Selecting Plants for Virginia Landscapes: Showy Flowering Shrubs

This publication features small, medium, and large flowering shrubs (five of each category) with photos. All photos are by the author. There are at least eight shrubs from each category noted in a table (without photos) at the end of this publication. All shrubs featured or in the table are landscape worthy and are especially suited to landscapes in Virginia and the Mid-Atlantic States.

Shrubs are important features of a landscape. Shrubs, as woody plants with persistent aboveground shoot systems, serve several key functions in the landscape. Two of the more critical functions are the roles they play in creating architectural spaces and beautifying the landscape. In terms of the architectural function, shrubs serve as the walls, ceilings, and floors of a landscape, thereby creating outdoor spaces or “rooms.” They also serve aesthetic functions via their size, form, texture, and showy plant parts, such as flowers, fruit, foliage, and fragrance.

The goal of this publication is to present small, medium, and large shrubs that have showy flowers. While all woody plants have flowers (or flowerlike structures for gymnosperms), only a subset of these plants has somewhat attractive or very showy flowers. We enjoy the beauty of showy flowers, yet showy flowers exist in nature as advertisements and attractants for insect visitation and subsequent pollination. In contrast, many plants with inconspicuous, “non-showy” flowers are wind-pollinated. Despite their beauty, this publication will not cover roses because the topic of roses merits a separate publication.

Appearance of Flowering Shrubs

A shrub can be appreciated for its overall appearance (with or without flowers) as well as for specific parts, such as flowers. Some shrub species such as Chinese snowball viburnum (Viburnum macrocephalum; fig. 1) are covered in large flowers, creating a major impact when viewed at a distance. Other shrubs such as common sweetshrub (Calycanthus floridus; fig. 2) have fewer flowers and require a close proximity for flowers to be appreciated (fig. 3). Individual flowers may be just as attractive, or even more appealing, as large numbers or clusters of flowers. The choice of the “blanketed” or “close inspection” species depends on the landscape objectives and personal preferences.

Shrub species usually flower in the spring or summer. The flowering time for a species can vary quite a bit in Virginia. For example a shrub that flowers in mid-April in the Norfolk area (on the east coast of Virginia) will bloom two to three weeks later in the mountains of Southwest Virginia. The time of flowering (spring or summer) will dictate when to prune plants, and this aspect will be covered in the Pruning Shrubs section of this publication. The bloom period of most flowering plants is relatively brief, usually about two weeks. However, some species have showy flower buds in advance of the opening of flowers that extend the showy period of flowering. Some species flower for several weeks or throughout the summer. Koreanspice viburnum (Viburnum carlesii ‘Compactum’; fig. 4) and mountain-laurel (Kalmia latifolia; fig. 5) are examples of species that have showy flower buds. Species with a brief but spectacular flowering period, such as border forsythia (Forsythia ×intermedia; fig. 6), are luminaries for a short time and then blend into the landscape for the rest of the year. The length of bloom is mainly controlled by genetics, but excessive heat, drought, or rain can decrease the bloom time. Flower scent can vary from very sweet or pleasant smelling to slightly fragrant to objectionable.

To enhance the multiseasonal appeal of your landscape, select species that flower throughout the spring and summer. Also choose species that have attractive plant features such as fruit, leaves, stem color and bark features, texture, or shape that can provide showiness during nonflowering times.

Shrubs in this publication are hardy (tolerate minimum winter temperatures) in U.S. Department of Agriculture plant hardiness zones 6, 7, and 8, with noted exceptions. Consult the USDA Plant Hardiness Zone Map website if you are not familiar with plant hardiness zones (http://planthardiness.ars.usda.gov/PHZMWeb/).

Functions and Characteristics of Flowering Shrubs

A shrub is a multistem woody plant that is less than 16 feet tall.

Shrub Functions

Shrubs can serve several functions in the landscape.

