Sweet shrub, also called Carolina Allspice, is a low-maintenance, deciduous shrub that is hardy to plant in USDA growing zones 4 through 9. The shrub grows best in a fertile soil that is well draining and makes a great border plant or edge for a wooded area. Sweet shrub is not attractive to deer and can be planted on a slope.
The sweet shrub is a deciduous plant that has glossy, dark-green foliage with a leathery feel. Sweet shrub stands upright at a height of 6 to 12 feet with multiple stems growing off the base. The terminal blossoms are dark red in color, 1 1/2 inches wide, have a fragrant scent and bloom in early to mid summer. Sweet shrub foliage turns yellow during the fall season.
Sweet shrub grows best when planted in a well-draining soil such as sandy loam or clay loam and full to partial sunlight. People in warmer climates should plant sweet shrub in a partially shaded location to prevent sun scald. The soil should be tested prior to planting to verify it is acidic with a pH of 5.5 to 7.0. Ground rock sulfur can be worked into the soil two weeks or more prior to planting to lower the pH number.
The sweet shrub prefers a moist soil and should be given supplemental water during the hot summer months and periods of drought. Supply water when the weekly rainfall amounts are less than 1 inch by giving the plant a deep soaking to a soil depth of 8 to 10 inches. Place a layer of mulch around the shrubs to retain soil moisture. Fertilize the shrubs each spring with a balanced fertilizer. Do not apply fertilizer in the fall as this will force growth that will not harden before the cold winter temperatures.
Sweet shrub can be propagated to produce additional plants by taking semi-hardwood stem cuttings in late summer through early fall. Semi-hardwood cuttings are taken from current year growth that is woody and beginning to mature. The stems will produce roots when stuck into moist rooting medium and placed in a warm location with indirect light. The cuttings can be transplanted into individual growing containers once the roots reach 1 inch in length.
The sweet shrub is susceptible to the bacterial disease crown gall, which forms wart-like growths on the lower stem of the shrub. There is no treatment for crown gall except complete removal. The soil will remain contaminated and should not be planted in for two or more years.