Sweetbay

Scientific Name: Magnolia virginiana L.

Sweetbay

General Information
Usda Symbol	MAVI2
Group	Dicot
Life Cycle	Perennial
Growth Habits	ShrubTree,
Native Locations	MAVI2

Plant Guide

Alternate Names

Common Names: sweetbay magnolia; laurel magnolia; swamp magnolia; small magnolia; swamp-bay; white-bay Scientific Names: Magnolia virginiana L. var. australis Sarg.; Magnolia virginiana L. var. parva Ashe

Description

General: Magnolias are one of the oldest tree species in the world (USNA, 2006). Sweetbay is a woody, flowering, native tree that can grow up to 60 ft (grows only to 20–40 ft in the North) on multiple gray and smooth stems (Dirr, 1998; Gilman and Watson, 2014). It may be deciduous, semi-evergreen, or evergreen; and will be deciduous in its furthest northern extent. It grows similar to a shrub, with a short, open habit. It can live over 50 years. It has slender, hairy twigs, and the gray or light brown bark has scales that are pressed together. The bark is aromatic when crushed. Sweetbay is similar in appearance to southern magnolia (Magnolia grandiflora), but it has a smaller circumference and shorter height than the latter. The 4–6 in (10–15 cm) long, 1–3 in (3–8 cm) wide leaves are simple, alternate, oblong, toothless, slightly leathery, with a wedge-shaped base and bluntly point apex. Like southern magnolia, the leaves are lustrous above and pubescent below, however sweetbay is silvery below, while southern magnolia has a rusty red pubescence (tomentum). The petiole is approximately ½ in long (Dirr, 1998). In late spring (May–June) it produces 2–3 in (5–8 cm) wide fragrant white, 9–12 spoon-shaped petaled, monoecious flowers (having male and female reproductive organs on same plant) on slender, smooth stalks. The flowers are pollinated by beetles, and open and close in a 2-day flowering cycle, alternating between a female and male pollination phase. These separate phases prevent the flower from self-pollinating, however, separate flowers on the same plant may cross-pollinate (Losada, 2014). The flowers are reported to produce a lemon scent and when the flowers close they generate heat that is beneficial to the beetles. (Bir, 1992; Losada, 2014). The fruit is an aggregate of dry, cylindrical, hairy, 2 in long (5 cm) carpels. Each follicle contains one 1/4 in (0.6 cm) long bright, oval red seed. The seed remains attached to the open pod by a thin, elastic thread. Distribution: Magnolias once made up a large part of North Temperate forest trees before the last glacial period (Maisenhelder, 1970). Sweetbay grows along the Atlantic and Gulf Coastal Plains from Massachusetts south to Florida, west to Texas, and north to Tennessee. Sweetbay can be grown in USDA hardiness zone 5b–9 but can also be grown in lower Midwestern states such as Ohio and Indiana (Dirr, 1998). For current distribution, please consult the Plant Profile page for this species on the PLANTS Web site. Habitat: Sweetbay extends farther north than southern magnolia and it is designated as a USDA facultative wetland plant which means it usually occurs in wetlands. It will be found in wet, sandy, acidic soils along streams, swamps, and flatwoods (Elias, 1980). It occurs in pine and hardwood forest, flatwoods, and floodplains (Gucker, 2008). It often grows in the sweetbay/swamp tupelo/red maple forest complex and is associated with black, water, and swamp tupelo (Nyssa sylvatica, N. aquatica, N. biflora), sweetgum (Liquidambar styraciflua), water and willow oaks (Quercus nigra, Q. phellos), white and green ash (Fraxinus americana, F. pennsylvanica), black willow (Salix nigra), and red maple (Acer rubrum) (Maisenhelder, 1970). It also dominant in bay forests with redbay (Persea borbonia) and loblolly-bay (Gordonia lasianthus) (Gucker, 2008). The soils in these habitats can be organic, acidic, sandy, saturated, nutrient-poor, peaty, or mucky. The soils can be Ultisols, Spodosols, and Coastal Plain Histosols (Priester, 2004). It grows larger in the Southeastern US where soils are richer and wetter (Elias, 1980). It is considered a climax species in many forest communities.

Adaptation

Magnolia spp. are native to Southeast Asia, eastern North America, South and Central America, and the Caribbean (Knox et al. 2013). Under natural conditions, sweetbay seedlings grow in shady to partly-shady hardwood or Natural Resources Conservation Service Plant Guide coniferous forest understories. Sweetbay is different from other magnolias in that it can tolerate saturated and flooded soils as well as droughty conditions. It has been shown to survive flooding and severe drought without significant loss of root mass (Gilman and Watson, 2014; Nash and Graves, 1993). It is adapted to lower elevations less than 61 m (200ft) above sea level (Priester, 2004). It grows best in warm climates and acid soils, and is deciduous north of USDA Hardiness Zone 8 and may exhibit some winter damage in the northern part of USDA Hardiness Zone 5 (Dirr, 1998). Sweetbay is resistant to fire and can recover from top-kill due to fire, resprouting from root crowns, roots, and lignotubers (Gucker, 2008; Priester, 2004).

