University of Vermont Extension 
Department of Plant and Soil Science

Anytime News Article

ALTERNATIVES TO BUCKTHORNS
 
Dr. Leonard Perry, Extension Professor
University of Vermont
 
 
You should avoid planting buckthorn in landscapes as birds spread their seeds to natural areas where they become invasive.  For this reason, some states now prohibit their sale.  There are many good alternatives to plant instead of buckthorn, or to replace existing ones in landscapes.  These include American hornbeam, witchhazel, black chokeberry, highbush blueberry, spicebush, serviceberry, and viburnums.

The two primary introduced species of buckthorn to avoid are the common (Rhamnus cathartica) and the glossy or European (Frangula alnus, formerly Rhamnus frangula).  These form large shrubs or small trees to 20 feet high or more, with a spreading and irregular habit.  Twigs of the common buckthorn often have spines on the tips.  The leaves remain dark glossy green late into the fall. Yellowish-green flowers in spring on female plants near bases of leaf stalks are followed in fall by small black fruits. 

Most of the fruits fall below the shrubs, forming a dense thicket that crowds out other plants.  Birds and mice eat the fruit, which produces a laxative effect furthering their distribution.  Originally introduced into our country as an ornamental shrub, for wildlife habitat, and for fence rows, these species now are spreading to open fields as well as edges of forests and clearings.

Before removing any buckthorns from natural areas, make sure it is one of these species.  There are several native American buckthorns that pose no problem.  The Carolina buckthorn (R. caroliniana) has finely toothed leaves like the black cherry, and the alder buckthorn (R. alnifolia) is a low-growing shrub to only three feet high.

The American hornbeam (Carpinus caroliniana) also is called musclewood as the bark is sinewy as leg muscles.  Reaching about 20 to 30 feet high, and about half that across, this hardy (USDA zone 3) native plant grows well in sun or shade in moist soils.  It makes a dense, rounded tree with hanging clusters of fruit in summer, and brilliant red leaves in fall in sun (yellow in shade).  Place it well to begin with, as it doesn’t transplant easily.

There are several nice witchhazels to choose from, the hybrids often reliably hardy to warmer areas (USDA zone 6).  The common witchhazel (Hamamelis virginiana) is a native, upright shrub reaching 12 to 15 feet high, and half that wide.  It is hardy (USDA zone 4), and although grows more dense in sun also tolerates shade.  It is attractive for its yellow flowers in fall as the yellow leaves are falling.

If you want a small shrub, consider the native black chokeberry (Aronia melanocarpa).  Only reaching 4 to 5 feet high, it can spread more.  It is hardy (USDA zone 3), grows in sun or part shade, and tolerates wet or dry sites.  The white flower clusters in mid-spring are followed by purplish-black fruit.  Being tart they are not favored by birds, but make nice jams.  ‘Autumn Magic’ is a compact selection with slightly larger fruits and good red fall color.

Highbush blueberry (Vaccinium corymbosum) is a good native alternative to the burning bush, not quite as tall but also with red fall color on several selections.  Its many burgundy, young twiggy stems give it winter interest too. This plant of course has edible berries for people and wildlife.  Even though it is self-pollinating, you may get more fruit from using at least two selections.  It can tolerate occasionally wet soils.

There are many cultivars (cultivated variety) available of the highbush blueberry, varying some in hardiness and fall leaf color.  Common hardy ones with orange-tinted fall color are ‘Bluejay’ and the lower ‘Patriot’.  Good choices for red fall color are the hardy Friendship’, getting only 2 to 3 feet high and wide; ‘Tophat’, getting only 1 to 2 feet high and 2 to 3 feet wide (hardy to USDA zone 5); and the hardy ‘Toro’ (USDA zone 4), getting 4 to 6 feet high and wide.     

Spicebush (Lindera benzoin) forms a neat, spreading mound 6 to 10 feet high and slightly wider.  The stems smell spicy when crushed.  This native plant adapts to wet or dry soils, and to sun or shade.  Female plants have scarlet berry-like fruit.  Unfortunately, it may only be hardy to warmer areas (USDA zone 5).

There are several native species of serviceberry that form large shrubs, or multi-stem small trees.  The Allegheny serviceberry (Amelanchier laevis) is perhaps the most commonly found in our area.  Reaching 15 to 25 feet high, and half that wide, it has an upright and open habit.  It grows well in sun or shade, and is quite hardy (USDA zone 3).  The attractive white spring flowers are followed by edible black fruits, then in fall by attractive red to orange leaves.

There are several native viburnums you could use as alternatives to buckthorns, but keep in mind species have varying susceptibility to a new pest, the Viburnum leaf beetle.  Witherod (V. cassinoides) is less susceptible, reaching 8 to 10 feet high and wide.  White flowers lead to fruit that start green, then change to red before black.  The orange-red fall leaves are attractive.  Witherod is quite hardy in wide-ranging light and soil conditions. 
   

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