• For beautification.
• As a specimen, focal, or accent plant in a landscape.
• As a border/hedge to delineate areas of a landscape.
• As foundation plants at the base of a house or other structure.
• As a privacy barrier or to screen views.
• To serve environmental functions such as preventing soil erosion, forming a windbreak, creating shade, or as habitats and food sources for birds, insects, spiders, and other animals.
• To provide food for human consumption.

Shrub Height

Shrub size categories (i.e., small, medium, and large) are convenient designations to characterize the mature height of multistemmed woody plants that can grow to 15 feet tall. In this publication, the following heights are ascribed to these categories:

• Small shrubs are less than 5 feet tall.
• Medium shrubs are 5 to less than 9 feet tall.
• Large shrubs are 9 to 15 feet tall.

Some species are in more than one category. For example, glossy abelia (Abelia ×grandiflora) is typically a medium-size shrub, but under certain growing conditions it can grow to a large shrub size. There are also cultivars of this species that stay under 4 feet tall.

The distinction between a large shrub and small tree is a matter of interpretation. For example, white fringe-tree (Chionanthus virginicus; fig. 7) is a large shrub; however, the lower limbs can be removed to create a small tree form (single or multiple trunk; fig. 8).

Shrub Width

Plant width can vary from narrow to wide and will affect its function in the landscape. A shrub’s size and growth rate are influenced by its species characteristics and environmental conditions.

Genus

A genus is a group of species possessing similar fundamental traits but differing in other lesser characteristics. The genus name is the first name of the two-word Latin scientific name. For example, the scientific name for crapemyrtle is Lagerstroemia indica. The genus term is Lagerstroemia.

Species

A species is a natural group of plants composed of similar individuals of a genus that can produce similar offspring. These offspring can display minor variations in appearance and other aspects. The species name is the first and second name of the two-word Latin scientific name. For crapemyrtle, the species is Lagerstroemia indica (“indica” is the specific epithet).

Cultivars and Clones

The terms “cultivar” and “clone” are synonymous and are a subclassification of a species that are genetically identical to their mother plant. Cultivars and clones have been selected for a specific trait such as height, form, flower, or leaf characteristics. For example, a cultivar of crapemyrtle that has red flowers is ‘Arap-aho’ (Lagerstroemia indica ‘Arapaho’).

There are numerous cultivars that have been selected for a relatively small size. For example, panicle hydrangea (Hydrangea paniculata) is typically a large shrub, but the clone Pinky Winky (‘Dvppinky’) is a compact, medium-sized shrub. Oakleaf hydrangea (Hydrangea quercifolia) is a medium shrub, but the cultivar ‘Pee Wee’ is a compact, small shrub. Border forsythia (Forsythia ×intermedia is a large shrub, yet the clone Gold Tide (‘Courtasol’) is a compact, small shrub.

Shrub Impact

Generally, a shrub with numerous flowers has a greater impact than one with fewer or smaller, less-obvious flowers. Correspondingly, shrubs with a large size or shrubs used in large groupings (massed) have a greater visual impact than a small shrub or shrubs used singly in the landscape. This is especially true when viewing shrubs at a distance or while moving by quickly, as in a vehicle. Massed shrub plantings are often used to impart curb appeal to a landscape and draw attention to buildings, entrances, and other prominent landscape features.

Pruning Shrubs

Pruning may be necessary to control plant height and width, to thin plants that are too dense, to remove dead or diseased branches, or to rejuvenate a plant. In terms of pruning for size control, select a species that has a mature size that does not exceed the volume of the shrub’s intended space; this will alleviate the need for pruning for size control. A common mistake is to plant a large shrub species as a foundation plant (for example, at the foundation of a home, below windows, or near an entryway). Plants in these situations will ultimately outgrow their intended space and have to be pruned. In this case, the correct choice is to select a small to medium shrub. Hence, one should select a species/cultivar that suits the volume (height and width) of available landscape space.

An exception to selecting a species that has a mature height appropriate to a particular area is when shrubs are sheared into hedges or screens. In this case, the annual clipping/shearing will maintain plants at the desired height.

