Mahonia aquifolium is a glossy evergreen shrub native to the Pacific Northwest. It features pinnate leaves on long, irregular stems. The individual leaves are leathery, spiny, and resemble holly. The shrub is somewhat coarse in habit, but is still an interesting and ornamental addition to a cold hardy tropical garden. It will eventually reach 8 feet in height, and will spread out via suckers to reach 3-5 feet in diameter.

It is known as the Oregon Grape Holly due to the bluish-black berries it forms from late summer through autumn, which resemble grapes.

Mahonia aquifolium is hardy to Zone 5, and tolerates a wide range of growing conditions. It prefers rich organic soil but is very adaptable. It can grow in full sun to full shade, in well-drained soil or clay, and tolerates seasonal flooding.

The chocolate vine is deciduous in cold climates, but can be semi-evergreen to evergreen in warmer areas. It is a good choice for a vertical foliage accent in moderately shaded locations.

Sasa palmata is one of the largest-leaved bamboos of genus Sasa. Its common name is the palm-leaved bamboo, and it is widely grown for its tropical effect, with vibrant green, palm-like leaves that can grow up to 15 inches long and 3-4 inches wide. It is potentially a very invasive runner, so it is best grown with a root barrier or in a container.

It eventually reaches a maximum height of about 7 feet, with a maximum culm diameter of 1/4″.

Hardiness

Sasa palmata is rated hardy to -5°F (zone 6b), but it may survive temperatures up to 10 degrees colder, especially if the ground is well mulched. As long as the root/rhizome system survives, it will send up new growth in the spring, even if the plant is completely top-killed.

Musella lasiocarpa is a great plant for a tropical effect in cooler climate zones. It is not a true banana, but a banana relative, and has a smaller, shrub-like form. It can produce a large, lotus-shaped, waxy yellow flower that will remain in bloom for six months.

The Chinese yellow banana is endemic to the Yunnan province of China, and it grows in mountains up to 2500 meters in altitude. Its flower is known as the Golden Lotus Flower, a sacred flower in local Buddhism.

It will eventually form a large clump, up to 15 feet in diameter and 5 feet high.

Hardiness

The Chinese yellow banana is considered root-hardy to zone 6. Plants resist light frost but die back at 28° F.

Winter Protection

Cut back leaves after soon after light frost damage occurs. Spray the root crown with a fungicide to prevent fungal rot during the winter. Use heavy mulch around the root crown to protect from freezing. Gradually remove the mulch in late winter-early spring as the risk of a hard freeze passes.

Growing Tips

Grow in full sun to partial shade. Musella lasiocarpa prefers even moisture throughout the growing season. Leaves may be shredded or dried out in a windy location; pick a site with some wind protection.

Hardy to Zone 7, its bulbs can be stored indoors in winter in colder climates. ‘Tropicanna’ grows best in full sun, and requires frequent watering in the summer to attain its full size and best coloration.

This canna is of South African origin. It was introduced by Anthony Tesselaar, and is patent protected. He has stated that similar cannas are currently in development:

“We were very excited about Tropicanna, as it was a whole new color and direction in cannas. The distinctive foliage brought a new excitement into these plants. There is nothing nicer than when the sun shines through from behind the leaf and allows the colors to radiate. Yes, we are happy to say that we now have another similar canna, but a different color, coming through that will also be of the same tropical look and be a real addition to the Tropicanna group.”

About Nandina Domestica

Nandina domestica, or heavenly bamboo, is completely unrelated to bamboo. Its name comes from its fine, bamboo-like foliage and its cane-like stems. It is an evergreen to deciduous shrub that will grow to 5 feet tall , 3 feet wide, at a moderate rate. Some sources list Nandina domestica as hardy only to zone 7, but it is hardy to zone 6 with some dieback. It will lose its leaves at 10°F, and at -10°F, its stems will die back to the ground. Recovery is quick in the spring.

Nandina domestica ‘Monum’ / Plum Passion® (Heavenly bamboo). The colorful, finely-textured foliage creates a striking contrast with big-leaved background plants like Musella lasiocarpa.

