Most buckthorn varieties are easy-to-grow shrubs that make great privacy screens, backdrops, or hedges, thanks to their dense habit and lustrous, dark-green foliage. This deciduous shrub is an excellent hedge plant and can easily be maintained at a specific size with an annual pruning or called on to screen the view into a neighboring yard.
All parts of buckthorn shrubs are mildly toxic to humans and animals.
Buckthorn Overview
Where to Plant Buckthorn
Buckthorn shrubs are adaptable and can be grown in full sun or light shade. Although it grows best in moist, well-draining soil, buckthorn shrubs are able to grow in a variety of soil conditions. Buckthorn is primarily used as a hedge plant, but it can also be used as a leafy living wall to enclose a patio. A row of buckthorn planted along a lackluster garage wall transforms the sterile area into a backyard habitat.
Common or European buckthorn and glossy or alder buckthorn are invasive species. Rogue buckthorns degrade woodlands and wildlife habitats. In many areas, planting them is prohibited. Check with your local agricultural extension before planting.
A line of noninvasive buckthorns—'Fine Line' buckthorns—has recently been introduced.
How and When to Plant Buckthorn
Plant a nursery-grown buckthorn in spring, and water it regularly during the first growing season. After the shrub establishes a strong root system, it will better tolerate dry conditions. Dig a hole twice as wide and the same depth as the container. If the soil is poor, dig the hole slightly wider and deeper and amend it with compost. Remove the plant from the container and gently separate the roots. Set the plant in the hole at the same depth it was in the container and backfill with soil, pressing down to remove air pockets. Water thoroughly and add a 2-inch layer of mulch around the shrub.
When planting a bare-root shrub, soak the roots in water for a couple of hours before planting. Look for a darkened area on the plant that indicates the former soil line and plant it at the same depth as before. Prepare a hole as you would for a nursery plant. Then, form a mound of soil at the bottom of the hole to support the bare-root plant at the correct height. Backfill with one hand while holding the plant upright with the other. Firm the soil, water thoroughly, and mulch.
Buckthorn Care Tips
Light
Buckthorn is an adaptable shrub, but it grows best in full sun or partial shade.
Soil and Water
Buckthorn prefers moist, well-drained soil, but it tolerates a variety of soil types and environments, including dry foundation planting areas and planting spots that receive just a few hours of sunlight a day.
Temperature and Humidity
Hardy in USDA zones 2-9, buckthorn shrubs are rarely seen in areas where temperatures fall below 0°F, although some varieties can survive temperatures as low as -40°F. The shrub thrives in year-round humid conditions but adapts well to any environment other than arid conditions.
Fertilizer
Buckthorn shrubs need little encouragement to grow. A single application of a slow-release, granular fertilizer added to the soil in spring is sufficient.
Pruning
Prune buckthorn as needed in spring based on the type. Fine Line buckthorn displays an upright, columnar habit and rarely requires pruning. Narrow-leaf buckthorn exhibits an open habit and benefits from annual pruning to maintain a dense branching structure.
Pests and Problems
Watch for a variety of problems that include cankers, caterpillars, Japanese beetles, leaf spots, rust, and scale. In some instances, the roots may be attacked by nematodes.
How to Propagate Buckthorn
Buckthorn shrubs can be propagated by cuttings or seeds.
Cuttings: Take 6- to 8-inch softwood cuttings of new growth in late spring or summer. Make the cut beneath a leaf node and remove all the foliage from the bottom half of the cutting. Dip the end of the cutting in hormone powder and insert it into a 4-inch peat pot filled with moist soilless mix. Cover the cutting and pot with a plastic bag and place in a cool but bright location. When new growth appears, remove the plastic bag.
Seeds: Before sowing the seeds, soak them in hot water and leave them in the water for 24 hours. If it is autumn, sow them outside 3/8-inch deep in a prepared bed for spring germination. If it is any other time of year, place the soaked seeds in peat moss in a plastic bag and refrigerate them for 1-2 months. Remove the seeds from the refrigerator and sow them in 4-inch pots filled with seed-starting mix—one seed per pot. Cover them with a 3/8-inch layer of seed-starting mix and tamp it down. Water thoroughly and place in a cool but brightly lit area. The seeds should germinate in about five weeks. As soon as they develop a few sets of leaves, they are ready to be transplanted into the garden.
Types of Buckthorn
Fine-Line® Fern Leaf Buckthorn
Noninvasive Rhamnus frangula 'Ron Williams' grows 5 to 7 feet tall and 2 feet wide. It is part of the Fine Line® collection of noninvasive buckthorns. It adds texture and shape to the garden with its narrow columnar habit and lacy foliage. Zones 3-7.
Variegated Italian Buckthorn
Rhamnus alternus is an evergreen shrub that bears attractive gray-green foliage edged in white. It makes a great hedge thanks to its dense habit. It's also good as a specimen plant or patio tree. This variety grows 15 feet tall and 12 feet wide. Zones 7-9.
Buckthorn Companion Plants
Buckthorn produces berries in summer, making it a stopping place for birds. Pair buckthorn with other berry-producing shrubs to create a bountiful backyard buffet. Try easy-to-grow bird-friendly shrubs as companion plants, such as dwarf cranberry bush viburnum, beautybush (a member of the honeysuckle family), and Oregon grape holly.
Frequently Asked Questions
- Are there any noninvasive buckthorn shrubs?Most buckthorn shrubs in the U.S. are invasive in at least parts of the country. Only one recent addition—the patented 'Fine Line' buckthorn—is noninvasive. 'Fine Line' plants produce very few seeds and were the result of an unintentional cross of two buckthorn cultivars. It does not reseed or spread.
Most buckthorn shrubs in the U.S. are invasive in at least parts of the country. Only one recent addition—the patented 'Fine Line' buckthorn—is noninvasive. 'Fine Line' plants produce very few seeds and were the result of an unintentional cross of two buckthorn cultivars. It does not reseed or spread.
- Do deer eat blackthorn shrubs?In most areas of the country, blackthorn shrubs are deer-resistant. Mice, squirrels, and birds sometimes nibble on the berries, but blackthorn berries aren't very nutritious, so wildlife doesn't rely on them as a food source.
In most areas of the country, blackthorn shrubs are deer-resistant. Mice, squirrels, and birds sometimes nibble on the berries, but blackthorn berries aren't very nutritious, so wildlife doesn't rely on them as a food source.