailored advice for your area. Happy gardening!