You don’t often see Carolina allspice shrubs (Calycanthus floridus) in cultivated landscapes, possibly because the flowers are usually hidden beneath the outer layer of foliage. Whether you can see them or not, you’ll enjoy the fruity fragrance when the maroon to rusty brown flowers bloom in mid-spring. A few of the cultivars have yellow flowers. The foliage is also fragrant when crushed. Both the flowers and leaves are used to make potpourris; and in the past, they were used in dresser drawers and trunks to keep clothes and linens smelling fresh.
I. Appearance and Characteristics
Calycanthus floridus, or commonly known as the eastern sweetshrub, Carolina all spice, or spicebush, is a species of flowering shrub in the family Calycanthaceae. It is identifiable by its dark red flowers and fragrant scent. It is non-invasive and is found in the Southeastern United States region. The Nature Conservancy considers its conservation status to be G5, globally secure, indicating it is at low risk of extinction. It is presumed to have been extirpated from Ohio.
Calycanthus floridus was first scientifically described by Carl Linnaeus in 1759. It was the only species in his new genus Calycanthus. Linnaeus referred to an earlier illustration by Mark Catesby, contained in a work published from 1731 onwards.
Calycanthus floridus is a shrub that grows to be around 6 to 9 ft (2 to 3 m) tall. Its leaves are a dark green with a pale underside. They are ovate or elliptical in shape and grow to be about 6 inches (15 cm) in length. The leaves are simple, entire, and arranged oppositely along the stem.
The flowers are solitary, featuring a reddish brown to reddish purple color when they bloom in spring. They are aromatic and so are the leaves when bruised. The flowers have a hypanthium that is more than 2 cm (0.8 in) long. The shape of the flowers can be cylindrical, ellipsoid, pyriform, or globose. The flowers have numerous sepals that can either be oblong-elliptic or ovate-lanceolate at maturity. The flowers are perfect, having both stamens and carpels on the flowers. The stamens are numerous, connective beyond the anthers. The carpels are numerous. They are free, with a single ovary in a locule.
The fruits are indehiscent pseudo carbs that are about 8 cm (3 in) in length and 5 cm (2 in) in diameter at maturity. They are formed within the receptacle and contain numerous achenes that are roughly 10 mm (0.4 in) long with a 5 mm (0.2 in) diameter.
II. How to Grow and Care
This is a versatile shrub that works well in the landscape as either a specimen or hedge planting, requiring fairly minimal care to remain attractive. It is what’s known as an “understory” shrub, meaning it grows well in the shade of larger trees.
Sunlight
Carolina allspice is flexible in terms of its light needs and is suitable for both sunny and shady spots. The plant will benefit from a good amount of sun in the winter in colder growing zones.
Temperature and Humidity
This shrub can be grown in warm zones (up to 10a) and does well growing near waterways, so it makes a nice specimen alongside ponds or creeks. Some winter protection can help Carolina allspice stay healthy and vibrant in colder growing zones.
Watering
Carolina allspice plants are accustomed to moist climates. Water enough to keep its soil moist, replenishing hydration whenever the surface of its soil dries out. Water deeply to help encourage root growth.
Soil
Carolina allspice is tolerant of a range of soils, making it adaptable to most gardens. It does need good drainage, however, so if you have heavy clay soil, you will want to add some amendments such as peat moss, manure and compost. Acidic or alkaline soils are both suitable for growing this plant.
Fertilizing
Feed your carolina allspice when planting or transplanting, and every spring thereafter, with a generous helping of good-quality compost or balanced fertilizer. Dig as deeply into the soil as you can without disturbing your plant’s roots. Water well immediately after fertilizing.
Pruning
The Carolina allspice responds well to pruning. Although it grows quite tall and wide if left unpruned, it can also be trimmed to accommodate your preferences and your available space. If you want to use it as a specimen planting, keep it trimmed so that a small number of branches form its main shape, and trim new shoots as they appear at the base. The best time for pruning is late fall or early spring.
