Septic risers are an unattractive necessity for most kinds of septic systems. Shrubs can be planted to help disguise the risers however they need to be planted at least 10 feet from the cylinder the risers are around and the absorption area, if your septic system has one. Drought-tolerant shrubs and shrubs that thrive in dry conditions will be perfect for use about septic risers, as they are not likely to spread invasive roots toward the septic system seeking water. Such shrubs that also blossom may add flowery interest into the septic riser display.
Spring Floral Interest
Fetterbush (Lyonia lucida) and pipestem (Agarista populifolia) are drought-tolerant evergreen shrubs that may be planted as displays with spring flowery interest. Fetterbush shrubs, also referred to as stagger-bush or shiny lyonia, typically grow to a height of 3 to 6 feet and create fragrant pink, white or red flowers. They are hardy in U.S. Department of Agriculture plant hardiness zones 7 to 10 and thrive in dry, sandy soil. Pipestem shrubs, also referred to as Florida hobblebush or Florida leucothoe, grow to a height of 8 to 12 feet and create fragrant creamy white flowers. They are hardy in USDA zones 7 to 9 and grow well in dry soil but prefer supplemental water during dry spells. Both shrubs will grow in full sunlight or partial shade.
Summer Floral Interest
Purple sage (Leucophyllum frutescens) and oleander (Nerium oleander) can be planted for displays that provide summer flowery curiosity; the two shrubs grow in full sunlight or partial shade. Purple sage is a semi-evergreen shrub, hardy in USDA zones 7 to 10. It grows to 3 to 5 feet tall in dry, sandy conditions or 5 to 8 feet tall in garden soil with supplemental water. The foliage may be green, gray-green or silvery flowers and green may be blue, pink, purple or white, depending on the cultivar. It is drought-tolerant and takes fast-draining soil. Oleander is hardy in USDA zones 8 to 10 and grows to 20 feet tall and 10 feet wide with a naturally round shape. The flowers may be pink, red, salmon, yellow or white, depending on the cultivar. It’ll grow in soil that tends to remain moist or dry and is drought-tolerant. But oleander is poisonous if ingested and may lead to skin irritation, so it shouldn’t be planted where kids and pets play.
Fall Floral Interest
Thorny elaeagnus (Elaeagnus pungens) and thryallis (Galphimia glauca) are evergreen shrubs that grow fairly quickly. Thorny elaeagnus, also referred to as silverthorn, grows to 15 feet tall and 20 feet wide with a naturally round shape. It blooms in late fall and early winter, producing small, fragrant white flowers followed by berries that attract birds. This drought-tolerant shrub is hardy in USDA zones 7 to 9 and will grow in most kinds of soil, including fast-draining sandy soil. Either a partial shade or full sunlight exposure is fine. Thryallis is hardy in USDA zones 9 to 11, growing to a height and width of 6 feet with a curved contour and light green foliage. In late summer and fall, it produces bright yellow flowers held in 4- to 6-inch long clusters. It is a drought-resistant shrub that thrives in dry, fast-draining soil with a full sun exposure.
Year-round Floral Interest
Butterfly bushes (Buddleja davidii) and Knock Out roses (Rosa radrazz) are deciduous shrubs that bloom from spring through fall. In warm Mediterranean climates, however, they keep most of their foliage and continue to blossom, providing a year-round display. Butterfly bushes grow 6 and 12 feet tall and 4 to 15 feet wide, depending on the cultivar, with long, arching branches and gray-green foliage. They are hardy in USDA zones 5 to 10 and thrive in fast-draining soil that tends to remain dry. Knock Out roses are hardy in USDA zones 4 to 9, growing to a height of 4 feet and width of 3 feet. Their flowers may be single- or double-form and pink, red, yellow or white. Knock Out roses are drought-tolerant and highly resistant to blackspot and fungal diseases. Both shrubs will grow in partial or full sun exposures.