Cephalanthus is an ornamental garden plant with glossy green leaves; fragrant white flowers; tan, brown, or red fruits; fall color; and an attractive structure, offering four-season appeal in the landscape. This native shrub provides food, shelter, and nesting habitat for a wide array of beneficial insects, birds, and other wildlife, making buttonbush one of the best plants for native gardens, pollinator borders, and other natural areas.
| Common name | Buttonbush, Button Bush |
| Botanical name | Cephalanthus occidentalis |
| Family | Rubiaceae |
| Species | occidentalis |
| Origin | East Canada, U.S.A to Central America, Cuba |
| Life cycle | Woody |
| Plant type | Native Plant |
| Hardiness zone | 5, 6, 7, 8, 9 |
| Sunlight | Full Sun |
| Soil condition | Clay |
| Soil ph | Acid |
| Drainage | Poorly Drained |
| Growth rate | Medium |
| Harvest time | Summer |
| Flowering period | Summer |
| Height | 5 ft. – 8 ft. |
| Width | 5 ft. – 8 ft. |
| Flower color | Cream, Tan |
| Leaf color | Green |
| Stem color | Brown, Copper |
| Fruit type | Capsule |
| Fruit benefit | Showy |
| Flower benefit | Fragrant |
| Garden style | Butterfly Garden |
| Uses | Meadow |
I. Appearance and Characteristics
Cephalanthus occidentalis is a species of flowering plant in the family Rubiaceae that is native to eastern and southern North America. Common names include buttonbush, common buttonbush, button-willow, buck brush, and honey-bells.
Cephalanthus occidentalis is a deciduous shrub or small tree that averages 1–3 m (3.3–9.8 ft) in height, but can reach 6 m (20 ft). The leaves are opposite or in whorls of three, elliptic to ovate, 7–18 cm (2.8–7.1 in) long and 4–10 cm (1.6–3.9 in) broad, with a smooth edge and a short petiole. The flowers are arranged in a dense spherical inflorescence 2–3.5 cm (0.79–1.38 in) in diameter on a short peduncle. Each flower has a fused white to pale yellow four-lobed corolla forming a long slender tube connecting to the sepals. The stigma protrudes slightly from the corolla. The fruit is a spherical cluster of achenes (nutlets).
There are two varieties, not considered distinct by all authorities:
- Cephalanthus occidentalis var. occidentalis (syn. var. pubescens) – common buttonbush. Eastern North America from Nova Scotia west to Minnesota and south to Florida and east Texas.
- Cephalanthus occidentalis var. californicus – California button-willow. Southwestern North America, from west Texas west to California (Sierra Nevada foothills, San Joaquin Valley, Sacramento Valley, and the Inner North Coast Ranges) and south to Mexico and Central America.
Buttonbush is a common shrub of many wetland habitats in its range, including swamps, floodplains, mangrove, pocosin, riparian zones, and moist forest understory. It is a member of the flora in the Everglades.
II. How to Grow and Care
Sunlight
Buttonbush prefers partial to full sunshine. It often grows better in full sun exposure but it can be a delicate balance. Shrubs planted where the sun readily dries out the soil will struggle to thrive.
Temperature and Humidity
The hardy nature of buttonbush shrubs contributes to their success in USDA hardiness zones 5 to 11. They are heat-resistant, cold-resistant, and extremely resilient when faced with overly wet conditions. This makes them great for a wide range of climates. They look their best in temperatures ranging from 61 to 75 degrees F. and are tolerant of high levels of humidity as long as there is plenty of water available. Dry, arid conditions are not suitable for growing buttonbush.
Watering
Common buttonbush usually grows on riverbanks and in other wet places in nature, and needs consistently moist soil. Water whenever the surface of its soil dries out, watering deeply and slowly while making sure that the soil drains.
Soil
Buttonbush is perfect for low-lying, wet areas where other plants may not grow well. It adapts to various soil conditions even though it is most often found in alluvial areas with sand and silt. Buttonbush prefers a neutral to slightly acidic soil with a soil pH level of 6.8 to 7.2 and does not perform as well in alkaline soil.
Fertilizing
Fertilize your mature common buttonbush with a balanced granular fertilizer or high quality compost once a year in early spring, applying it to the soil surface beneath the branches. Do not fertilize young plants at all during their first growing season.
Pruning
Because of its size, many people prefer to keep buttonbush pruned. When left to grow untrimmed, the shrub takes on an irregular shape. Wayward or scraggly branches can be trimmed away for a more manicured look. Alternatively, these shrubs can be limbed-up, which refers to removing lower branches to establish a more tree-like shape.
