Glossy Buckthorn (Frangula alnus)

How much light does a Glossy Buckthorn need?

Glossy buckthorn does best in full sun, which means six or more hours of direct sunlight a day. It can also grow in part shade, and Penn State Extension says it can grow in full or partial sun. Full sun remains the preferred condition among those listed.

• Light: Full sun and part shade (full sun preferred)^1,2

How often to water a Glossy Buckthorn

Water needs for this shrub run from medium to wet. It does well in most consistently moist soils that are not waterlogged. Moderately fertile soil is part of the same description. Drainage is listed as good, and the site can be occasionally wet.

• Water: Medium to wet¹

Best soil for a Glossy Buckthorn

Soil drainage for glossy buckthorn is listed as well drained and occasionally wet. Good drainage is one listed condition. Occasionally wet is the other. The plant does well in most soils that are consistently moist but not waterlogged. Those soils are described as moderately fertile. Medium to wet is the documented water range for this plant. No cited source records a soil pH range for glossy buckthorn, so that value is not documented here.

• Soil drainage: Well drained and occasionally wet^1,1

Hardiness and temperature

Glossy buckthorn is rated for USDA hardiness zones 2a through 7b. The cold end of that range is zone 2a, and the warm end is zone 7b. The listing names every half-zone between them: 2a, 2b, 3a, 3b, 4a, 4b, 5a, 5b, 6a, 6b, 7a and 7b. Zones 2a–7b is the full documented range for this shrub or small tree.

• Hardiness: Zones 2a–7b¹

How to plant a Glossy Buckthorn

Check that your site falls within USDA zones 2a to 7b before planting glossy buckthorn. Plan for a mature spread of 8–12 ft (2.44–3.66 m). The height reaches up to 25 ft (7.62 m). Full sun is the preferred light for this shrub. Its growth rate is slow. In the contiguous United States its status is listed as introduced.

• Hardiness: Zones 2a–7b¹

Winter care

The listed hardiness for glossy buckthorn runs from zone 2a to zone 7b. Zone 2a is the coldest zone in that range. Zone 7b is the warmest zone in that range. Zones 3a through 7a lie between those two ends. Gardeners in zones colder than 2a or warmer than 7b fall outside the documented range.

• Hardiness: Zones 2a–7b¹

How to propagate a Glossy Buckthorn

Glossy buckthorn can be propagated by seed, stem cuttings and layering. Layering is named directly in the Plant Toolbox listing. Those are the three methods documented for this plant. Seed is the first method on that list. Stem cuttings are the second option, and layering is the third.

• Propagation: Seed, stem cuttings and layering¹

Common problems

Japanese beetles, caterpillars and scale are listed as pests that can affect this plant. Nematodes can attack the roots. Margarodes vitis is also recorded among its pests. Cankers, leaf spots and rust can be problems. Silver leaf fungus, cherry leaf roll virus and Xylella fastidiosa are also recorded as diseases.

• Common pests: japanese beetles, caterpillars, scale, nematodes and margarodes vitis^1,1,3
• Common diseases: canker, leaf spot, rust, silver leaf fungus, cherry leaf roll virus and xylella fastidiosa^1,3,3,3

Questions and answers

How much sun does glossy buckthorn need?

Full sun is preferred, which means six or more hours of direct sunlight a day. It can also grow in part shade. Penn State Extension says it can grow in full or partial sun.

How big does glossy buckthorn get?

It is a tall understory shrub or small tree up to 25 ft (7.62 m) high. The mature spread is 8–12 ft (2.44–3.66 m). Its growth rate is slow.

What do the flowers of glossy buckthorn look like?

Each flower is about ¼ inch across, with five white petals. The sepals are yellowish green to white. The flowers appear in May or June, clustered in the leaf axils.