In general, spring flowering shrubs flower on one-year-old stems; thus, flowering occurs on the outermost portions of the plant. Some shrub species, such as lilacs (e.g., Syringa vulgaris) and forsythia (Forsythia ×intermedia), require the removal of the larger, older stems on an annual basis to encourage the production of younger, flowering wood. Pruning out older branches results in the growth of new stems that produce more flowers compared to the amount of flowers produced large, old stems.

The time of pruning is important for flowering shrubs. Spring-flowering shrubs flower on “old wood” (i.e., flower buds that were produced on stems in the year prior to flowering). For example, a rhododendron (Rhododendron spp.) that flowers in spring produced its flower buds about 10 months earlier in the prior summer. Therefore, prune spring-flowering shrubs right after they finish flowering; pruning spring flowering shrubs in the summer, fall, winter, or early spring removes flower buds and result in a poor or lack of flower display that spring.

Summer-flowering shrubs flower on “new wood,” (i.e., flower buds are produced during the spring/summer in the year that the plant bears flowers). For example, a crapemyrtle (Lagerstroemia spp.) that flowers in the summer produced its flower buds in late spring/early summer during the same year. Lightly prune summer-flowering shrubs right after they flower, in some cases to encourage repeat flowering, or in late winter before new growth begins. Time of flower bud produc- tion (old wood/new wood) is noted for the shrubs in this publication.

Small Shrubs (less than 5 feet tall)

Mount Airy Fothergilla – Fothergilla ‘Mount Airy’ (zones 5 to 9)

Mount Airy fothergilla makes quite a show in mid-spring (fig. 9). Its upright branches are covered with very attractive white flowers (fig. 10). Flowers are borne on old wood. This plant also has exceptionally showy, bright, fall-foliage colors composed of mixtures of reds, oranges, yellows, and/or maroons (fig. 11). Plants sucker (produce shoots form the root system) to form large colonies over time. Mount Airy fothergilla tolerates shade but has an absolute requirement for acid soils; alkaline soils result in chlorotic (yellow) foliage and poor health. Mount Airy fothergilla is a hybrid of dwarf fothergilla (Fothergilla gardenia) and large fothergilla (Fothergilla major), whose parents are native to the eastern U.S.

Smooth Hydrangea – Hydrangea arborescens
(zones 4 to 9)

Smooth hydrangea produces showy, 4-inch, white flat-topped flowers (lacecap type; ring of showy sterile florets surrounding the inner circle of less showy fertile flowers) in late spring/early summer that persist for about a month; some cultivars bloom into July (figs.12, 13). There are a few clones that have large (up to 10+ inches wide) globe-shaped (mophead type; sphere of mostly sterile florets) flowers with ‘Annabelle’ (fig. 14) and Incrediball (‘Abetwo’) being some of the more popular forms in the trade. Clones with spherical flowers are quite showy due to the abundance of large-size flowers. One issue with ‘Annabelle,’ and perhaps with other such large-flowered cultivars, is that the weight of flowers topples the stems, resulting in a messy appearance (fig. 15). Some gardeners keep the stems upright with stakes. Incrediball is touted as having thicker stems and being less prone to stem-flopping.

There are pink-flowered, globe-shaped clones in the trade, including Bella Anna (‘PIIHA-I’) and Invincibelle Spirit (‘NCHA1’). The flower display is moderately showy for the lacecap types and very showy for the mophead types.

Plants tolerate and will flower in shade; in zones 7 and higher, afternoon shade is recommended. This species’ overall plant appearance is somewhat coarse and unkempt in the winter dormant season. Since it bears flowers on new wood, you can cut the stems to near ground level in the fall or winter. Native to the eastern U.S.