If it becomes unmanageable, simply cut the shrub down to the ground in early spring. Because it is such a fast grower, it will produce new growth very quickly.
Propagation
Buttonbush can easily be propagated through stem cuttings. It is best done in the spring when new growth appears. You will need a small pot, moist soil, rooting hormone, and a sharp knife. Then follow these instructions:
- Select a stem that is around 4 to 6 inches long. It should have a node and some leaves on it.
- Using a sharp, clean knife, cut the stem below a node.
- Remove any lower leaves, keeping only the upper leaves.
- Dip the cut end into rooting hormone and shake off any excess.
- Fill the small pot with moist soil and poke a hole into the soil with your finger.
- Slide the cutting into the hole and firmly press the soil around the cutting.
- Place the cutting in an area with bright, indirect lighting and keep the soil moist.
- Roots should develop in a couple of weeks. Once roots form and new growth appears, you can transplant the cutting to its permanent location.
How to Grow from Seed
Starting buttonbush from seed is simple. The seeds do not require stratification and can therefore be planted directly into the ground or in small starter pots. You will need moist soil and small pots. Then follow these instructions:
- Collect ripe seeds in the fall or use a purchased packet of seeds.
- Plant the seeds in moist soil, making sure to remove any weeds and trim back any plants that could compete with the buttonbush’s growth. Alternatively, you can start seeds in small pots.
- Keep small pots in a sheltered greenhouse or covered area, as these are more susceptible to cold.
- Seedlings should appear in the spring once temperatures are warm enough.
- Keep the soil moist. If the seeds were started in pots, continue to repot the seedlings into larger pots.
- Once the potted seedlings are at least a year old, transfer them to the garden, spaced about 3 feet apart.
Potting and Repotting
Buttonbush’s large size makes it a bit tricky to keep in pots. However, young, small shrubs or dwarf varieties can be kept in large pots. If you choose to keep a buttonbush in a pot, select container material that helps the soil stay moist, such as plastic or coated ceramic. Steer away from terra-cotta, as this material wicks away moisture and dries the soil. Despite its adaptation to extremely wet soils, the pot should have drainage holes. If you choose a standard potting mix, adding a handful or two of perlite or sand will help to mimic the plant’s native soil conditions.
Once the shrub fills the container, tip it on its side to gently slide the shrub out. Plant into a larger container or the ground in moist soil. Keep in mind that potted buttonbush plants will need constant watering since they do not have access to underground water sources.
Overwintering
Because these shrubs can handle temperatures that dip below 0 degrees Fahrenheit. they don’t need much extra care to survive cold winters. Potted shrubs should be moved to a protected area. For shrubs in the garden, simply apply mulch around the plant to help insulate the roots and retain moisture.
Pests and Diseases
Common Pests and Plant Diseases
Besides the occasional deer foraging on buttonbush, you can expect pests such as lygus bugs (insecticides will kill nymphs), a few leafhoppers, and thrips. These pests can cause misshapen, stunted, or yellowed leaves. Remove problematic leaves for minor infestations. Use other controls, such as insecticidal soap for heavier infestations.
This shrub does not attract diseases, though you may have a case of brown leaf spot. The spots look like little spores that may enlarge into blotches. This typical fungal infection does not require treatment other than removing infected leaves, cleaning up around the base of the shrub to prevent spread, and pruning to allow more sunlight and airflow into the plant.
Common Problems
Buttonbush is known for its extremely easy care requirements and its hardy nature, meaning there aren’t many problems growing these plants. The biggest problem is too little water.
- Leaves Falling Off or Wilting
Leaf loss or wilting is a sign of drought. Because these shrubs grow near sources of water or in very wet soils, too little water can be a big problem. Be sure to increase the amount of water the plant receives. Alternatively, you may want to relocate the plant to an area that receives consistently more water, such as next to a pond or river.
III. Uses and Benefits
- Medicinal uses
Cephalanthus occidentalis has a number of historical medicinal uses, but it is also toxic due to the presence of cephalanthin.
- Ornamental uses
Gardeners cultivate common buttonbush in pollinator gardens, as its nectar and pollen attract honey bees and butterflies. Its seeds can also be used to entice shore and water birds to the yard. The unusual globe-like blossoms provide an interesting ornamental contrast in areas with wet soil, especially water gardens. Common companion plants included Winterberry, Red maple, and Wild iris.
- Wildlife uses
Waterfowl and other birds eat the seeds. Wood ducks utilize the plant as nest protection, and mallards eat the fruit. Deer browse the foliage, which is poisonous to livestock. Insects and hummingbirds take the nectar, with bees using it to make honey. It is a larval host to the hydrangea sphinx, the royal walnut moth, and the titan sphinx.
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