Viburnums -- Shrubs for Three-Season Interest
From a design standpoint, Viburnums are an important genus of plants in the garden for several reasons:
They are also important for their ability to be used in many different cultural situations.
Listed below are the viburnums which will grow well in our area. Some species are in my garden now, others used to be, and still others are on my list of plants to purchase. It's very important to place a plant in the right spot so I've included specific information on the cultural conditions required for each species. The harder-to-find species (acerifolium, alnifolium, bitchiuense, macrocephalum, cassinoides, molle, lantana, lentago, obovatum, x rhytidophylloides, and seiboldii) have not been included. Also, there are some viburnums that are not hardy where we live in Zone 6B of the Department of Agriculture Hardiness Zone Map. They are davidii, japonicum, awabuki, odoratissimum, suspensum, tinus and they are not listed here as well.
Basically, viburnums grow in moist, well-drained soil and in sun. As I have mentioned before, after establishing a viburnum for a year or two, it will take some drought. Usually the plant will tell you by its droopy leaves when it needs water.
Here's the list of viburnum species, followed by the new "must-have" cultivars:
x burkwoodii - Burkwood viburnum is not a species but the result of crossing two different species; therefore, the "x" is shown before its name. Grows to about 10x7ft. Its form or habit is upright and multi-stemmed. Leaves are elliptic, pointed, slightly serrated, and 4in long. Fall leaf color is wine red. The flower buds are pink. It has fragrant, white, snowball-type flowers. Its fruit starts red and then changes to black but usually the plant doesn't produce much fruit. (This is a cross between carlesii and utile; both are listed below.)
x carlcephalum - Fragrant viburnum grows to 10x10ft and its habit is open and loose. Leaves are dark green, broadly oval, wavy, pointed and up to 5in long. Fall leaf color is red purple. Its flower buds are pink. It has fragrant, snowball-type, white flowers up to 6in across. Its fruit starts red then changes to black. (This is a cross between carlesii and macrocephalum var. keteleeri.)
carlesii - Koreanspice viburnum grows to 6x6ft into a dense, rounded shrub. The leaves are a dull, dark green and a wide oval in shape. The leaves are slightly serrated, pointed and are 4in long. Flower buds are pink to red. Its fragrant, semi-snowball, white flowers are 3in wide. Fruit starts red and then changes to black.
dentatum - Arrowwood viburnum is a native shrub occurring naturally in eastern North America. Grows to 10x10ft in a dense, rounded form. Its leaves are a lustrous dark green, broadly oval in shape and pointed. The leaf's margins are coarsely serrated. Fall color varies from shrub to shrub. Color could be yellow, red, or purple. Has white flat-topped flower clusters. Has oval blue or blue-black fruit relished by birds. This viburnum grows well in sun to part shade and will sucker with the plant growing wider with time.
dilatatum - Linden viburnum grows to 10x8ft in an upright and open habit. Leaves are dark green, often lustrous, and a broad oval with coarsely-toothed leaf margins. The leaves are 4 ˝in long and are not sharply pointed. Fall leaves are russet red. Has creamy-white, flat-topped flower clusters. This viburnum will grow in sun to part shade. Fruit is 1/3in long, red or scarlet, and very showy.
farreri - Fragrant viburnum grows to 12x12ft in a loose, open habit. Its leaves are dark green, oval, with edges serrated and pointed. Leaves are 4in long. Flower buds are pinkish red. Has fragrant, white-tinged-with-pink flowers in a flat-topped flower cluster. It blooms before the leaves unfold which helps to make the flowers stand out. Fruit is red changing to black when it matures.
x juddii - Judd viburnum is said to be a superior carlesii with a full and rounded habit. Grows to 8x8ft. Leaves are dark green, oval to round, slightly serrated, pointed and 4in long. Its flowers are white, fragrant, and snowball-type. Its red fruit changes to black. (carlesii x bitchiuense)
nudum - Smooth Witherod viburnum is a native shrub found in eastern North America. It grows to 10x10ft in an upright form. Has lustrous, dark green, elliptic, pointed leaves. Its fall leaves are red to red purple. Has creamy-white flowers in a flat-topped flower cluster. Its fruit is red to purple.
opulus - European Cranberrybush grows to 15x15ft in a multi-stemmed, arching habit giving the overall impress of a rounded shrub. Plant in sun or part shade. Its leaves are glossy, dark green, deeply lobed, and grow to 4in long and wide. The fall foliage is variable being yellow-red or red-purple. Has white lacecap-type flowers with white, fertile, inner flowers and showy, outer, sterile flowers in flat-topped flower cluster. Its fruit is bright red.
plicatum - Japanese Snowball grows to 15x15ft in an upright form. Has dark green, broad oval, ridged leaves coming to a sharp point. White sterile flowers are formed into a rounded, snowball-type cluster.
plicatum var. tomentosum - Doublefile viburnum grows to 9x12ft in a horizontal form. Its leaves are dark green and broadly oval and have a sharp point. Its flowers are non-fragrant, pure white, lacecap-type flowers with white, fertile, inner flowers, and large, outer, sterile flowers in a flat-topped flower cluster. Has red-purple fall leaves and red fruit changing to black. Fruit is very showy and devoured by birds during the summer. As it grows large, one way to control its size is to cut it back to 12in high every few years.