Many named cultivars of heavenly bamboo exist, each with different variations in color. Many nandinas feature tropical-looking leaf color combinations of brilliant reds, bronzes, and greens, as well as bright red color in the fall. Some cultivars recently offered by Monrovia have notably superior foliage color. They include ‘Monum’ (Plum Passion®), ‘Monfar’ (Sienna Sunrise™), and ‘Firepower’.

Nandina domestica may be grown in partial shade, but the foliage colors will be much more intense if it is grown in sun. It prefers a moist, somewhat rich, acidic soil. Once established, it becomes very adaptable and will tolerate a wide range of conditions. Site the plant to protect it from harsh winds.

Camellias are evergreen shrubs or small trees with attractive glossy foliage. They originate from subtropical regions of China, Japan and neighboring countries. They are known for their dramatic blooms during the off-season - autumn, winter, or early spring, depending on the cultivar and climate.

Typically, camellias have been grown only in the southern United States, but more recently, the development of cold-hardy cultivars has extended their potential growing range considerably.

Hardiness

Several camellia cultivars have been developed that are hardy to zone 6. A select few, such as those developed by Dr. William Ackerman at the National Arboretum, are hardy to -15°F, and may be worth trying in zone 5.

Camellia ‘Snow Flurry’

The Hardiest Camellias

• Camellia japonica
  A spring-blooming camellia. Cultivars hardy to zone 6b: “April Series” (’April Dawn’, ‘April Kiss’, ‘April Blush’, etc.), ‘Betty Sette’, ‘Frost Queen’, ‘Jerry Hill’, ‘Pink Icicle’, ‘Red Aurora’, ‘Red Jade’, ‘Spring’s Promise’, ‘Bernice Boddie’.
• Camellia oleifera
  Tea-oil camellia, hardy to zone 6. Often used to hybridize with camellias with showier flowers.
• Camellia oleifera Hybrids
  Ackerman Hybrids
  Developed by Dr. William Ackerman at the U.S. National Arboretum in Washington, D.C. Hardy to zone 6, some selections possibly to zone 5. Named cultivars: ‘Ashton’s Pride’, ‘Frost Prince’, ‘Lushan Snow’, ‘Pink Icicle’, ‘Polar Ice’, ‘Snow Flurry’, “Winter Series” (’Winter’s Beauty’, ‘Winter’s Charm’, ‘Winter’s Dream’, etc.).
• Camellia Forest Hybrids
  Developed by Camellia Forest, hardy to zone 6. Named cultivars: ‘Mason Farm’, ‘Survivor’, ‘Twilight Glow’.
• Camellia sinensis var. sinensis
  A small-leaf tea camellia, hardy to zone 6. Originally grown from seeds collected in Korea where it was growing in the wild; it had probably escaped from cultivation. This variety is vigorous and grows as a shrub, 6 to 8 ft. tall.

Winter Protection

Site camellias to protect from cold, drying winds. Make sure the plant is heavily mulched around the base; small plants can be completely covered with a loose, non-compacting mulch. Application of an antidessicant spray such as Wilt-Pruf® will reduce moisture loss during the winter.

Growing Tips

Camellias prefer light shade when young. Growing in well-drained, organic soils is essential. Camellias prefer slightly acidic soil, but do not amend the soil to be too acidic or overfertilized.

Musa basjoo is generally considered the most cold-hardy banana.

While it does grow in Japan, the Japanese fiber banana is native to the Ryukyu Archipelago, which lies between Japan and Taiwan. It is also very common in parts of China.

Its large, tropical foliage and fast growth rate make it ideal for a dramatic feature in the tropicalesque garden. It will eventually form a large, deep green clump, up to at least 18 feet tall.

Hardiness

Musa basjoo is somewhat unique in that it will actively grow in cool weather. The banana will continue growing until temperatures reach approximately 40° F. It will resist light frost, but die back at 28° F. It is is considered root-hardy to zone 6, and will survive a zone 5 winter with heavy mulch.

