The African Sumac (Rhus lancea or Searsia lancea) is a popular evergreen tree, especially in arid and semi-arid regions of its native southern Africa. Known also as Karee or Willow Rhus, its appeal comes from graceful, weeping foliage, a dense canopy, and remarkable drought tolerance once established. This makes it a low-maintenance option that provides consistent shade year-round, well-suited for hot climates, making it a functional and attractive landscape choice.
Choosing the Right Spot and Planting
African Sumac thrives in full sun, receiving over six hours of direct sunlight daily, though it tolerates partial shade. Too much shade can lead to reduced vigor and leggy growth. This tree adapts to various soil types, including poor soils, but requires well-draining conditions to prevent root rot.
When planting, prepare a hole twice the width of the root ball and deep enough so the top sits slightly above the soil surface, about two inches. Amend heavy or compacted soil with coarse sand or perlite to improve drainage. After placing the tree, backfill the hole with soil, ensuring no air pockets. Water the newly planted tree slowly and thoroughly to the depth it was planted.
Routine Care Practices
Once established, African Sumac exhibits significant drought tolerance. During its first few years, regular watering is necessary to develop a strong root system. After establishment, deep, infrequent watering is recommended, allowing the soil to dry out between applications to prevent overwatering and root rot. Mature trees may need watering every 1-2 weeks, depending on climate, with less water in cooler months.
Established African Sumac trees generally do not require regular fertilization. If the tree is in poor soil or shows stunted growth, apply a balanced slow-release fertilizer once a year in spring. The tree tolerates a wide range of soil pH, from neutral to moderately alkaline, typically between 6.5 and 8.0. Avoid over-fertilization, which can harm the tree.
Pruning Your African Sumac
Pruning African Sumac helps maintain its shape, promotes healthy growth, and removes undesirable branches. The best time for pruning is late winter to early spring, before new growth emerges. Remove dead, diseased, or damaged branches. Thinning dense areas within the canopy also enhances air circulation and light penetration, which can help reduce pest problems.
For shaping, remove lateral limbs that grow too low to create more open space beneath the canopy. Make clean, precise cuts just outside the branch collar to facilitate proper healing. While the tree can tolerate heavy pruning, avoid removing more than 25 percent of its foliage in a single season to minimize stress. This approach encourages a robust structure.
Addressing Common Issues
African Sumac is generally hardy and resistant to significant pest and disease problems, though some issues can arise from environmental conditions. Root rot is common in poorly drained or overwatered soils, causing wilting and leaf drop. Proper drainage and allowing soil to dry between waterings are crucial for prevention.
Pests like aphids and scale insects can sometimes affect African Sumac, but infestations are usually minimal. Aphids can be controlled by blasting them off with water or using insecticidal soap for heavier infestations. Yellowing or drooping leaves may indicate insufficient or excessive watering. Leggy growth suggests too little sun, while leaf burning can indicate too much sun.
Managing Growth and Roots
African Sumac typically grows to a moderate size, reaching 20 to 30 feet tall with a similar spread, and has a moderate growth rate of about 24 inches per year. Its root system is generally non-aggressive, making it suitable for urban landscapes and near structures. However, caution is advised near foundations or paved areas for very mature trees due to their extensive water-absorbing roots.
African Sumac can self-seed readily in certain climates, producing berry-like fruits with seeds that germinate easily, especially with a seasonal water source. It can also produce suckers from its roots. Regular monitoring for seedlings and suckers helps manage its growth and spread within the landscape.