Carolina allspice ( Calycanthus floridus), also known as spice bush or sweet shrub, is native to the Southeast U.S. where it is commonly grown in home gardens. Carolina allspice should not be confused with the plant that produces allspice, the sweet culinary spice added to baked goods, which comes from the berries of the plant Pimenta dioica. The Carolina allspice shrub is easy to grow and hardy in a wide range of growing zones. It grows up to 9 feet) tall, spreads up to 12 feet wide, and can be easily pruned and trained as a hedge. A strong branching system will withstand high winds, which makes this shrub useful as a windbreak for less hardy plants that require winter protection.
The flowers, which are actually sepals that grow together in a floral formation, are often hidden by the leaves. Their intoxicating fruity perfume will let you know the shrub is in bloom. The leaves are also fragrant if crushed, and the bark has a distinctly camphor or juniper-like scent. All parts of the plant were traditionally placed in drawers and closets to keep linens and clothing smelling fresh. More recently, the plant has become popular for use in potpourri.
Carolina allspice blooms are usually a dark red or maroon to brown color (although some cultivars produce yellow, pink or white flowers). There is a West Coast species (C. accidentalis) that grows even taller (up to 15 feet) and the flowers tend more toward bright red.
|Botanical Name||Calycanthus floridus|
|Common Name||Carolina allspice, sweet shrub, spice bush|
|Plant Type||Flowering shrub|
|Mature Size||6-9 ft. tall|
|Sun Exposure||Full sun to shade|
|Soil pH||Tolerant of most soils|
|Flower Color||Yellow to brown|
|Hardiness Zones||5b-10a (USDA)|
|Native Area||Southeastern United States|
|Toxicity||Berries and seeds are toxic to pets and people|
Carolina Allspice 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.
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.
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.
These shrubs need a moderate amount of water, but extra watering should be necessary only in times of drought. A layer of natural mulch around the base will help conserve moisture.
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.
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.
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.
Propagating Carolina Allspice
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 Carolina Allspice from Seed
This is a somewhat longer term project, as you must collect and starts 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 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.
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.
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 with Carolina Allspice
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.
How long does Carolina allspice bloom?
Since the flowers are not true flowers but sepals, they have a long season of color, from mid spring until autumn.
Is Carolina allspice toxic?
Yes; the berries and seeds can be toxic, so exercise caution if you have pets that like to eat plants.
Can you grow Carolina allspice in USDA zone 4?
Sadly this plant is not cold hardy for all Northeast growing zones, but with winter protection it can grow in Zones 5 and above. You could also try growing it in a container and placing it in a protected place such as a three season porch in winter.
North Carolina State University Extension Office. “Calycanthus floridus” Ncsu.edu. N.p., n.d. Web.