Bigleaf Hydrangea – Hydrangea macrophylla
(zones 7 (6b) to 9)

Although native to Japan, bigleaf hydrangea is one of the most popular flowering shrubs in the U.S. The reason is obvious: a bigleaf hydrangea laden with large colorful flowers for weeks or months during the summer is a spectacular sight (fig. 16). Similar to the smooth hydrangea, bigleaf hydrangea has two types of very showy flowers: flat-topped flowers (lacecap type; ring of showy sterile florets surrounding an inner circle of less showy fertile flowers; fig. 17) and globe-shaped (mophead or hortensia type; sphere of mostly sterile florets; fig. 18). The choice of these flower types depends on personal preference. Flower type affects the overall plant texture; lacecap flowers confer a fine texture, whereas mophead types convey a bold texture.

Flower colors are pink, mauve, blue, purple, and white. Some cultivars are genetically programmed to have flowers that are either pink or white. Flower color for other cultivars depends on soil pH. While exact soil pH values are difficult to pinpoint, in general, if the soil pH is above 5.5 to 6.0, then flowers will be pink.

If the pH is less than 4.5 to 5.0, flowers will be blue. Purplish flowers may be produced at intermediate pH values. Flower color is influenced by the amount of available aluminum in the soil. Aluminum availability is relatively high in an acidic soil (less than pH 7.0) and relatively low in an alkaline soil (higher than pH 7.0). Thus, a soil with a low pH value will have a considerable amount of available aluminum that can be taken up and turn bigleaf hydrangea flowers blue. A comparable soil with a relatively high pH value will have the same amount of aluminum, but it will not be available for uptake by the roots. The lack of aluminum results in pink flowers. Sulfur, aluminum sulfate, or iron sulfate will acidify the soil and/or add aluminum to the soil. Follow the application recommendations carefully because overapplication can damage plant roots.

Grow bigleaf hydrangea in full sun or in part shade. In zones 7 and higher (from Roanoke, Virginia, to the state’s east coast), they should be grown with afternoon shade. Regardless of zone, this species requires ample moisture. In fact, plants will often wilt during the growing season, even when there is adequate moisture, because leaves lose water faster than the roots can absorb it.

There are hundreds of bigleaf hydrangea cultivars in the trade, however, aside from flower type and color, the principal cultivar selection criteria is cold hardiness. Bigleaf hydrangea is rated as a zone 6 to 9 species; however, the shoot system (leaves, stems, and buds) of many cultivars are not hardy in zone 6 (areas west of Roanoke, Virginia), where average minimum temperatures for zone 6 are zero to minus10 F. In general, temperatures below zero F will kill flower buds as well as well as stems, but new stems may be regenerated from roots the following spring provided that the low winter temperatures did not kill the root system. Flower buds, but not necessarily stems, can be killed in the range of zero to 10 F.

There are some cultivars that flower on new wood. Such cultivars are termed remontant, meaning they flower more than once in a growing season. Remontant cultivars will therefore flower following winters with temperatures that kill pre-existing flower buds and/or stems. A very popular remontant clone in the trade is Endless Summer (‘Bailmer’; fig. 16) but there are several other reblooming cultivars, such as ‘David Ramsey,’ ‘Decatur Blue,’ ‘Penny Mac,’ and clones in the Let’s Dance series. Some of the lacecap types have exquisitely beautiful flowers, such as ‘Frau Reiko’ (fig. 19).

There are hundreds of bigleaf hydrangea cultivars that vary in flower and leaf characteristics, stem strength, hardiness, and mildew resistance. In “Hydrangeas for American Gardens,” Michael A. Dirr, the world’s premier woody plant expert, has a scholarly and comprehensive treatment of bigleaf hydrangea. In this publication, Dirr lists the following cultivars as the most reliable for cold hardiness and flowering: ‘All Summer Beauty,’ ‘Coerulea Lace,’ ‘Decatur Blue,’ ‘Frillibet,’ ‘Geisha Girl,’ ‘Lilacina,’ ‘Mme Emile Mouillère,’ ‘Nikko Blue,’ ‘Souvenir du President Paul Doumer,’ ‘Veitchii,’ and ‘White Wave.’ While generally considered a small shrub (less than 5 feet tall), bigleaf hydrangea can occasionally grow to proportions that relegate it to the medium-size category (5 to 9 feet tall), or in the large size category (9+ feet) for some cultivars under exceptional growing conditions.

