Agave

Agave spp. is one of the most spectacular show stopping plants for the southern landscape with the most common species of this genus being Agave americana, also known as Century Plant, due to its long lifespan. The Agave species is most recognized as being used in tequila. Agave can grow to a height of 4 to 6 feet tall and wide and thrive in zones 8 to 11 with full sun and little water. It is hardy in South Texas, most of central Texas, and can be used in the Dallas area, but may be damaged with extended temperatures below 10 degrees Fahrenheit. Agave americana has bold, broad, and thick leaves that range from green, blue-green, silver-blue, and variegated in color. It can live from 10 to 25 years before producing a flower stalk up to 15 feet tall with magnificent yellow blooms in late spring to early summer. As the plant ages the older foliage begins to gracefully arch downward while the younger leaves stay rigid and upright. After it blooms, the Agave dies but soon is replaced by small offshoots that gather around the base.  Small offshoots will begin at the base of the plant long before it will bloom, and they should be removed regularly to allow the primary plan to maintain a gorgeous shape.

20160625_170013Agave should be used with caution in some landscapes and should be handled with care due to its sharp spines on the tips and margins of the leaves. Despite its sharp features, Agave is often utilized as a focal point in residential and commercial landscapes, and it is best paired with soft and colorful textures to provide bold contrast to its broad leaves and silver to green color. It also can be quite interesting as a container plant, but one should be considerate of the potential size of the plant when selecting a container.

 

Other Varieties:

Agave parryi var. truncate or Artichoke Agave is a dense, blue-gray rosette of wide oval shaped leaves that develop in large clumps. It too has sharp spines on the tips of the leaves in a dark brown to black color. It is a waterwise plant and can serve as an interesting mass planting due to its offshoots. It is 2-4 ft wide with flower spikes 15-20 ft tall appearing after 10-15 years.

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Agave ferdinand-regis or Ferdinand Agave is a slow growing, compact succulent forming a rosette of green to blue green leaves tipped with black spines. The leaves of this agave are accented with white marking which give it a more interesting and geometric coloring. It reached 18” tall and wide and is one of the smaller agaves available.

 

*Warning: This plant does not like wet, soggy soil, and roots will rot in this condition.

 

© HDG Landscape Design, 2016

Artemisia

Artemisia ‘Powis Castle’, or Powis Castle Artemisia, is a medium perennial used in many landscapes both as an accent plant and as a means to break up monotonous greens and soften bright colors. Powis Castle can grow to be 2 to 3 feet tall and twice as wide giving it the ability to make landscape look much fuller.  This particular Artemisia thrives in all of Texas (zones 5b to 9) in full sun to partial shade with average water needs. It is a drought tolerant plant used in xeriscaping and Texas native designs. As with many plants, keep in mind that this plant will stretch in shade conditions (less than 4 hours of direct sun), and the preferred shape (as pictured) is compact and obtainable in full sun conditions.

Powis Castle Artemisia is one of my favorite silver colored perennials and can serve multiple purposes in the landscape. Although Powis Castle has pale yellow inconspicuous flowers it is primarily grown for its fine silvery foliage with a velvety texture. Its dense silver leaves make an excellent border or container plant and serves as a great accent for pops of color. Powis Castle should be cut back occasionally to encourage its attractive mounding habit. It is best paired with other flowering perennials and ornamental grasses where its unique color and texture can stand out. I love to pair it with Salvia, Agapanthus, Esperanza, and Coneflowers.

20150618_174235(0)Other Varieties:

Artemisia stelleriana ‘Silver Brocade’, also known as Dusty Miller, is a perennial or groundcover that can reach 12 inches in height and 15 inches wide. It is more cold hardy than the other Artemisia mentioned and is hardy in zones 3 to 9 and requires full sun. It differs from Powis Castle not only its size but also in its larger leaf size.

 

Artemisia scmidtiana ‘Silver Mound’, or Satiny Wormwood, is a small perennial that can grow to 6 to 12 inches tall and 18 inches wide and is hardy in zones 4 to 9.

© HDG Landscape Design, 2016

Red Yucca – Hesperaloe parviflora

Hesperaloe parviflora, also known as Red Yucca, is a moderately growing perennial often used in Texas native and water wise landscaping.  It is hardy in all of Texas, the south and into the mid-west, from zone 5 to 11, and requires full sun. Red Yucca is an evergreen plant with long slender succulent like leaves and tall rose pink flowering stalks with small cup like flowers all along them. This plant can grow to be 3 to 4 feet tall and wide in the landscape with vertical or draping flower stalks up to 6 feet tall. It is a great residential design plant due to its relatively deer resistant nature, for example deer will most likely eat the red blooms but will spare the unpalatable evergreen foliage. 20150618_174225

Red Yucca is used effectively in rock gardens and as a landscape accent, and I like to pair it with are Agave, Mexican Feather Grass, Sotol, and Lantana. It is best when used with other desert like plants and in Texas native designs because it uses low amounts of water much like many other Texas natives, making them natural pairings. It provides continued interest in the landscape with its almost year round blooms of rose pink to salmon. Even when not in bloom it does not lose its interest due to its long slender leaves that give it a grass like texture without being too fine. It can provide a great focal feature when allowed to fall naturally over a boulder, when placed next to a dry river bed, or looks great when planted in a bed topped with crushed granite.

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In my experience, Red Yucca grows well in part shade or filtered sun if the landscape design does not require blooming. This can be advantageous as Red Yucca seed pods yields upwards of 50 seeds per pod. It is easy to grow Red Yucca from seed, and with enough moisture the seed can grow without soil. In fact, the humidity near the Texas gulf coast provides enough moisture in the air to begin the growth of Red Yucca seeds while they are still in the pod. This makes offspring once dropped even easier to root, so remove seed pods or flower stalks as soon as the flowers are no longer present to avoid additional future maintenance.

 

 

Other Varieties:

Hesperaloe parviflora ‘Perpa’ or Brakelights Red Yucca is a variety of Red yucca that features vibrant brake light red blooms. It is a compact new selection with more prolific flowering and exceptionally long season due to its tendency to not set seed pods. It can reach a height of 2 feet tall and is known to attract hummingbirds due to its cup shaped red flowers that are easier for the birds to get pollen out of and are highly visible.

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Fuyu Persimmon

Diospyros kaki ‘Fuyu’, more often known as Fuyu Persimmon, is a highly sought after variety of Persimmon due to the sweet, non-astringent taste.  You will often find Persimmon fruit to be an astringent variety in most commercial stores. There is a small ripe window for Persimmon, so, if you’ve purchased an astringent variety, then it is likely you have eaten Persimmon too early and with a puckered face. It’s no wonder nurseries carry the Fuju Persimmon tree at a slightly higher cost than other varieties, and if you have had a grocery store mishap as I have, then you will appreciate the higher cost and buy the Fuyu tree anyways.

20160609_171930You can expect this tree to reach anywhere from 10′ to 15’ in height from zones 7-9. The Fuyu is self-fertile like most Persimmon varieties, but it is an excellent pollinator for the Maekawa-Jiro which is not self-fertile.

The fruit of the Fuyu Persimmon contains lower tannin content (the cause of the astringent taste) once the fruit turns from green to orange which allows a larger window of time to eat the fruit (can be eaten even when hard). The Fuyu is known to be a heavy producer with brilliant orange fruit shaped like a slightly flattened tomato from late October through November.

Due to the small ornamental size, edible and colorful value, and the fact that the Fuyu is self-fertile, it is an excellent fruiting tree for small residential properties or gardens with limited space.   Although Loquat is used in zone 9 as a screening hedge, for some color from edible fruit, and large evergreen leaves, the Fuyu can provide similar interest. It has broad leaves, similar fruit coloring as loquat, but has additional added value through fall color in the leaves. The use extends further than a Loquat as the Fuyu tends to be used more as an ornamental tree, and thinning the tree is encouraged to allow for more light and fruiting.

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Lamb’s Ear

If you are looking for a deer resistant, low maintenance and drought tolerant evergreen ground cover (zones 8-10) or perennial (zones 4-7), Lamb’s Ear is the ideal plant for you.  Resembling the down-turned, soft ears of a lamb, Stachys byzantine, commonly called Lamb’s ear, is a low growing, soft textured perennial with fuzzy, greenish-silver leaves. It grows from 6”-8” tall, and spreads to 12”.  Although mostly grown for its foliage, it will produce a spike-like, purplish-pink to white flower in spring and summer.

The best location to plant lamb’s ear is in a spot with part-sun to sun conditions with well-drained soil, but it is also known to handle areas with light shade or filtered sun provided the area also drains well. Lamb’s ear can survive in most soils except wet; it will rot if kept in an area with standing water or if watered too much. If you live in a heavy rain area, then build your beds to drain away from this plant and amend the bed area soil for better drainage.

Lamb’s ear will easily grow in zones 4-10, but in areas with hot and humid summers, such as the San Antonio area, it may turn brown from heat stress if not placed in a location that receives some afternoon shade. Lamb’s ear also will self-sow, and can be propagated by dividing the roots, which should be done every three years to encourage new foliage and to prevent root matting. It can also be sheared if it is becoming leggy.

This versatile perennial can be used as informal edging along a path or flower bed, in groups of three or more, as a container plant and is tolerant to grow just about anywhere. Lamb’s ear’s rich texture and silver color is beautiful when contrasted against darker foliage plants and even boulders in a rock garden.

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Varieties:

The two most used varieties are ‘Helen Von Stein’ and ‘Big Ears’.

‘Helen Von Stein’ variety has the most tolerance to stress from hot and humid summers as mentioned above. It flowers either sporadically or not at all, and does best in zones 5-10. Its silver foliage grows 12”-18” tall and spreads 24” wide.

‘Big Ears’ variety is a bit larger than the average Lamb’s Ear, 10” high and 18”-24” wide and has greenish-gray foliage.

Turk’s Cap

Malvaviscus arboreus, or Turk’s Cap, is a large flowering shrub with a natural tendencys, has a tropical look with large leaves, and flowers resembling a turk’s cap bloom or a closed hibiscus flower. It can grow 6 to 8 feet tall and wide with a wild habit that, when used correctly, can work well in an existing natural setting. It can grow in full sun to partial shade and is hardy in zones 8-11(Central Texas and south). Turk’s Cap is evergreen and blooms red or white from mid-summer to early winter, giving a prolonged interest to the plant.

Turk’s Cap, a Texas Native and Texas Superstar, needs to be used carefully in the landscape, due to its natural habit. It is best for naturalistic or native designs that can grow in mass, allowing its form to show true. It is great along fences where it can grow to its true height and provide an evergreen backdrop to other colorful perennials or annual seasonal color. It can also provide a nice shrub for along windowless walls if you are looking for that natural feel. Planting it behind evergreen shrubs can help to mask its wild appearance if needed but still allow its showy flowers to shine.

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Other Varieties:

Malvaviscus drummondii ‘Big Momma’ is a variety that can survive as far north as Dallas and into southern Oklahoma, and has large eye catching coral red flowers. It is a fast grower to 6 feet tall and attracts butterflies, due to its closed flowers that are difficult for bees to access.

Malvaviscus ‘Pam Puryear’ is a newer hybrid variety with pink flowers. It is more cold hardy than traditional Turk’s Cap and can be grown as an annual north Texas. It grows 4 to 6 feet tall and is hardy as a perennial in central and south Texas, blooming late spring to early fall.

