Amur honeysuckle (Lonicera maackii)

Synonyms: Lonicera maackii var. podocarpa, Caprifolium maackii, Xylosteon maackii

Common Names: Bush honeysuckle, late honeysuckle

Description:

Amur honeysuckle (Lonicera maackii) is a large, invasive shrub from northeastern Asia that was brought to the United States around 1898 as an ornamental and for wildlife cover [1]. It has long since escaped from plantings and now forms dense thickets in woods, edges, and yards across the eastern and midwestern United States [1]. MISIN tracks it because it leafs out early, shades out native wildflowers and tree seedlings, and spreads fast as birds carry its red berries far and wide [2][3].

Habit:

Amur honeysuckle is a multi-stemmed deciduous shrub that can grow 15 to 20 feet tall, often forming dense thickets [1][2]. Its leaves are arranged in pairs (opposite) and are oval with a long, tapered point at the tip [1]. In late spring it bears paired, tubular flowers that open white and fade to yellow, followed by pairs of round red berries that ripen in late summer and fall and often hang on into winter [1][2]. A reliable check on older stems: cut one and look at the center ? Amur honeysuckle has a hollow, brown or tan pith, while native shrub honeysuckles have a solid white center.

The easiest time to find it is late fall and early spring. It leafs out earlier than native plants in spring and holds its green leaves later into fall, so it stands out as a green shrub when the woods around it are bare [2]. The bright red berries also make it easy to spot in autumn [1].

At-a-glance cues:

1. Large multi-stemmed shrub, up to 15?20 feet tall, often in dense thickets [1][2]
2. Paired, oval leaves with a long, tapered point; green earlier and later in the year than nearby native plants [1][2]
3. Older stems have a hollow brown or tan center (native honeysuckles are solid white inside)
4. Paired round red berries in late summer through winter [1]

Leaves:

1. Arranged in pairs (opposite) along the stem [1]
2. Oval to egg-shaped with a long, gradually tapered point at the tip, up to about 3? inches long [1]
3. Margins smooth (untoothed) [1]
4. Surface slightly hairy, especially along the veins beneath [1]

Stems:

1. Woody, multi-stemmed, upright, forming a large shrub 15?20 feet tall [1][2]
2. Older stems have a hollow brown or tan center (pith) ? native shrub honeysuckles have a solid white center
3. Bark is grayish-brown and becomes ridged or shaggy with age [2]
4. Roots are shallow, so smaller plants pull out fairly easily [2]

Flowers:

1. Tubular, two-lipped flowers about an inch long, in pairs where the leaves meet the stem [1]
2. Open white and fade to pale yellow or cream; fragrant [1]
3. Bloom in late spring, about late May into June [2]
4. Each flower has both male and female parts [1]

Fruit and seeds:

1. Fruit is a round, juicy red berry, borne in pairs in the leaf axils [1]
2. Berries ripen in late summer and fall and often stay on the plant into winter [1]
3. Each berry holds several small seeds [1]
4. Birds eat the berries and spread the seeds widely [2]

Habitat:

Amur honeysuckle grows in a wide range of conditions, which is part of why it spreads so well. It is common in forests and forest understories, along woodland edges, in old fields, fencerows, floodplains, roadsides, and yards [2]. It grows in full sun and in shade and tolerates many soil types [2].

The plant is native to northeastern Asia ? China, Korea, the Russian Far East, and Japan [1]. It was introduced to the United States around 1898 as an ornamental and for wildlife cover and erosion control, then escaped cultivation, and is now widespread across the eastern and midwestern United States [1].

Reproduction:

Amur honeysuckle spreads by seed, and birds are the main carriers. They eat the red berries and drop the seeds far from the parent plant, including into yards, fencerows, and the middle of woods [2]. It also spreads from shrubs that people planted years ago. So it can arrive as a bird-dropped seedling under a tree or a fence, or spread from an old ornamental shrub nearby.

The shrub produces large numbers of berries, each with several seeds, and seedlings establish readily on bare or shaded ground [1][2]. It does not creep by underground stems, but cut stumps resprout vigorously, so simply cutting a plant is not enough [2]. The best control timing is late fall or early spring, when the shrub is easy to see and seedlings can be pulled before berries form [2].

Impact and Damage:

Amur honeysuckle is not poisonous to people, and its berries are not a human food. The real damage is to gardens and natural areas. It leafs out early and grows into dense thickets that cast heavy shade, crowding out native wildflowers, shrubs, and the tree seedlings a forest needs to renew itself [2]. In a controlled study, native tree seedlings grew more slowly and survived less often when growing with Amur honeysuckle than without it [3].

For natural area stewards, the result is forests where little grows beneath the honeysuckle, lower plant diversity, and poor tree regeneration [2][3]. Birds spread the berries widely, which helps the shrub invade new ground quickly [2]. Because it tolerates sun and shade and many soil types, a few plants can grow into a solid understory layer over time [2].

Similar species:

Several other bush honeysuckles look much like Amur honeysuckle, and all the invasive ones share a hollow stem center, while native shrubs have a solid white center.

Morrow's honeysuckle (Lonicera morrowii) is a similar invasive shrub, but its leaves are more rounded and densely gray-hairy underneath, lacking Amur's long tapered leaf tips [2][4].

Tatarian honeysuckle (Lonicera tatarica) has smooth, blue-green, hairless leaves and pink to white flowers, while Amur's leaves are hairy and long-pointed [2][4].

Bell's honeysuckle (Lonicera ? bella) is a cross between Morrow's and Tatarian and looks in between them; like the others it is invasive and hollow-stemmed [2][4].

Native bush honeysuckle (Diervilla lonicera) is a smaller native shrub with toothed leaves and yellow flowers, and its stems are solid inside, not hollow.

Monitoring and rapid response:

Signs to watch for:

1. Large, multi-stemmed shrubs that are green earlier in spring and later in fall than the plants around them [2]
2. Paired red berries from late summer into winter, and paired white-to-yellow tubular flowers in late spring [1]
3. Hollow brown or tan centers in cut older stems

What you can do:

1. Pull or dig out seedlings and small plants, especially when the soil is moist ? the shallow roots come up fairly easily [2].
2. For larger shrubs, dig or grub out the whole root mass so the plant cannot resprout [2].
3. If you cut a large shrub, expect it to resprout from the stump, so plan to dig the roots or repeat the work [2].
4. Do this in late fall or early spring, when honeysuckle stands out among the bare native plants and you can remove it before berries form [2].
5. Bag and dispose of any branches that carry berries so the seeds do not spread.
6. Natural area crews should remove scattered outlier shrubs and seedling flushes first, then work across a site over repeat visits, paying special attention to edges and fencerows where birds drop seeds [2].

When to call a professional:

1. Large, mature thickets, or stumps that keep resprouting after cutting.
2. Sites where digging and pulling are not keeping the shrub in check.
3. For chemical control options, contact a licensed applicator or your local cooperative extension office.

Report sightings to MISIN. Help track this species' spread by submitting observations through the MISIN web site or the MISIN mobile app (Android, iOS, Windows, and macOS). Photos at multiple angles paired with a precise GPS location are the most valuable data for confirming new occurrences and triggering rapid-response review.

Credits:

1. USDA NRCS Plants Database. Lonicera maackii (Rupr.) Herder. plants.usda.gov
2. University of Illinois Extension. Invasive Amur Bush Honeysuckle. extension.illinois.edu
3. Gorchov DL, Trisel DE (2003). "Competitive effects of the invasive shrub, Lonicera maackii (Rupr.) Herder (Caprifoliaceae), on the growth and survival of native tree seedlings." Plant Ecology 166(1):13?24. semanticscholar.org
4. Wisconsin Department of Natural Resources. Amur Honeysuckle (Lonicera maackii). dnr.wisconsin.gov

---