Uses

Timber/wood: Sweetbay does not have a significant value as a timber source, however like southern magnolia, it is used for furniture, cabinets, paneling, veneer, boxes, and crates (Hodges et al., 2010). It is straight-grained, can be easily worked, and takes finishes well (Elias, 1980). Ornamental/landscaping: Sweetbay is valued for its beauty, open form, attractive leaves, and its fragrant flowers (Hodges et al., 2010; Losada, 2012). It works well in a shrub border or as a single specimen and can be planted next to buildings or in situations with restricted space due to its horizontal crown (Gilman and Watson, 2014). It would be a good choice for rain gardens because it can tolerate saturated soils (Feather, 2013). Currently, it is not as popular as southern magnolia for use in urban settings but has potential for greater use (Gilman and Watson, 2014). Wildlife: Magnolia seed ripens in mid-Autumn and is eaten and spread by songbirds, wild turkey, quail, and mammals such as gray squirrels and white-footed mice. Seeds are high in fat and are a good energy source for migratory birds (USNA, 2006). They are eaten by eastern kingbirds, towhees, mockingbirds, northern flickers, robins, wood thrushes, blue-jays, and red-eyed vireos (Arnold Arboretum, 2011; Feather, 2013). Sweetbay is also an important plant for attracting hummingbirds (KCPD, 2007). Pollinators, especially beetles, are attracted to the pollen that is high in protein. It is a host plant for tiger swallowtail butterfly, palamedes swallowtail, spicebush swallowtail, and sweetbay silkmoth (Nitao et al., 1992; Gilman, 2015; NPIN, 2014). Deer and cattle often browse the leaves. The leaves can contain up to 10% crude protein content and can account for 25% of a cattle’s browse in winter (Hodges et al., 2010; Priester, 2004).

Ethnobotany

William Bartram (1739–1823) often wrote about sweetbay in the Southeast due to its natural beauty and importance to indigenous tribes (Austin, 2004), The leaves were used as a spice in gravies and tea was made from the leaves and/or bark (Fern, 2010), It was used by physicians in the 18th century to treat diarrhea, cough, and fever, used by the Rappahannock in Virginia as a stimulant, and the Choctaw and Houma used it as a decoction to treat colds (Austin, 2004), It was also used to treat rheumatism, gout, malaria, and was even inhaled as a mild hallucinogen (Fern, 2010; Speck et al,, 1942; Grandtner, 2005), , Use soil moisture sensors to measure the soil moisture of Sweetbay.

Status

Weedy or Invasive: There are no known problems with magnolias becoming weedy and there is no indication that sweetbay seed persists in the seed bank (Gucker, 2008). Please consult with your local NRCS Field Office, Cooperative Extension Service office, state natural resource, or state agriculture department regarding its status and use. Please consult the PLANTS Web site (http://plants.usda.gov/) and your State Department of Natural Resources for this plant’s current status (e.g., threatened or endangered species, state noxious status, and wetland indicator values).

Planting Guidelines

Magnolias are moderately fast-growing trees that are easy to grow. Sweetbay may be propagated through bare root, stem cuttings, and grafts. It can be grown in containers and transplanted into the field in late winter/early spring with a mulch to moderate soil temperature and moisture (USNA, 2006). Seed can be collected in fall, soaked in water and baking soda for several days (to prevent fermentation), de-pulped, and stored for 3 months at 45°F for the requisite period of cold-stratification (MFC, 2007). Afterwards, it can be directly planted in a well-prepared seedbed in early spring. In natural forest communities sweetbay seedlings have highest survival rates when planted in large openings that are not flooded for long periods (Priester, 2004).

Management

Container-grown plants should be transplanted in spring or fall, mulched, fertilized at planting, and well-watered. Sweetbay seedlings have greater success when grown in part-shade for the first year of establishment (Priester, 2004). Applying ½ lb of 10-10-10 fertilizer at the base of the tree in March, May, and July during the first year of establishment will accelerate growth (Wade, 2012). Avoid fertilizing the tree during its slowest time of growth in fall and winter. Continued watering and mulching is required for successful establishment, and many projects with Magnolia spp. have failed due to desiccation (MFC, 2007). Sweetbay has a natural conical form and should be pruned to this shape. It may grow from several trunks, so if a single trunk in desired, prune the tree around a central leader. When sweetbay is pruned in more northern latitudes, it can “fill-out” and be more shrub-like in appearance. Plants may be coppiced (Hodges et al., 2010). Fallen leaves create a persistent residue and can be raked under the tree and used as mulch. If there is evidence of leaf spot on the fallen leaves, those leaves should be raked up and disposed (Gilman and Watson, 1994). In natural