USDA Plant Hardiness Zone 10
USDA Plant Hardiness Zone 10 covers a much narrower geographical region than most other growing zones and is characterized by hot summers and mild winters. The average winter low temperatures are between 30 and 40 degrees F, so freezing temperatures are typically not prohibitive to growing many plants in this zone. At the other end of the temperature spectrum, high heat presents a challenge for growing some plants in this region. Pockets of cities contained in Zone 9 include San Francisco, San Diego, Los Angeles and Miami.
Featured by plant type, here are some stellar performers in Zone 10:
Trees
Because of its long growing season, Zone 10 supports trees that cover a diverse spectrum, including palms, needled evergreens, broadleaf specimens and flowering trees:
• Sago Palm (Cycas revoluta) – potted on the patio or planted in-ground, versatile sago palm can also be grown as a houseplant
• Italian Cypress (Cupressus sempervirens) – forms a tall and slender evergreen backdrop for framing a formal garden or defining your property borders
• Eucalyptus (Eucalyptus cinerea) – fragrant evergreen with striking silvery-blue leaves
• Little Gem Magnolia (Magnolia grandiflora 'Little Gem') – glossy, evergreen leaves and large white flowers on a scaled-down version of the Southern Magnolia
• Muscogee Crape Myrtle (Lagerstroemia indica x fauriei 'Muscogee') – a heat-loving alternative to lilacs, this crape myrtle has lavender flowers
• Royal Empress (Paulownia elongata) – a sterile, non-invasive tree with magnificent lavender flowers
Shrubs
Choose shrubs of various sizes and shapes that have different leaf and flower types to add fullness and year-round interest to your garden:
• Waxmyrtle (Morella cerifera, formerly M. cerifera) – fragrant leaves and attractive to birds because of the berries it produces
• Variegated Privet (Ligustrum sinense 'Variegata') – two-toned leaves of green and cream break up the monotony of solid-green shrubs
• Encore Azaleas (Rhododendron spp.) – flower colors include white, pink, red, coral and purple on plants that are repeat bloomers
• Kramers Supreme Camellia (Camellia japonica 'Kramers Supreme') – fragrant peony-form red blooms
• Tea Camellia (Camellia sinensis) – this is the white-flowering camellia species used to make tea
• Frost Proof Gardenia (Gardenia jasminoides 'Frost Proof') – fragrant white flowers cover shrubs with glossy-green leaves
• Radicans Gardenia (Gardenia jasminoides 'Radicans') – a dwarf gardenia selection for smaller gardens, with a mature height of only 12-24 inches
Roses
The heat in Zone 10 is tough on many types of roses, but these two types of roses are tough enough to handle the high temperatures without sacrificing bloom quality:
• Drift Roses (Rosa x 'Drift') – shorter, spreading roses that carpet the ground as a continuously blooming groundcover
• Knock Out Rose (Rosa x Knock Out®) – you won't have to deadhead these shrubs to keep them in bloom
Citrus
Although citrus plants must be container-grown indoors during winter in colder zones, gardeners in Zone 10 can easily grow citrus plants outside year-round. Fresh citrus fruits such as these are within arm's reach of a backyard harvest in Zone 10:
• Meyer Lemon (Citrus x meyeri) – a hybrid citrus with a lemony-orange taste
• Key Lime (Citrus aurantiifolia) – heavy fruit set of small, flavorful limes
• Nules Clementine (Citrus clementina 'de Nules') – heavy-bearing and loaded with orange fruits
• Nagami Kumquat (Fortunella margarita 'Nagami') – luscious fruits with edible peel
• Moro Blood Orange (Citrus sinensis 'Moro') – disease-resistant plants that bear fruits with orange peel and red flesh
Fruits
Although citrus is a mainstay in Zone 10, gardeners can also grow other fruits, such as:
• Santa Rosa Plum (Prunus salicina) – a favorite of commercial growers because of consistent plant quality and taste but also easily grown by backyard orchardists
• Brown Turkey Fig (Ficus carica 'Brown Turkey') – classic fig that's stood the test of time; easy to grow and low maintenance
• Loquat (Eriobotrya japonica) – this sub-tropical fruit bears 2-inch fruits with a taste explosion that combines plum and apricot flavors
• Cold-Hardy Avocado (Persea americana 'Mexicola Grande') – each mature tree produces up to 30 pounds of fruit per year and has leaves that are anise-scented
• Dwarf Cavendish Banana (Musa acuminata) – shorter plants make harvesting easier
• Grand Naine Banana (Musa 'Grand Naine') – a large banana plant that is fast-growing and quick to produce fruit