Photo Credit: Kristin Howard

Abelia x grandiflora

Abelia x grandiflora, often called Glossy Abelia, is a multi-stemmed, bush-like shrub with arching branches and studded with small, glossy, deep-green leaves which are evergreen to semi-evergreen.  This fast-growing, dense shrub is best used as a barrier or hedge due to its spreading nature and towering height of 6 feet. From mid-summer to fall, Abelia showcases small, lightly fragrant, bell-shaped blooms in white to light pink.  Considered the hardiest of the Abelia family, it prefers a location that has part shade to full sun and acidic, well-drained soil.

Classified a semi-evergreen hardwood shrub, Glossy Abelia is best propagated by stem cuttings in early spring or late summer. Notwithstanding colder temperatures in areas north of Dallas/ Ft. Worth, it is best used in Zones 7 to 9. Abelia is rated for zone 6, but if it is grown outside the preferred zone, it will need protection from the cold. This is a shrub that can be used both in the Houston and Dallas/ Ft. Worth areas if you are creating a cottage look for your landscape. Its rounded form serves as a barrier and hedge as well as an accent shrub. It is also in the same family as Honeysuckle and very appealing to butterflies. Its hardiness allows it to withstand salt spray from coastal areas, attracts bees, and it is not attractive to deer.

There are many varieties of Abelia, but the more interesting varieties currently used as landscape shrubs in the Houston and Dallas areas include Canyon Creek, Twist of Lime and Kaleidoscope.

 Abelia x grandiflora ‘Canyon Creek’ is very similar to the standard Abelia with the exception of its flowers and leaves. Canyon Creek’s leaves emerge in early spring a coppery rose color, then mature green to yellow green before going back to a deep copper color in the late fall.  While the flowers of this hybrid are primarily white, the sepals (the parts that surround and protect the flower bud) hang on, giving the appearance that the plant has both rose- and white-colored flowers.

Abelia x grandiflora ‘Gretol’ is a striking, dark green and yellow variegated form of Abelia with light pink flowers and is more commonly known as the Twist of Lime Abelia. It grows in hardiness zones 6-10 to a more manageable shrub height of about 4 feet, and it is considered more versatile in its application in the landscape. Twist of Lime Abelia can be used in pots, borders, and masses in the garden, and also serves as a great accent and background hedge.

Abelia Abelia x grandiflora ‘Kaleidoscope’ is the show stopper of all the hybrids, boasting beautiful leaf color and seasonal interest. In early spring, the small leaves emerge on red stems painted in yellow and green and offers red fall and winter color. Kaleidoscope is also the most compact of these hybrids with a height of 3 feet.

Abelia is an enduring, versatile addition to any Texas landscape, bringing low-maintenance seasonal interest nearly all year long.

 

 

Dianella tasmanica

Dianella - HDG Landscape DesignDianella tasmanica, often called Flax Lily or Tasmania Lily, is an evergreen, tropical, ornamental shrub with long, grass like leaves. This plant is not a native of Texas as it originates in Australia, but it is very well suited for USDA hardiness zones 8-11. The fan shaped, strap-like leaves are similar to Iris species and are the most attractive feature of this plant growing 15”-18” tall with a 12” spread.  Although noted for its evergreen foliage, Dianella spp. has seasonal interest as well. In spring it sends up lavender-blue colored flower panicles reaching 1 to 2 feet above the fan shaped foliage. Then, following the flowering in summer, the panicles ripen into attractive, blue to dark purple, berries. Optimal growing conditions for Dianella spp.  are part-sun to shade with well-drained soil. It can tolerate a range of soil pH as long as it is watered and placed in a location providing good air movement. Watch out when planting these around small children or animals, as parts of this plant are poisonous.  Once established this plant can survive drought conditions, needing very little water.

There are many varieties of Dianella spp. with a range of leaf colors. Throughout the world, this plant can vary in leaf color from solid green, variegated with white or yellow or red, to solid burgundy. In Houston the most popular varieties are ‘Variegata’ (yellow & green striped leaf margins) and ‘Silver Streak’ (cream & green striped leaf margins), although the hardiest is the true dark-green form. Flower stalks and color  range from the typical blue to yellow or mauve colored flowers depending on variety chosen.