The Doublefile viburnum is for me the star plant of the viburnums. It looks like a dogwood when in bloom. This species does require some effort to grow it well as it is a large-growing shrub, needing a wide space. It is stunning in the spring with its beautiful white flowers growing on wide, horizontally tiered stems. After flowering, the show goes on with its showy red fruit sitting on top of its wide stems just waiting to be eaten by birds. In the fall it again puts on a beautiful display when the leaves turn.
prunifolium - Blackhaw viburnum is a native shrub growing in eastern North America. Grows to about 15x12ft in an upright to rounded form. Its leaves are broadly oval and pointed, dark green in color, and grow to 3.5in long. Its flowers are creamy white and are in a flat-topped flower cluster. Fall leaves are purple to red. Its edible fruit is pink changing to blue black. Plant in sun or shade; it is adaptable in its soil requirements including dry soil.
x pragense - Prague viburnum grows to 10x10ft and its habit is upright to oval. It is said to be extremely fast growing and needs pruning to keep it dense. Its evergreen, lustrous, dark green, oval leaves are 4in long and are do not come to a sharp point. Flower buds are pink. Creamy-white, slightly fragrant flowers are in a flat-topped flower cluster. (This is a cross between rhytidophyllum and utile)
rhytidophyllum - Leatherleaf viburnum grows to 15x15ft in an upright, multi-stemmed habit. Its evergreen, long, narrow, dark green, leathery leaves are rough and grow to 7in long. Leaves are only slightly pointed. Its flowers are lightly fragrant, creamy-white in a flat-topped flower cluster. Its fruit starts red and changes to black. This viburnum tolerates heavy shade but needs protection from wind.
sargentii - Sargent viburnum grows to 15x15ft in a multi-stemmed, upright to rounded form. Its green, strongly-lobed, maple-like leaves are up to 5in long and have a smooth, leathery texture. Fall leaves are yellow to red. Has white lacecap-type flowers with white, fertile, inner flowers and large outer, sterile, flowers in a flat-topped flower cluster. Its fruit is translucent bright red. It's a vigorous grower and is more resistant to aphids than European Cranberrybush .
setigerum - Tea viburnum grows to 12x9ft in an upright, multi-stemmed form. As the plant matures it takes on a weeping habit which is very beautiful when properly placed in the landscape. It has narrow oval, pointed, lustrous, dark-green leaves to 6in long. Leaves turn a dark red purple in the fall. Has creamy-white flowers in a flat-topped flower cluster. The flowers are secondary to its showy bright, warm-red fruit which lasts into winter because the birds don't eat right away.
I have several plants of this species planted at the top of a hill with ground cover underneath them. Hilltop siting is best because the stems eventually arch over and since we are looking at the plant from below, we see a gorgeous spectacle in the fall and winter with the cascading plants laden with bright red berries. Give it plenty of room and never cut back its stems as you will be destroying this plant's beauty. As it ages, and as with most all deciduous plants, cut one-third of the oldest stems back to the ground each year before new growth starts. In this way, there will always be fresh, new growth with plenty of fruits for viewing and for the birds.
trilobum - American Cranberrybush is a native shrub naturally found in eastern North America. It grows to 12x12ft in a dense, rounded form. Its lustrous, medium-to-dark-green, lobed, maple-like leaves come to sharp points. Fall leaf color is yellow to red purple. Its leaves are lacecaps with white, inner, fertile flowers and white, outer showy, sterile flowers in a flat-topped flower cluster. Its fruit is bright red and very showy.
utile - Service viburnum grows to 6x6ft with an open habit. Leaves are small, oval, wavy, evergreen, and lustrous dark green. Flower buds are pink. Has slightly fragrant, white, flat-topped flower clusters. The fruit is bluish black. Many great cultivars have utile as one of its parents. Among the best is:
I hope I have peaked your interest in viburnums. There are so many of them, that I'm sure you'll find the perfect viburnum for that garden space of yours.
Also, all viburnum species have similar characteristics that show that they are related to each other. The first one is that they all have "simple" leaves with a leaf bud appearing at the point or "axil" where the each leaf is attached to the stem. Other examples of "simple" leaves are maple, beech, and oak. See example:
Another characteristic of all viburnums is that two leaves are "opposite" meaning that the leaves and their buds are directly across from each other on the stem. See example.
Another characteristic is the shape of the leaf which in viburnums tend to be "ovate" or "elliptical". And yet another characteristic is that the margins of the leaves tend to be "serrate", "incised", "undulate", or "lobed".
As to flower shape, all viburnums have a "cyme" type flower configuration which is a wide-spreading group of small and/or large flowers at the end of the flower stalk with the inner flowers opening first. Dogwoods and viburnums are examples. The cymes are either snowballs or semi-snowballs (similar to the summer-blooming PeeGee Hydrangeas), lacecaps (as in the flat-topped hydrangeas such as "Tokyo Delight" with tiny, fertile flowers in the center and larger, showy, sterile flowers on the outside), and flat-topped flower clusters made up of all tiny, fertile flowers.
To learn more about plant structure and morphology, try one of these websites: