History & Introduction

Lonicera fragrantissima, or winter honeysuckle, is a species of flowering plant in the honeysuckle family, Caprifoliaceae. This plant is native to China, and has been an introduced species in other parts of the world. It was brought to the attention of western gardeners by botanist Robert Fortune, who had been plant hunting in China for the Royal Horticultural Society of London. Fortune introduced winter honeysuckle to England in 1845, and several years later, it was introduced to the United States. This plant is considered a “harbinger of spring” due to its early flowering traits. This plant is hardy to Zone 4, meaning it has a wide growth range. It can be found growing in the eastern United States from Ohio to New York, and down to the southern states as well, where it is becoming known as a problematic invasive species. In New York State and LIISMA, winter honeysuckle is ranked as a Tier M on the NYS Tier Ranking List, meaning more research and monitoring of the species is needed to better understand its invasiveness in our region. However, this plant appears to be migrating quickly throughout the eastern United States and may soon be a candidate for reassessment in its tier ranking. 

Identification & Biology

Winter honeysuckle is a species of “bush honeysuckle”. It is a broadleaf, semi evergreen shrub known to grow anywhere from 3-10 ft. tall, and sometimes reaching heights of 15 ft. The stems are solid, with a white pith, and the bark is stringy and tan when mature, but oftentimes purplish in color when they are young. When mature, the plant is an irregularly mounded, tangled mess of branches sprouting from the base, with a cane-like growth habit. Leaves are known to be opposite, elliptical to broadly ovate and 1-3 in. long and wide, and usually persist into winter. The leaves have crenulate (finely scalloped) margins and midribs are covered in bristles. Flowering occurs in the winter, from December to March, when lemon scented, creamy white, thin petaled flowers develop in pairs at the leaf axils. The plant produces abundant berries in spring that ripen to orange or red in the mid summer, and often persist throughout winter. 

Damage & Concern

As is the case with other invasive honeysuckles, winter honeysuckle is known to spread rapidly in other regions, forming dense understory thickets that outcompete native vegetation, decrease light availability, and potentially release toxic allelochemicals into the soil, inhibiting plant growth in its vicinity. The plant is difficult to control, due to copious amounts of fruit being dispersed by birds and wildlife,  rigorous resprouting from the base, and like other invasive bush honeysuckles, is known to reproduce from root fragments. 

Management & Control 

Manual/Mechanical Control

Grubbing: This method is appropriate for small populations or environmentally sensitive areas where herbicides cannot be used. Using a pulaski or similar digging tool, remove the entire plant, including all roots. Juvenile plants can be hand pulled depending on soil conditions and root development. Larger stems, up to 2.5 in., can be removed using a weed wrench or similar uprooting tools. Any portions of the root system that are not removed may resprout. All plant parts, including mature fruit, should be bagged and disposed of to prevent reestablishment.

Chemical Control

Foliar Spray Method: This method should be considered for large thickets of winter honeysuckle where risk to non-target species is minimal. Air temperature should be above 65°F to ensure absorption of herbicides.

Glyphosate: Apply a 2% solution of glyphosate and water plus a 0.5% non-ionic surfactant to thoroughly wet all leaves. Use a low pressure and coarse spray pattern to reduce spray drift damage to non-target species. Glyphosate is a non-selective systemic herbicide that may kill non-target partially-sprayed plants.

Triclopyr: Apply a 2% solution of triclopyr and water plus a 0.5% non-ionic surfactant to thoroughly wet all leaves. Use a low pressure and coarse spray pattern to reduce spray drift damage to non-target species. Triclopyr is a selective herbicide for broadleaf species. In areas where desirable grasses are growing under or around winter honeysuckle, triclopyr can be used without non-target damage.

Cut Stump Method: This control method should be considered when treating individual bushes or where the presence of desirable species precludes foliar application. This treatment is effective as long as the ground is not frozen.

Glyphosate: Horizontally cut winter honeysuckle stems at or near ground level. Immediately apply a 25% solution of glyphosate and water to the cut stump, covering the outer 20% of the stump.

Triclopyr: Horizontally cut winter honeysuckle stems at or near ground level. Immediately apply a 25% solution of triclopyr and water to the cut stump, covering the outer 20% of the stump.

Basal Bark Method: This method is effective throughout the year as long as the ground is not frozen. Apply a mixture of 25% triclopyr and 75% horticultural oil to the basal parts of the shrub to a height of 12-15 in. from the ground. Thorough wetting is necessary for good control; spray until run-off is noticeable at the ground line.

When considering the use of pesticides, it is your responsibility to fully understand the laws, regulations and best practices required to apply pesticides in a responsible manner. At times, the pest you seek to treat may not be on a pesticide label, requiring a 2ee exemption from NYSDEC.  Always thoroughly read the label of any pesticide, wear the appropriate safety equipment needed, and consult the NYSDEC or a licensed pesticide applicator with questions. 

Monitoring & Reporting

LIISMA is currently monitoring winter honeysuckle as part of our Early Detection and Rapid Response program. As reports of the species are collected, LIISMA is dedicated to delineating and managing any early emerging infestations of the species before they become widespread. Winter honeysuckle is currently a Tier M species on Long Island, meaning it is a species that requires more research, mapping, and monitoring to understand its invasiveness and impacts.

Your reports matter to us– report the species to iMapinvasives or iNaturalist as soon as you detect it!

iNaturalist is an app and website that can help you record your own observations, identify species, collaborate with others, and access the observational data collected by iNaturalist users. 

Already using iNaturalist? Join a LIISMA iNaturalist Project to have your invasive species observations automatically uploaded to our projects! Here are some of our projects you can join: Invasive Species in Priority Areas, EDRR Species, LIFERS, Tier 1 Invasive Species, and more!

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