Soil pH for Black Hardy Mulberry Trees

Characteristics

• Black mulberries are the smallest of the mulberry species, reaching 30 feet in height. They are often treated as bushes in the landscape when they are not pruned to a single trunk. Their leaves are thick, blunt-toothed and lobed in shape. They have smaller twigs and plumper buds than the other two mulberry varieties. The black mulberry sets catkins in early spring that develop into the berries. They set fruit that is long and cylindrical like a loganberry, with an appealing balance of sweet and tart taste. Black mulberry fruit ripens over a long summer period, rather than all at once like many fruits. All mulberry species are wind pollinated and some species are able to set fruit with no pollination at all.

Soil Needs

• Black mulberry trees prefer warm, well-drained, deep-loam soil with a pH range of 5.5 to 6.5. Deep loam soil is composed of equal parts sand, silt and clay to a depth of 36 inches. Sand particles allow aeration; clay contains mineral nutrients and keeps water in; and silt has water-holding capabilities between the two. Slightly acidic soil has a higher organic matter content than alkaline soil.

Adjust Soil pH

• Soil pH affects the availability of nutrients for plant growth and health. The recommended pH level for black mulberry trees indicates the acid-alkaline level at which the tree can absorb nutrients from the soil. Mulberries and all plants require nutrients from soil, water and air to grow and thrive. These necessary nutrients are absorbed most effectively by mulberry roots when the pH range is 5.5 to 6.5. Aluminum sulfate and sulfur are often added to soil to make it more acidic and lower its pH. Aluminum sulfate lowers pH immediately, but sulfur requires time for bacteria to transmute it and lower the pH. Adding a total of 3.3 pounds of aluminum sulfate for each 10 square feet changes a pH rate of 8.0 to 5.5.

Culture

• Black mulberries are prized for their sweet, flavorful taste. They are generally free of pests and diseases, although some canker and dieback can occur. Black mulberry fruits ripen in late summer and early fall. They are more difficult to harvest than white or red mulberries because the fruit collapses easily when they are pulled off the tree.