Sweetshrub

Prepared by Karen Russ, HGIC Horticulture Specialist, Clemson University. (New 2/10.)

HGIC 1087

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Sweetshrub (Calycanthus floridus) has many common names, including Carolina allspice, strawberry-bush, sweet bubby, sweet Betsy and spicebush. As these names indicate, it is valued for the sweet, often fruity fragrance of its flowers. Sweetshrub is native along the east coast from Pennsylvania south to northern Florida and west to Mississippi. In South Carolina it is native in the Upstate and Central regions, and grows well throughout the state.

Sweetshrub blossom opening
Sweetshrub blossom opening.
Karen Russ, ©2010 HGIC, Clemson Extension

Mature Height/Spread

Sweetshrubs grow 3 to 9 feet tall by 6 to 12 feet wide. Plants grown in full sun will be shorter than those grown in part shade. Sweetshrubs have a dense, broad, rounded form in cultivation. They are multi-stemmed shrubs that tend to spread widely by growing new shoots (suckers) along the outer edges of the clump. Wild plants are much more open, tall, and even scraggly.

Growth Rate

Plants grow at a moderate rate of 12 to 18 inches per year under ideal growing conditions of deep, moist, loamy soil and with partial shade. Growth rate will be much slower in dry soil and full sun.

Ornamental Features

Dark, reddish brown to wine-red flowers open in April to May, with occasional scattered flowers appearing during summer. They are 1 to 2 inches wide, shaped somewhat like magnolia blossoms, and are produced abundantly.

Sweetshrub flowers have a sweet, fruity scent often described as pineapple, strawberry, melon, banana or bubble gum. Scent is highly variable from plant to plant, and some have little fragrance or even an objectionable odor. To ensure a pleasantly-scented plant, either buy while in bloom, propagate by cuttings from a fragrant plant, or purchase a named cultivar known for good fragrance.

Flowers are long lasting on the shrub and also make good cut flowers. They can also be dried and added to potpourri. All other plant parts are fragrant also, with the leaves, seed pods and bark having a spicy scent when crushed.

Sweetshrub leaves are relatively large, from 4 to 6 inches long and 2 to 3 inches wide, and are arranged oppositely along the stems. During summer they are a lustrous, dark green, and then turn golden-yellow before falling in autumn.

Golden-yellow fall color of sweetshrub foliage
Golden-yellow fall color of sweetshrub foliage.
Joey Williamson, ©2010 HGIC, Clemson Extension

Seed pods are irregularly urn shaped, 1 to 2 inches long and green, turning brown in fall when mature. There are numerous seeds inside.

Immature sweetshrub seed pod will turn brown when ripe.
Immature sweetshrub seed pod will turn brown when ripe.
Karen Russ, ©2010 HGIC, Clemson Extension

Pods often persist throughout the winter and/or into the following spring. The seeds are poisonous, but only if eaten in large quantities. They do not have an appealing edible appearance.

Landscape Use

To take full advantage of the fragrance, sweetshrubs are often planted near entrances, or other outdoor living areas. They can also be used in shrub borders and native plant gardens.

Sweetshrub naturally grows as an understory shrub in mixed deciduous forests, along streams and in moist woodlands. Although it is easy to grow and adaptable, it’s ideal growing conditions are similar to those of its native habitats. For best results, plant sweetshrub in moist, well-drained, loamy soil, ideally in dappled or part shade. It is not salt tolerant.

Maintenance is easy. If pruning is needed, do so immediately after flowering to shape or maintain compactness. Plants spread by suckering and if width needs to be reduced, remove outer suckers as they emerge.

Sweetshrub is easy to transplant, ideally during the fall or winter after leaf fall. Rooted suckers can also be detached from the main plant and replanted.

Plants can be propagated by seed, but be aware that seedlings may vary from the parent plant in scent and other characteristics. Collect seeds in fall as pod color changes from green to brown. Seeds from older pods rarely sprout. Either plant seeds immediately in an outdoor bed, or store seeds in a refrigerator for 3 months before planting.

Seed pods often hang on plants through the winter.
Seed pods often hang on plants through the winter.
Joey Williamson, ©2010 HGIC, Clemson Extension

Cultivars vary in how well they root from cuttings. However, cutting grown plants have the advantage of retaining the features of the parent plant. For best results, take cuttings in July, lightly scrape the cuttings on one side and dip in talc-based rooting material. Place cuttings in sand or a sandy rooting media.

Removing and transplanting suckers from parent plants is an easy way to obtain new true to form plants. Almost all will root well if given adequate moisture during establishment.

Problems

Sweetshrubs have no serious insect or disease problems. Phytophthora or Pythium root rots can occur in very poorly drained soil.

Cultivars

  • 'Athens' is a selection with yellow-green, highly fragrant flowers. Although the flowers are beautiful up close, they do not show well against the foliage from a distance. This plant is ideally appreciated at close range, near a doorway or beside a patio bench.

Pale yellow-green flowers of Athens sweetshrub
Pale yellow-green flowers of ‘Athens’ sweetshrub.
Joey Williamson, ©2010 HGIC, Clemson Extension

  • 'Michael Lindsey' is one of the best cultivars available. Dark flowers are exceptionally fragrant, and foliage is darker and shinier than the species. Its form is dense and compact. Fall color is reliably bright yellow.
  • 'Hartlage Wine' is a hybrid between Calycanthus (syn. Sinocalycanthus) chinensis and C. floridus. Flowers are 3 inches wide, maroon to wine colored, with wide petals and a light fragrance. It grows larger and more upright than most sweet shrubs, at least 8 feet tall by almost 8 feet wide to 15 feet tall by 10 feet wide.
  • ‘Venus’ is another new hybrid with even more complicated parentage of C. chinensis C. floridus and C. occidentalis. The results are spectacular – ivory yellow buds open to 3-to 4 ½-inches wide, fragrant, white flowers with yellow and purple centers. Plants grow 6 to 10 feet tall and wide.

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