Coral Honeysuckle (Lonicera sempervirens)

Trumpet honeysuckle (Lonicera sempervirens) is an eastern United States vine. It attracts hummingbirds, butterflies, and bees. Trumpet honeysuckle is grown for ornamental purposes, often as an alternative to the invasive species Japanese honeysuckle.

I. Appearance and Characteristics 

Lonicera sempervirens (commonly known as coral honeysuckle, trumpet honeysuckle, or scarlet honeysuckle) is a flowering plant species of honeysuckle vine native to the eastern United States which is known for its reddish flowers.

Lonicera sempervirens was first described by Swedish botanist Carl Linnaeus in his treatise Species Plantarum in 1753.

Lonicera sempervirens is best recognized by trumpet-shaped and coral to reddish flowers. The leaves and stems are waxy, a common trait in the honeysuckle genus. It is a twining vine growing to 20 ft or more through shrubs and young trees. The leaves are produced in opposite pairs, oval, up to 5 cm long and 4 cm broad; the leaves immediately below the flowers are perfoliate, joined at the base in a complete ring round the shoot. When born, their flowers are whorled on the end. They are present with red berries on them that are less than 1 cm width and length. The berries are inedible and grow from summer to fall. Their leaves are somewhat evergreen. The species is also flammable, which leads to it not being recommended for being planted close to residences. The flowers are produced on new growth in clusters of several groups of three together, tubular, 5 cm long, with five small lobes opening at the tip to expose the stamens and stigma. The bark is green and fuzzy when younger but becomes a light brown as it ages. The older stems get more of a red-orange color.

II. How to Grow and Care

Sunlight

Trumpet honeysuckle likes sufficient sunlight, so plant them where they can receive long lengths of light exposure time. This way they will thrive, growing denser branches and leaves and blooming in brighter colors. If they are planted in shady areas, the branches and leaves of trumpet honeysuckle will be more sparse and have fewer flowers and fruits. However, note that when the temperature is high and the sunlight is strong in the summer, these plants need shades to prevent too much sun exposure.

Temperature and Humidity

These plants are both heat tolerant and cold tolerant. Coral honeysuckle can withstand hard frosts and cold temperatures down to USDA zone 4. It prefers medium humidity levels, as high humidity can encourage powdery mildew.

Watering

Regularly check the moisture of the soil to determine whether a plant needs watering. If the soil is relatively dry, then water it to maintain a slightly moist soil condition. Trumpet honeysuckle in gardens with ample rainfall does not need watering. Make sure water does not accumulate in the soil. In drier weather, water the plants appropriately.

During summer, increase the amount of water provided. In winter, reduce it. Wait until the soil turns a lighter color before watering. It is recommended to water trumpet honeysuckle once every 3-5 days after pruning leaves or cutting off flowers. This will help it develop new branches and bloom more impressively. It is best to water it in the morning or early evening. Rainwater or snow water is better for watering than tap water. Tap water contains fluoride or chloride, which can cause soil compaction and worsen soil permeability, affecting the breathing of the roots.

Soil

Coral honeysuckle needs well-draining soil. As long as this need is met, this plant can adapt to a variety of soil conditions. If the soil does not drain well enough, adding compost can resolve the issue. Coral honeysuckle prefers acidic to neutral soil pH.  

Fertilizing

When planting trumpet honeysuckle in gardens, applying sufficient base fertilizer usually ensures normal growth. If they are planted in flower pots, apply water-soluble organic fertilizer in low concentrations once every 15-20 days in spring and summer. This will allow them to grow more healthily and produce better blooms. When buds appear, mix the organic fertilizer solution with an appropriate amount of fertilizer rich in phosphorus and potassium once or twice. This can promote more blooms and more beautiful flowers.

Planting Instructions

Transplanting trumpet honeysuckle is best done before spring when plants are germinating. If planted in the garden, 2-3 of them can be planted together. Add some organic or phosphate fertilizer as a base fertilizer. The plants need sufficient water after transplanting. Set up plant stakes and tie strings to them and the plant to help it climb up and form a green area.

If planted in a flower pot, trumpet honeysuckle needs to be placed on a balcony or similar space with sufficient sunlight. You can grow 1-2 plants in one big pot. Use a mixture of garden soil, leaf mold, and sand as potting soil. Before planting, fill the bottom of the flower pot with fully decomposed organic fertilizer, using phosphate fertilizer as the base fertilizer. After planting, water the plants sufficiently.