Virginia Sweetspire – Itea virginica (zones 5 to 9)

Virginia sweetspire has showy masses of pendulous

5-inch-long white flower spikes in early summer (figs. 20, 21). The slightly fragrant flowers are produced on last year’s growth (old wood). This species has attractive, lustrous foliage that turns a beautiful, long-lasting maroon color in the fall (fig. 22). Virginia sweetspire suckers (produces shoots from root system) and over time the mother plant will produce a colony of stems. This species is a wetland species native to the eastern U.S., but it will do fine with average moisture conditions and is shade-tolerant.

Foliage will be yellowish (chlorotic) and in poor health in alkaline soils due to a lack of available iron in the soil. There are a few cultivars in the trade, with ‘Henry’s Garnet’ being claimed as the best of the bunch for having exemplary plant characteristics (i.e., form, flower, fall color).

Bush Cinquefoil – Potentilla fruticosa (zones 2 to 6 (7))

Native to the northern hemisphere, bush cinquefoil produces 1-inch yellow flowers from June until frost on new wood (fig. 23). There are numerous cultivars with orange-yellow, white, and pink flowers; double-flowered forms are also available. This slow-growing species grows in a mounded form (fig. 24). The flowers are its principal aesthetic characteristic. It will tolerate shade but the best floral display occurs in a full sun exposure. Bush cinquefoil is quite tolerant of dry soils and low temperatures.

Medium Shrubs (5 to less than 9 feet tall)

Summersweet Clethra – Clethra alnifolia
(zones 4 to 9)

Summersweet clethra is cloaked in very sweetly fragrant white flower spikes in midsummer (figs. 25, 26). Flowers are so pleasantly scented that this species could be considered Mother Nature’s perfume. Flowers are borne on 5-inch long bottlebrushlike flower stalks and persist for about a month. Plants flower on new wood. This species suckers readily (produces shoots from the roots), so over time it forms a colony of plants originating from the mother. It tolerates shade and is a wetland species, yet it grows well in most acid soils except for soils that tend to be dry. The species has a natural, informal appearance that may not be suitable for some landscapes. The cultivars ‘Compacta’ and ‘Hummingbird’ have a smaller, compact form and lend themselves to a formal landscape. In addition to plant size/habit, other cultivars have been selected for foliage characteristics, flower size and color (fig. 27), and time of flowering. Native to the eastern U.S.

Oakleaf Hydrangea – Hydrangea quercifolia
(zones 5 to 9)

Oakleaf hydrangea has upright branches, large oaklike leaves (with prominent lobes), and large cone-shaped white flower clusters in early summer (figs. 28, 29). The overall flower effect is quite showy. Plants flower on old wood. There are several cultivars that vary in size (from small to large), compactness, flower (single, double, or maturing to burgundy-pink), and leaf characteristics. Fall foliage color is a red-maroon and can be quite attractive (fig. 30). Stems have bark that peels or exfoliates, which is an attractive feature in winter. Oakleaf hydrangea tolerates shade; however, shade-grown plants tend to have very large leaves and reduced flower production. The large, oaklike leaves impart a coarse/bold texture to the plant. Native to the southeastern U.S.

Mountain-laurel – Kalmia latifolia (zones 4 to 9)

Native to the eastern U.S., mountain-laurel can be a large shrub or a small tree in its natural habitat. However, in landscape situations, this slow-growing species rarely reaches such proportions and is typically a medium shrub. Mountain-laurel is arguably one of the most beautiful U.S. native flowering woody plants for overall effect; its exquisitely beautiful flowers deserve close inspection (figs. 5, 31). The duration and beauty of the flower show in late spring is extended because the flower buds (prior to opening) are also colorful and elegantly beautiful (fig. 32). This species flowers on old wood.