Propagation
You can grow your own shrub from cuttings but it’s best to start out with a purchased plant. Once your original plant matures, offshoots will begin to grow plentifully from the base and can be removed to start new plants.
- Keep the root system intact on the offshoots when you dig them. Replant right away in a chosen spot or plant in pots.
- If you are using cuttings, remove a 4 to 6 inch branch and remove any lower leaves.
- Use rooting hormone powder and loamy soil, and keep the cuttings moist after planting.
- Covering the cutting with a plastic bag can help keep it moist while it forms roots, but open the bag once a day for at least an hour to prevent mold growth; or try dispensing with the plastic and mist the shoots lightly once per day.
- The shoots should form roots in about 7 to 8 weeks. Wait until there is some new leaf growth before transplanting.
How to Grow from Seed
This is a somewhat longer term project, as you must collect and start seeds in fall and plant the new seedlings out in spring.
- Collect seeds from the seedpods after blooms fade and pods are full. Let the seeds dry thoroughly.
- Clean plant debris from the seeds before planting in loamy soil ¼ inch deep.
- Keep soil moist and put trays or pots in a sunny window.
- Transplant outside in spring after the danger of frost has passed.
Overwintering
If you live in a growing zone below 5b, your Carolina allspice may not flourish without winter protection. Frozen ground can damage the roots so a late season application of mulch or pine straw at the base of the shrub is recommended. Planting in a sunny spot or near a structure, such as brick or stone, that holds heat will also provide some protection in colder climates.
Potting and Repotting
This shrub can be grown in a large container that has good drainage. It should be repotted every 2 to 3 years so that the roots don’t get too crowded.
Pests and Diseases
Common Pests and Plant Diseases
Carolina allspice can be susceptible to bacterial crown gall, which is recognized by a bumpy, warty growth where the plant meets the soil. There is no treatment for this disease and the shrub should be removed and destroyed. Avoid planting in the same spot since bacterial crown gall will contaminate the soil where a diseased plant has been grown.
Common Problems
Like tall garden phlox, Carolina allspice is susceptible to powdery mildew. The best solution to this problem is making sure the plant has adequate air circulation, so when planting, give it space to grow where it won’t bump up against other plants. Thinning the growth by careful pruning can also be beneficial.
Carolina allspice may be susceptible to common, small, sap-sucking insects like aphids and white flies. A strong spray from a garden hose or an application of insecticidal soap will usually resolve any problem. Bark beetles, that burrow into the trunk and branches, may also find their way to your shrub. Prune away any visibly damaged wood to keep your shrub healthy and thriving.
III. Types of Carolina Allspice
Like many popular plants for the garden and landscape, Carolina allspice is also offered in several cultivars that allow for variety in size and bloom colors. Their names reflect the sweet fragrance of the plant and delicately beautiful flowers.
- ‘Aphrodite’ – A nice dwarf cultivar (4 to 6 feet) with bright crimson flowers that have a light citrus fragrance.
- ‘Athens’ – Yellow-chartreuse flowers and good yellow fall foliage coloration.
- ‘Burgundy Spice’ – Vivid burgundy colored blooms and leaves, excellent fragrance.
- ‘Venus’ – Compact size, all-white blooms with a fruity fragrance in the spring blooms that some have compared to bananas.
IV. Uses and Benefits
- Garden Use
As a specimen tree, carolina allspice grows tall and wide in partial shade. But it can also be cultivated in full sun, resulting in a shorter, more dense shrub suitable for hedges. Florists keep this plant for its greenery, which goes well in cut arrangements. It will even add color interest in autumn, when those leaves turn bright yellow. It combines beautifully with Hydrangeas.
- Human Uses
The dried bark of this plant has reportedly been used as a cinnamon-like spice, although the plant is known to be mildly toxic, so caution is advised. Various traditional medicinal uses are reported, as well as uses in perfumes and flower arrangements.
- Wildlife Uses
This bush provides nesting sites and shelter for birds and other small animals. The flowers attract small beetles, which are responsible for pollination.