Pruning

Pruning should usually be done in fall after the leaves of trumpet honeysuckle drop, before germination. Fertilizing and pruning after blooming can encourage trumpet honeysuckle to bloom again. Stronger branches need light pruning while weaker branches need hard pruning. Dry or old branches need to be completely pruned because pruning older branches can help younger branches develop. 

Pruning the branches in the middle can promote air circulation in the center of the plant while also letting lower branches receive more sunlight.

After pruning, the plant’s branches will bloom at similar times, so you can harvest more flowering branches at a time. It is recommended to just lightly prune newly planted trumpet honeysuckle as long as its shape is controlled.

Propagation

By cuttings 

Propagation is easily done with softwood cuttings in late spring or summer. Take note of these instructions:

• Using sharp garden snips, trim a softwood vine that is around 6 inches long. 
• Remove the bottom sets of leaves. It is best to have around 2 exposed nodes near the cut end and two sets of leaves at the tip of the cutting. 
• At this point, either dip the cut end into rooting hormone and place the cutting in moist soil or place the cutting in water. 
• Place the cutting in indirect sunlight. If kept in water, be sure to change the water regularly. When roots appear, plant in well-drained potting soil, and continue to grow until large enough for planting in the garden.

As new growth appears and root growth is apparent (tug gently to check for resistance), transfer to your desired planting location.

From Seed

Propagation by seed is another way to grow coral honeysuckle. Here is how to gather and plant seeds:

• Remove the berry flesh and place the seeds in the refrigerator for around 3 months for cold stratification. 
• After this, plant the seeds and cover lightly with well-draining, moist soil.
• Place a plastic bag or tray over the seeds to retain moisture. 
• Keep the soil moist and remove the cover once seedlings appear.

Pests and Diseases

This hardy plant is generally unbothered by pests or diseases. You may occasionally see some aphids or powdery mildew, but these encounters are rare and generally resolve without major damage to your plant.

Aphids

Aphids are small insects that feed on plant juices. They will sometimes show up on fresh spring growth. If you see aphids gathering in clusters on your plant, spray them with some insecticidal soap or squirt them with a few jets of water to dislodge them from their feeding places. This is usually enough to discourage them from becoming a bigger issue.

Powdery Mildew

If you notice a grayish-white powdery coating forming on the leaves, it is probably a case of powdery mildew. This fungal infection loves moist, humid areas with poor air circulation.

It is not usually a problem for these plants, and a minor infection won’t cause any lasting damage. Prune off any obvious powdery mildew to prevent further spread to other portions of your vine or to other plants.

Mulch

Because these vines like consistently moist soil, mulch around your plant to help retain soil moisture. Use an organic, biodegradable mulch, such as shredded leaf mulch, wheat straw, or bark mulch. Refresh the mulch every year or two when it has decayed. 

Potting and Repotting 

To grow coral honeysuckle in containers, be sure to choose a container with good drainage holes. Fill it with a well-draining soil mix and keep it in a sunny location. When the honeysuckle fills the pot and no longer has room to grow, gently tip the pot onto its side to work the plant and its root system free. Place the plant in a slightly larger pot and fill it with fresh soil. 

Overwintering 

Because coral honeysuckle plants are cold tolerant and can withstand hard frost, there is not much required to overwinter these plants. Planting them near structures such as fences or trellises will help shelter them from cold winds. Additionally, adding mulch in the fall will help to insulate the root system from excessively cold temperatures.  If growing in a container that is not winterproof, bring the plant inside to grow as a houseplant during the winter.

III. Uses and Benefits 

• Ornamental uses

Lonicera sempervirens is often used as an alternative to the invasive Lonicera japonica across the east coast of North America. It is popular to grow in gardens or recreational areas as it is considered low maintenance. It is also used to attract hummingbirds and butterflies for pollinator gardens. The species is mainly used ornamentally on fences or lattices, and for the attractive red color of its flowers.

• Medicinal uses

It has been used to treat asthma and bee stings in Native American traditions.

• Wildlife uses

Lonicera sempervirens is used by many animals for food, most commonly used for nectar by butterflies and hummingbirds. It attracts bees, hummingbirds, moths, and even songbirds. Birds such as quail, purple finch, and American robins eat the red berries. Ruby-throated hummingbirds and insects pollinate the bright red to pinkish-red flowers from mid-spring to fall. It hosts the caterpillars of spring azure and snowberry-clearing moths. Lonicera sempervirens is used moderately for animal cover and has a relatively low nutritional value.