Calycanthus

( kal - ik - KANTH - us )

At-A-Glance Information

Calycanthus, commonly called Carolina Allspice or Sweetshrub, is a genus of deciduous shrubs that can grow in either sun or shade. They need regular waterings. Sweetshrub should not be confused with Pimenta dioica, the plant that the edible culinary flavoring Allspice is harvested from. These shrubs are bulky, with lush foliage and flowers that are valued for their fragrance and form. Many parts of these plants are used in dried form in potpourri. They do not take well to hard pruning, so ensure that you choose a species that will fit into your yard without much controlling for size. Use Calycanthus shrubs in mixed beds and borders, as specimens, or to add fragrance to different areas of the garden. Care should be taken when planting these shrubs in your garden, as the seeds can produce toxic reactions in humans and pets if ingested.

Calycanthus Species and Varietals

The genus Calycanthus includes just two species of deciduous shrubs, and is a member of the family Calycanthaceae. The genus was first formally described by Carl Linnaeus in 1759, and at the time included only one species, Calycanthus floridus. In 1762, the separate species Calycanthus praecox was added to the genus. Growing zones for Calycanthus vary by species, so please refer to the following descriptions for more information. To find your zone, click here: Zone Map.

Calycanthus floridus (Carolina Allspice, Sweetshrub, Sweet Bubby, Sweet Betsy, Spicebush)
This shrub grows best in USDA hardiness zones 4-9 or Sunset growing zones 3-9 and 14-17, and is native to an area that spans between Virginia and Florida. Branches are stiff, and the plant reaches around 6-10 feet tall and wide at maturity. It has a suckering habit and spreads quickly. Leaves are a glossy dark green on top, greyish green underneath. Flowers are reddish brown with a strawberry-like fragrance. Blooms are present in late spring or early summer and are followed by pear-shaped seed capsules that are very fragrant when crushed.

'Aphrodite'
With reddish-purple and creamy white blooms.

'Athens'
With yellow-green flowers.

'Burgundy Spice'
Compact with maroon foliage and red flowers.

'Hartlage Wine'
Produces burgundy-red and white blooms.

'Michael Lindsey'
Compact shrub with dark maroon flowers.

'Venus'
Hybrid with cream-white and rose colored blooms.

Calycanthus occidentalis (Spicebush, California Sweetshrub, Western Spicebush, Western Sweetshrub, California Allspice)
Grows well in USDA hardiness zones 7-9 or Sunset growing zones 4-9 and 14-24. Native to stream banks and moist slopes in California's Coast Range and Sierra Nevada foothills. Can reach 4-12 feet tall and just as wide. Leaves are bright green, and turn yellow in fall. Flowers are brownish red and look like small water lilies. Flowers and bruised leaves have the smell of old wine barrels. This species can be trained to be a multi-stemmed small tree, but is most useful in the garden as a backdrop shrub.

Caring for Calycanthus

Care should be taken when planting these shrubs in your garden, as the seeds can produce toxic reactions in humans and pets if ingested. Plant Calycanthus in a space in the landscape that receives full sun or partial shade; ideally, they appreciate between 6 and 8 hours of sun each day for the best blooms. In areas with cool winters, plant in a sunny location. When these flowers are grown in less light, they will not flower as profusely. Ensure that soil is well-draining, rich in nutrients, and has a pH of between 5.5 and 8.0 (slightly acidic to neutral). If local soils are particularly poor in nutrients or do not drain well, make sure to amend the planting area with plenty of organic compost before installing. Apply a layer of mulch around the planting area to suppress weed growth, maintain consistent soil temperatures, and to increase soil moisture retention. Water new plantings regularly as they establish a strong root system in their new home. At maturity, Calycanthus shrubs appreciate consistently moist soil during active growing and flowering periods.

Fertilize yearly in early springtime with an application of 2 inches of compost around the base of plants. Pull mulch back before applying, work the compost gently into the soil a bit, water it in, and then replace mulch. These shrubs do respond well to pruning in late fall or early springtime; they can be pruned to control for size, to take out suckers at the base, and to maintain a few main branches (so the plant doesn't get too tall or unruly). Calycanthus is sensitive to freezing temperatures; use a frost cloth during the cooler months of the year in areas that experience freezing temperatures. Sweetshrub is a long-lived perennial, lasting for 20-50 years in the landscape before needing to be replaced.

Caring for Calycanthus in Containers
Calycanthus shrubs are wonderful in the ground, but can also be grown in containers. Choose a container that is at least a few inches wider and deeper than the nursery pot or root ball. Ensure that the pot has adequate drainage holes on the bottom to allow for excess water to flow away. Fill with a well-draining potting mix amended with organic material and perlite, and top with a layer of mulch to suppress weed growth, maintain consistent soil temperatures, and to increase soil moisture retention. Water regularly as the plant establishes itself in its new home. Once established, waterings can be lessened. Sweetshrub plants grown in containers will need more frequent irrigation than those grown in the ground. As a general rule of thumb, water whenever the top inch of soil feels dry to the touch. Prune to remove dead, damaged, or diseased foliage at any time during the growing season. Every two to three, check the bottom of the pot to ensure that the plant is not outgrowing its root space. If roots are growing through the drainage holes in the bottom of the container, it is a good indication that it needs to be potted up; choose a slightly larger container and repot.

Propagation

The easiest way to propagate Calycanthus shrubs is by separating and transplanting volunteer plants grown through suckers at the bottom of an existing plant. Simply dig up your chosen sucker and replant it elsewhere in the garden in springtime. These plants can also be propagated via cutting. Your propagated plant will have the exact same qualities and characteristics as the parent plant, and it is a relatively simple process. Follow the steps listed below to propagate your Calycanthus through cutting.

Propagating Calycanthus by Cutting

Gather your materials. You'll need a clean, sanitized, sharp pair of garden shears, rooting hormone, a pencil, and a 3-inch pot filled with well-draining compost or other organic material. A good substrate for propagation of cuttings is a light blend of 1/3 pasteurized soil or compost, 1/3 sand, vermiculite or perlite, and 1/3 coconut coir or peat moss.
In summertime (July is one of the best months for this), before the plant has had time to harden its current season's growth, choose your plant that you'd like to propagate. Ensure that this plant has had a good watering the night before, as this will improve the chances your cutting will take root. Cut one or more 4-6 inch portion(s) of the end of a non-blooming branch and strip off all of the lower leaves, leaving the top two on the cutting. Make a hole in your planting medium by pushing your pencil into the soil. Dip the end of the stem in rooting hormone, and plant it in your pot.
Moisten with water, and ensure that the pot has good drainage. Your pot should be kept in cool, sunny conditions indoors (and not in direct sunlight). Water whenever your soil is dry under the top layer. After about four to six weeks have passed, your cutting should be rooted. When you notice new growth on your propagated plant, you'll know you have roots.
Keep your new plant in an area with bright light (though not direct sunlight) and temperatures between 55 and 70 degrees Fahrenheit. Ensure that the soil stays moist, but not wet, until the next spring, when you can transplant your Calycanthus to its new home.