So, why is mountain-laurel not in everyone’s garden? The reason is that the degree of its beauty is matched by the degree of difficulty in having this species thrive in man-made landscapes. There are two main cultural aspects to successfully growing this species: (1) very well-drained, loose acid soil is a must; soils with high amounts of organic matter are ideal and (2) plants also require a part shade exposure in the afternoon, especially in winter. An exception to the part shade requirement is that the author has observed plants doing quite well in full sun in mountain environments where temperature, rainfall, and soils are radically different from environmental conditions typical of most residential settings.

There are numerous mountain-laurel cultivars that vary in flower bud and open flower, size and form, foliage, and leaf spot resistance. An especially beautiful cultivar is ‘Sarah,’ which has red-pink buds that open to pink flowers (fig. 33).

Koreanspice Viburnum – Viburnum carlesii
(zones 5 to 7)

As its namesake suggests, this species is native to Korea and is quite beautiful in flower for about two weeks in midspring. Its flower display is showy from a distance or close up; very fragrant dome-shaped flower clusters blanket the shrub (figs. 4, 34). Each cluster is about 3 inches wide and is composed of numerous white flowers that have an exceptionally spicy-sweet fragrance. This sweet scent is so powerful that it can be detected and enjoyed at quite a distance. The duration of the flower show is extended because flower buds prior to opening are a reddish-pink color (fig. 35). This species flowers on old wood. Koreanspice viburnum is a slow-growing shrub that has few, if any, pest problems. The cultivar ‘Compactum’ has a compact form and is a desirable clone due to its improved form and disease resistance.

Glossy Abelia – Abelia ×grandiflora (zones 6 to 9)

A hybrid of two Chinese species, glossy abelia is a relatively common flowering landscape species whose merits support such widespread popularity. First, this species produces showy 1-inch-long white flowers from June to frost on new wood (figs. 36, 37). Second, sepals (petallike structures just beneath flower petals) turn pinkish in the late summer/early fall and add another color dimension to the flower show (fig. 38). While flowers are showy and numerous, collectively they do not completely blanket the exterior of the plant as in other heavily flowered species. Third, this species has lustrous evergreen foliage in zones 7 and higher; in zone 6 it will be semi-evergreen to deciduous, depending on the minimum winter temperatures. Fourth, numerous cultivars are available that vary in form (compactness), flower (abundance of flowers, fragrance), and foliage (yellow/gold or bronze and other variegations). ‘Rose Creek,’ for example, is a dwarf compact form with abundant flowers (fig. 39). A caution about some of these cultivars is that they will occasionally produce shoots that revert to the species characteristic (e.g., noncompact, nonvarie-gated); remove these branches to maintain the selected characteristics of the cultivar. Lastly, this is a tough shrub that tolerates drought, full sun to part shade, and regular shearing. Its evergreen foliage and pruning tolerance support its use as a hedge.

Large Shrubs (9 feet and taller)

Common Smokebush/Smoketree – Cotinus coggygria (zones 5 to 8)

Smokebush has a very impressive “flower” display starting in late spring and extending into summer. The plant is covered in very showy plumelike clusters (plumes from a purple-leaved cultivar are shown; fig. 40). The reason that “flower” is in quotes is because the showy plumes (fig. 41) are actually filaments associated with flowers that are quite small and incon-spicuous; the flowers/plumes are produced on old wood. Plume color varies with leaf color. Common Smokebush has green leaves and light-tan-colored plumes. There are several purple-leaved cultivars that have purplish colored plumes (fig. 42). There are several cultivars that offer variations in “flower” and leaf characteristics. Golden Spirit (‘Ancot’) has attractive yellow foliage (fig. 43), but in the author’s observations, it has a relatively minor display of plumes. An added bonus to this species is that the fall foliage color can be quite spectacular with orange and purple-red colors (fig. 44). Common smokebush tolerates poor soils and drought; however, the species and some cultivars require pruning because it tends to produce long stems with very few side branches, which gives it a tall and lanky look. Once established, you can periodically hardprune or coppice to about 1 foot above ground level to encourage a more compact, multiple-stemmed plant. Alternatively, you can prune common smokebush to remove its lower branches and leave only about three major stems (trunks) to produce a small tree form, hence the alternate common name of common smoketree. Native to Europe and Asia.