This plant is slow growing but can be propagated by dividing the underground roots, the rhizomes. It is widely used in the Houston area and looks best paired with brightly colored or tropical flowers in landscape beds, borders or containers. This plant is not as commonly used in the Dallas area and is considered a more tender plant that will die back to the ground once exposed to colder temperatures.  The attractive form is best used in shadier seasonal color beds and in pots that can be protected from the colder weather.

Contributed by Jennifer Cates

Photography by Kristin Howard

Foxtail Fern

Asparagus densiflorus ‘Meyersii,’ commonly known as Foxtail Fern, is not a true fern, but a showy ornamental shrub with arching, lime green, soft, needle-like leaves. Growing 2’-3’ tall and just as wide, this versatile shrub can be used as a “thriller” in containers, in a mass planting or as a striking accent in the landscape. This shrub is slow growing with white, inconspicuous flowers, producing red berries in the fall. Foxtail fern prefers part shade to part sun and does best with a low to moderate watering schedule. In warm, southern coastal climates it can handle full sun. Another great feature of this shrub is it is low maintenance, needing no pruning, and withstanding lots of stress including moderate drought conditions.

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 Like many perennials, Foxtail Fern can be propagated by dividing the roots and replanting.  It is classified as an evergreen perennial shrub in USDA plant hardiness zones 9-11, but in zones 8 and higher, like the Dallas area, it is unable to withstand the freezing temperatures. However, closer to the city area of Houston it is planted in large numbers, without much replacement, due to the micro-climate the city offers. It has been reported to overwinter indoors or in green houses in areas where it will suffer freeze damage, but can go dormant showing needle loss and turning brown.

As mentioned above, the application for Foxtail Fern is versatile. Because of its low maintenance and ability to withstand every stress but freezing temperatures, it can be used in most landscapes. Primarily, Foxtail Fern is used as you would any ornamental grass or low growing Yucca, for a textural change. It can be designed into traditional or contemporary landscapes as well as New Orleans or Mediterranean style. Because it can take more sun than most ferns, if you are looking for a fern-like feel to a sunnier side of your landscape, this is the plant for you.

Foxtail Fern is often confused with its cousin Asparagus densiflorus ‘Sprengeri.’ Commonly called Asparagus fern, it features wispy, lime-green, needle –like foliage, but has a spreading, fast-growing habit and sharp thorns. Its roots are often hard to remove once planted in the landscape and it tends to take over. Due to its aggressive root system, Asparagus Fern is best used in contained environments, like pots on a patio or indoors.

Contributed by Jennifer Cates

Photography by Kristin Howard

Bottlebrush Tree

Callistemon rigidus, otherwise known as the Bottlebrush Tree, is a visually appealing, flowering tree used frequently in Texas landscapes for ornamental interest. It grows between 10 and 12 feet tall and 8 feet wide with small silvery green colored evergreen leaves and vibrant red bottlebrush shaped flowers that appear in the late winter to early summer. The Bottlebrush Tree requires full sun, is drought tolerant, is suitable for xeriscaping, and is hardy mostly in South Texas throughout zones 8 to11, or from central Texas to the Gulf of Mexico.

Using the Bottlebrush Tree as a canopy ornamental tree requires maintenance, and should be pruned lightly into the new wood after it is no longer flowering. I recommend pairing this canopy ornamental with lower levels of Texas Sage, Esperanza, and ornamental grasses for a contrast in flowering colors and textures. Some similar varieties  include ‘Red Cascade’ and ‘Scarlet Torch’.

Other Commonly Used Bottlebrush:

Weeping Bottlebrush (Callistemon viminalis) is a 15 to 30 foot tree with a cold hardiness of zones 9-11. As its name may hint, the foliage falls in weeping tendrils on a wide canopy creating a unique look.

Weeping Bottlebrush

Contribution by Katherine Beckett, ASLA