Winter Protection

Cut back leaves after soon after light frost damage occurs. Spray the root crown with a fungicide to prevent fungal rot during the winter. Use heavy mulch around the root crown to protect from freezing. Gradually remove the mulch in late winter-early spring as the risk of a hard freeze passes.

Growing Tips

Grow in full sun to partial shade. Musa basjoo thrives on plenty of fertilizer and water during the growing season. It will do well with a regular application of balanced liquid fertilizer applied weekly during the summer. While it is a heavy feeder, be careful not to burn the plant with too high a concentration of fertilizer. Top-dressing with composted manure is another popular feeding method. Leaves may be shredded or dried out in a windy location; pick a site with some wind protection.

About Trachycarpus Fortunei

Windmill palms (a.k.a. Chusan Palms) are native to a large region of southeastern Asia, ranging from India to China, and are found in mountainous elevations above 6,500 feet. They can face extended periods of below-freezing weather as well as heavy snow in their native habitats.

All members of the trachycarpus genus share some common characteristics, such as a tall, narrow trunk, and a compact crown featuring a dense group of palmate leaves. The old, dead leaves can form a skirt around the top of the trunk. They often grow up to 30 feet when planted in warmer temperate regions of the United States, and can grow even taller in their native habitat.

Hardiness

One notable characteristic of trachycarpus fortunei is that it prefers mild summers. In fact, it will not grow in hot, tropical areas, but it seems to grow well throughout most of the southern United States, and up the west coast as far north as Vancouver.

Windmill palms can be grown to zone 7b without significant winter protection. In a sheltered site or with winter protection, windmill palms can be grown through zone 6, although defoliation may occur during cold winters. With care, the palms will usually recover from defoliation. The sensitivity of trachycarpus fortunei to defoliation may decrease as the palm becomes older and more established.

Winter Protection

Mulch heavily. Gradually remove the mulch in spring. Site in a favorable wind-protected exposure, such as the south side of a wall or building. Windmill palms are prone to fungal and bacterial crown rot under wet winter conditions. Spraying the foliage and crowns several times during the winter with a fungicide/bactericide spray will help prevent crown rot.

Growing Tips

Windmill palms prefer moist, well-drained, organic soil. Planting in partial shade is recommended, especially in areas with hot summers.

About Sabal Minor

Sabal minor, the dwarf palmetto, is native to the United States, and is considered to be almost as hardy as the needle palm. It grows naturally in the southeastern United States, and its natural habitat extends west to Texas and Oklahoma. Sabal Minor will eventually form a clump about 5-6 feet in height. It grows from a single trunk, which typically grows mostly underground. The presence of a short above-ground trunk may indicate that the plant is actually Sabal ‘Louisiana’, which may be a Sabal minor variety or a closely-related species.

Dwarf palmetto (Sabal minor)
Larry Allain @ USDA-NRCS PLANTS Database

Hardiness

Sabal minor can be very slow to establish, and this can present some problems with hardiness. For the first few years, it grows a set of juvenile strap leaves, which can be damaged by temperatures below 0°F. Damaged juvenile leaves can be very slow to regrow. It is worth protecting through the first few years, however, because established dwarf palmettos should be hardy throughout zone 6. Like needle palms, they have some tolerance to cold, wet winters. An established underground Sabal minor trunk should be able to withstand brief temperature dips below -10°F and regrow damaged or defoliated leaves. One of the hardiest known dwarf palmetto ecotypes is ‘McCurtain County’, native to southeastern Oklahoma. It has been known to survive temperatures as low as -24°F.

Winter Protection

Mulch heavily around the base, but do not completely cover the leaves. Gradually remove the mulch in spring. Site in a favorable wind-protected exposure, such as the south side of a wall or building. Provide some winter shade if possible.

Growing Tips

Dwarf palmettos prefer full sun to light shade. In colder, marginal climates, full sun is better; in hot climates, light shade is preferred. Sabal minor may grow very slowly during a mild summer. It requires the hot, humid conditions of the southeastern United States to see significant growth in a season. Mulch plants and water regularly until well-established.