Do you remember pulling honeysuckle flowers as a kid? The ones you could pull the stamen out of the back of the bloom to get a little drop of sweet nectar? Those honeysuckle flowers most likely came from the native vine or the less-invasive Japanese honeysuckle and are not the same as Asian bush honeysuckles, which originated from eastern China.

Invasive honeysuckles represent the species Lonicera maackii, L. morrowii, or the hybrid L. X bella, and are collectively known as bush honeysuckles. Much larger in size than the native vines, bush honeysuckles can grow 15-20 feet tall and form dense thickets, especially in urban areas.

They were introduced in the mid to late 1800s for landscape ornamentals, wildlife cover and erosion control. Bush honeysuckles are currently found statewide.

What are the characteristics of bush honeysuckle?

Bush honeysuckle is the first to leaf out in the spring and the last to drop leaves in the fall, which gives it a competitive advantage by shading out other plants.

Research suggests that bush honeysuckles exhibit allelopathic tendencies by producing a chemical that inhibits other plants from growing in its vicinity (although other invasives like winter creeper and bamboo seem to grow just fine amidst honeysuckle).

Other characteristics include:

• Opposite, simple leaves, 1-3” long and with pointed ends;
• Showy and fragrant white flowers in early summer that turn yellow as they age;
• Bright red or orange berries in the fall in clumps of two or four at the base of the leaves;
• Thornless bark with hollow stems in mature plants.

Why should we be concerned?

Bush honeysuckles take over riparian corridors and floodplains along streams, especially in urban areas. Riparian corridors and open woodlands provide the light needed in order to thrive. They out-compete and dominate forest understories that used to be the home of native plants, creating honeysuckle deserts from what were native woodlands.

While attractive to birds, bush honeysuckle berries are high in carbohydrates but low in fats and nutrients that migrating birds need to complete their journeys. Hence these berries are considered “junk food” for wildlife.  Bush honeysuckles reproduce and spread quickly because the berries have numerous seeds and have help dispersing from the birds that eat them. For example, the first bush honeysuckle outside of cultivation in the St. Louis area was discovered in 1983. In just three short decades it has come to dominate the St. Louis landscape to the tune of millions of plants.

How can it be controlled?

Bush honeysuckles are aggressive and often it takes a two-year commitment to fully eradicate them from an area; one year to take out the bulk and the second year to remove any re-sprouts or new seedlings.

Several different methods are used to remove honeysuckle:

Cut-stump method

Cutting the trunk low to the ground with a hand tool or chainsaw and applying a 20 percent glyphosate herbicide at the base is one of the most effective treatments for bush honeysuckle removal when done properly. However, careful application of the herbicide is necessary to prevent unwanted effects to surrounding environment, and re-sprouting may occur if herbicide is not accurately applied.

Hand-pulling

Small seedlings can easily be pulled in early spring when the ground is moist.

Digging

Because the roots are quite shallow, simply digging up the roots can be effective even for larger plants. However, this method is not recommended for widespread removal of large thickets due to the scale of land disturbance it may cause.

Fire

When burning can be conducted safely and with enough fuel, fire can assist in removing honeysuckle from the landscape, but prescribed burning may need to be repeated every spring or every two years for several years to be fully effective.

Foliar spray

This method uses a 2 percent glyphosate spray over the entire plant, but is only recommended in early spring or late fall when native plants have dropped their leaves or have not yet sprouted. Wind direction and  speed should always be considered to prevent herbicide from reaching non-target vegetation.

Considerations for the future

The unhinged invasive capabilities of bush honeysuckles will require a strong voluntary effort in order to reduce its spread. Education is a key factor in preventing the sale and cultivation of these invasive taxa. Proper identification is also extremely important, as many native plants can easily be mistaken for bush honeysuckle.

Consider native plants for landscaping in place of honeysuckle. Plants such as American beautyberry, black viburnum, flowering dogwood, deciduous holly, or Eastern Wahoo make excellent alternatives. All of these plants and other natives have stronger, deeper roots for preventing erosion and provide beneficial habitat and food sources for wildlife.