Hardiness Zones / 11
Based on the minimum ten-year average winter temperatures, plant hardiness zones maps have been progressively developed, first by the Department of Agriculture (USDA) for the United States and then more or less applied to the rest of the planet. The purpose of these hardiness zones is to identify how well plants will withstand the cold winter temperatures of these zones. The USDA Hardiness Zone Map divides North America into 13 zones of 10°F each, ranging from -60°F (-51°C) to 70°F (21°C). The range of minimum average temperatures for zone 11 is between 40°F and 50°F or +4.4°C and +10°C. If you are planning to buy a shrub, perennial or tree, you need to make sure that this new plant will tolerate year-round conditions in your area. Therefore, to ensure your new acquisition will survive and grow year after year, you will need to compare the hardiness zone of your area with the hardiness zone of your plant (included in most American references books, nursery catalogs and gardening magazines describing plants).
Elegant and fast growing, Adiantum raddianum (Delta Maidenhair) is a tufted evergreen fern with smooth, purplish-black stalks bearing triangular, 3-pinnate, lacy fronds composed of rounded, fan-shaped segments. Emerging light green, they darken with age and can reach 18 in. in length (45 cm). Popular as houseplant, it is long lived if it receives sufficient humidity and is not exposed to drafts.
Among the loveliest of Aeoniums, award-winning 'Sunburst' is an evergreen succulent with large variegated rosettes, 6-8 in. across (15-20 cm), of fleshy, spoon-shaped leaves. Held on long bare stems, the leaves are a delightful combination of creamy yellow and green stripes and are adorned with coppery red tips when exposed to the sun.
A truly captivating Aeonium, award-winning 'Zwartkop' is an evergreen succulent with large rosettes, 6-8 in. across (15-20 cm), of glossy, fleshy, dark burgundy, pointed leaves. If grown in full sun, the foliage of this Aeonium turns almost black, adding incredible drama and interest to the garden or containers.
Aeonium canariense is an impressive evergreen succulent with large velvety rosettes, 6-12 in. across (15-30 cm), of fleshy leaves. Fresh green when grown in part shade, the soft, fuzzy leaves become tinged with reddish pink when exposed to the sun.
A very pretty Aeonium, award-winning 'Kiwi' is an evergreen succulent with small variegated rosettes, 3-5 in. across (7-12 cm), of fleshy, spoon-shaped leaves. Creamy-yellow in their center, the pointed leaves gradually change to soft green towards their edges, which are elegantly adorned with a rose-red ribbon when adequately exposed to the sun.
Mostly native to the Canary Islands off the west coast of North Africa, Aeoniums are fascinating evergreen succulents with irresistible rosettes of fleshy, pinwheel leaves. Attractive when not blooming, they are particularly striking with their bright racemes of small, star-shaped flowers.
Agapanthus 'Bressingham Blue' is a flamboyant African Lily with showy, 4.5 in. (11 cm), rounded clusters of deep amethyst-blue flowers from mid summer to early fall. They rise on stiff, upright stalks atop clumps of beautiful, long, shiny leaves.
Agapanthus 'Donau' is a lovely African Lily with showy rounded clusters of star-shaped, pale-blue flowers adorned with dark-blue central stripes. Blooming from midsummer to fall, the showy flowers, up to 8 in. across (20 cm), rise on stiff, upright stalks atop clumps of beautiful, deciduous, arching, lustrous green leaves.
A very attractive variegated Lily of the Nile, Agapanthus 'Silver Moon' enlivens the summer garden with its brightly stripped silvery-white, strap-shaped leaves. It is topped in summer with abundant rounded clusters of trumpet-shaped, lavender-blue flowers, which rise with majesty on stiff, upright stalks.
Among the hardiest Lilies of the Nile, award-winning Agapanthus 'Headbourne Hybrids' produces large rounded clusters, 3-4 in. wide (7-10 cm), of funnel-shaped flowers in variable shades of light and dark violet-blue.
Agave 'Blue Glow' is a slow-growing evergreen succulent which produces elegant rosettes of blue-green, chalky leaves with finely toothed margins adorned with a golden and red ribbon. A striking beauty which is particularly stunning when backlit with its glowing red and golden margin.
A charming and tiny variegated Agave, 'Cream Spike' is a highly ornamental evergreen succulent with small, solitary, rounded rosettes of blue-green leaves adorned with broad butter-yellow margins and dark brown spines. This Agave variety produces many offsets that can be easily pulled and re-planted elsewhere. It is perfect for small containers.
A magnificent Japanese selection, Agave 'Kissho Kan' is an evergreen, perennial succulent forming a perfectly symmetrical rosette of thick, rigid, soft silver-blue to blue-green leaves. The foliage is adorned with creamy white toothed margins and leaf spines, which emerge yellow, change to pale brown before turning dark reddish-brown. \
Smaller than its giant cousin, Agave americana, 'Mediopicta Alba'(Century Plant) is an evergreen perennial forming splendid rosettes of thick, spiny-edged, gray-green leaves, each with a bright creamy-white central stripe. The fleshy leaves are armed with recurved spines along the edges and a long terminal spine.
Smaller than its giant cousin, Agave americana, 'Mediopicta Aurea'(Century Plant) is an evergreen perennial forming striking rosettes of thick, spiny-edged, gray-green leaves, each with a bright yellow central stripe.