Panicle Hydrangea – Hydrangea paniculata
(zones 3 to 9)

In the garden center trade there are numerous cultivars (30 +) of panicle hydrangea that vary in size, form, and flower characteristics. Flower characteristics include time of flowering (June to September) and flower cluster size (fig. 45). ‘Grandiflora’ is the patriarch of the cultivars, introduced in the 1860s, and is a large shrub/small tree form that is spectacular in flower (fig. 46). This cultivar has been described as overused and coarse, but beauty is in the eye of the beholder. ‘Phantom’ has especially large flower clusters. White flower clusters eventually turn brown and tend to persist on the plant, a feature that is often noted as a liability (fig. 47). This aspect can be interpreted as an attractive feature. On the plus side, panicle hydrangea is relatively easy to grow and is the toughest hydrangea for challenging site conditions. This species flowers on new wood except for the cultivar ‘Praecox,’ the earliest flowering cultivar (early summer); it flowers on old wood (so prune right after flowering and not in late summer or the dormant season). Because most of the cultivars flower on new wood, they produce flowers in the summer, a period when there are relatively few woody plants in flower. A full sun exposure produces the best flower show. Native to Asia.

Crapemyrtle – Lagerstroemia spp. (zones 7 to 9)

The flower display of crapemyrtles is one of the showiest of all flowering shrubs (fig. 48). The reason for this is that (1) flower colors include shades of red, pink, lavender, rose, fuchsia, purple, and white (fig. 49); and (2) flower clusters (up to 8 inches long) can be produced for most of the summer (depending on cultivar). Adding to its appeal are a beautiful form (fig. 50), very handsome bark (some smooth and some exfoliating; shades of white, tan, and cinnamon-brown bark; fig. 51), its tolerance of poor soils and legendary heat and drought tolerance, and showy fall foliage color. Crapemyrtle, minus a few shortcomings, is a superstar in the landscape!

When anyone speaks of crapemyrtle, they are really addressing a very large group of cultivars. There are more than 200 cultivars of crapemyrtles that originated from Lagerstroemia indica, L. fauriei, L. indica × L. fauriei hybrids, and L. indica × L. fauriei × L. limii. Crapemyrtle cultivars vary in height (from 3 feet to 30+ feet tall); form; vigor; hardiness; flower color, duration, and ability to rebloom within a growing season; bark color and texture; disease resistance (powdery mildew and cercospera diseases); form; and foliage color (growing season, burgundy and wine-red; in fall, orange, yellow, or red).

The choice of cultivar depends on the landscape objectives and personal preference. However, there are two main crapemyrtle aspects that must be considered for a successful use of this species — mature size and hardiness. Select a cultivar of the appropriate mature size for a particular landscape space. If a large shrub/small tree crapemyrtle cultivar is planted in a location that can only accommodate a smaller-size plant, then the plant will have to be pruned to reduce its height. Instead of reducing the crown by selectively thinning out the limbs, the crapemyrtle is often topped or reduced to an arbitrary height; this type of wood removal ruins the plant’s natural beautiful form and results in an unsightly cluster of branches emerging at each pruning cut. Topping is so undesirable and yet so commonly practiced that it goes by the colloquial description of “crape murder.”

Crapemyrtles can be pruned to an open, vase-shaped form by removing some of the inner branches. Remember that pruning cuts, especially on branches larger than 1/2 inch in diameter, may encourage the growth of water sprouts (vigorous stem growth) from just below the cut.

