Barberries (Berberis spp. and Mahonia spp.) are evergreen, semievergreen or deciduous shrubs prized for their attractive foliage and red, purple, blue or black berry-like fruits that draw birds. Multiple available growth habits make these shrubs appropriate as groundcovers, screens barriers or hedges and although the growing range varies, most species thrive within U.S. Department of Agriculture plant hardiness zones 4 or 5 to 8 or 9. Providing a barberry with an adequate, though not excessive, amount of water using appropriate methods helps to encourage shrub vigor and health.
Push a smooth rod with a 1/4- to 3/8-inch diameter into the soil near the barberry's dripline, the imaginary line on the ground that reflects the edge of the shrub's canopy. If it cannot penetrate more deeply than 3 to 4 inches, plan to water the barberry shrub.
Water the soil several inches away from the base of the barberry or at its drip line gently, using a slow trickle from a hose or other watering implement like a watering can or bucket. Apply the water slowly enough that it soaks into the soil without running off atop the soil surface.
Push the smooth metal rod into the ground near the barberry after watering, noting the depth at which it becomes more difficult to force downward. This indicates the depth to which the water penetrated and should reflect the estimated depth of the barberry shrub's root zone, which is approximately 12 to 24 inches, depending on the age and size of the shrub. If the metal rod only penetrates a few inches, irrigate the shrub more; if it penetrates deeper than the estimated root zone, water the shrub less deeply during subsequent waterings to avoid wasting water.
Spread an organic material mulch such as shredded leaves, wood chips or well-rotted compost in a layer 2 to 3 inches thick around, though not directly in contact with, the base of the barberry. A mulch layer helps to conserve soil moisture and suppress weeds that would compete with the shrub for water.
Monitor the barberry for symptoms of underwatering or overwatering. Inadequate moisture can cause leaf yellowing, wilting and drop. Excessive watering or poor drainage causes leaf wilting or yellowing and root death and rot; edema, blisters or tan, corky bumps on leaf surfaces, may also develop. Adjust the frequency and volume of irrigation, if needed.
Things You Will Need
- Smooth metal rod with 1/4- to 3/8-inch diameter
- Hose or other watering implement
- Organic material mulch
- Whenever possible, water the barberry plant in early morning or in the evening to reduce water loss through evaporation.
- Avoid using sprinkler irrigation to water the barberry or inadvertently wetting the foliage, as this can encourage disease and leave unsightly white salts on the foliage.
- University of California Statewide Integrated Pest Management Program: Mahonia, Barberry, Oregon grape— Mahonia, Berberis spp.
- The University of Arizona Cooperative Extension: Watering Trees and Shrubs
- University of California Sonoma County Master Gardeners: Berberis
- University of Florida IFAS Extension: Berberis Thunbergii Japanese Barberry
- University of California Statewide Integrated Pest Management Program: Poor Water Management, Poor Drainage
- Hemera Technologies/AbleStock.com/Getty Images