Early blooming crapemyrtle cultivars can be encouraged to rebloom (produce a second set of flowers) if spent flowers are removed. This will encourage new stem growth followed by new flower buds; this reblooming practice will mostly occur in southern U.S. areas where the growing season is long enough to permit such stem and flower regrowth.

Crapemyrtle cultivars typically have multiple trunks and the number of trunks can be controlled by pruning. Pruning to develop a particular trunk number should be done when plants are young to avoid the aforementioned proliferation of water sprouts.

The Texas A&M website has a sizable list (with photos) of cultivars with flower color, growth habit, height, mildew resistance, fall color, and exfoliating bark rating (“Characteristics of Crape Myrtle Varieties”; http://aggie-horticulture.tamu.edu/databases/crapemyrtle/). Another good reference is the online “Crapemyrtle Database” by the University of Arkansas Cooperative Extension Service; this site covers size, flower color and period, growth habit, disease resistance, and fall foliage color details for several cultivars (www.uaex. edu/yard-garden/resource-library/crape-myrtle/). The U.S. National Arboretum’s website provides a list-ing of many crapemyrtle cultivars with their specific history, plant description, and hardiness information (“Cultivars and Names of Lagerstroemia”; www.usna.usda.gov/Research/Herbarium/Lagerstroemia/Check-list_A.html). The hardiness information in this site is fairly accurate but can often be difficult to exactly categorize because hardiness is not only related to low temperatures. Clemson University also has a thorough description of numerous cultivars (“Crape-myrtle”; www.clemson.edu/extension/horticulture/ landscape_ornamentals/crapemyrtle/).

The hardiness zone range for crapemyrtle species is 7 to 9. Thus, low temperature damage is a major issue if you live in zone 6 (minimum temperatures range from zero to -10 F) or even in zone 7 (minimum temperatures range from 10 to zero F) in the event of an unusually cold winter. Hardiness can be influenced by factors such as the length of exposure to a low temperature, soil moisture, fall temperatures, how long a plant has been transplanted (establishment period), and fall pruning. Know the historically low temperatures to select a cultivar that tolerates the minimum temperatures for your locality. Native to Asia.

Border Forsythia – Forsythia ×intermedia
(zones 6 to 8)

Despite being quite common in landscapes and chosen for its only showy feature — yellow flowers that last for about two weeks a year border forsythia is a rock star when in bloom (figs. 6, 52). This species is covered in bright yellow flowers (fig. 53) for about two weeks in midspring (produced on old wood) before leaves emerge. This fast-growing species tolerates poor growing conditions. To maximize the flowershow, site forsythia in full and rejuvenate old plants by cutting down all of the stems to near ground level or remove the oldest/largest stems. There are several cultivars that vary in the shade of yellow for flowers, plant size, and compactness. The parents of this hybrid are native to China.

Blackhaw Virburnum – Viburnum prunifolium
(zones 3 to 9)

Blackhaw viburnum is another native of the eastern U.S. that has a relatively showy flower display in midspring (figs. 54, 55). However, when compared to some of the common landscape viburnums, such as bigleaf hydrangea (fig. 16), this species may only be deemed moderately showy. Blackhaw viburnum makes up for this apparent inferiority by its fruit and fall foliage show as well as its tolerance for poor soils and drought. In late summer, about 1/3-inch egg-shaped fruits briefly turn a charming pink color before turning blue-black (fig. 56). While marginally showy dressed in the dark color, they are edible by humans and a favorite of local wildlife. The fall foliage varies from plant to plant and from fair to good with shades of red, maroon, or orange. This stiffly upright growing species is commonly found along roadsides, hillsides, and fencerows throughout the eastern U.S. Despite this ubiquity, it is rarely found in garden centers. You can special order this species through your local nursery professional or from mail order nurseries. The common name, blackhaw, is derived from the color of the fruit and its stiffly branched form that is likened to that of a hawthorn (but is not at all related to a hawthorn).

Other Showy Flowering Shrubs

The following tables list other small, medium, and large shrubs with showy flowers.