Alderleaf Buckthorn
Alderleaf Buckthorn (Rhamnus alnifolia) is a medium-sized native shrub common to moist, shaded forests of the Pacific Northwest. It grows from 3-10 feet tall and 5 feet wide with slippery branches and pinnately compound leaves that are dark-green and glossy. Older plants develop a beautiful reddish-brown bark that is harvestable after the plant is 12-15 years old. Alderleaf Buckthorn also produces small yellow-green flowers in the spring followed by small black fruits in the fall.
Alderleaf Buckthorn appreciates consistently moist soil and should be watered when the top inch or two of soil is dry. Slow and deep watering should be used to keep the roots well hydrated. Overwatering should be avoided to prevent root rot.
Alderleaf Buckthorn prefers partial to full shade and cannot tolerate direct sunlight or heat. It does best in shaded areas with bright indirect light. It will not tolerate drought conditions, so it’s important to keep the soil consistently moist when growing this plant in a home or garden.
Alderleaf Buckthorn prefers cool climates with mild to moderate temperatures between 45-80 degrees Fahrenheit (7-27 degrees Celsius). The plant will not survive severe cold temperatures below 10 degrees Fahrenheit (-12 degrees Celsius) and it also cannot tolerate high heat.
Alderleaf Buckthorn enjoys high humidity levels and should be misted or placed in a room or container with a humidifier to help reduce dryness.
Alderleaf Buckthorn prefers an evenly moist, fertile soil with a pH of 6.0-7.5. To ensure good drainage and adequate water flow, a well draining potting soil should be used. Additionally, a layer of mulch can be spread around the plant to help retain water and regulate temperature.
Alderleaf Buckthorn should be fertilized once a year in early spring with a balanced fertilizer such as 10-10-10. If the leaves start to yellow or the plant is not growing well, fertilizer can be applied again in the summer. When applying fertilizer, it should be spread evenly over the soil and watered thoroughly.
Insects such as aphids, mealybugs, scales, and spider mites can sometimes be a problem for Alderleaf Buckthorn, depending on the humidity and location. Spider mites prefer hot, dry environments so frequent misting and cooler temperatures should be used to discourage them. Mechanical removal or insecticidal soap may be used if necessary. Most common garden pests such as slugs and snails rarely affect this plant.
Alderleaf Buckthorn should be repotted every two to three years, or when the pot is too small to support the growth of the bush. When selecting a new pot, be sure to select one that is at least twice the current size. A potting soil with good drainage should be used to allow adequate water flow and prevent waterlogging of the roots.
Alderleaf Buckthorn requires minimal pruning. Yearly pruning should take place to remove any dead, diseased, or unwanted branches in early spring or late winter. When pruning, be sure to use caution and only prune the dead wood, avoiding any healthy branches or stems.
Mulching around the Alderleaf Buckthorn is very beneficial for water retention and temperature regulation. A thick layer of mulch should be spread around the plant extending 2-3 inches out from the trunk. Organic mulches such as wood chips or shredded bark are best.
Alderleaf Buckthorn can easily be propagated in late fall or early winter using hardwood cuttings. Cuttings should be taken from the tips of healthy branches and planted directly into soil or a prepared rooting medium. The soil or rooting medium should be kept moist but not overly wet to encourage root growth. After 8-12 weeks, the cuttings should have rooted and be ready to be transplanted.
Alderleaf Buckthorn is best suited to sheltered areas and should be staked or provided with some form of wind protection for optimum growth. This will reduce the need for pruning and help to maintain an attractive appearance.
Alderleaf Buckthorn doesn’t require a distinct rest period, however it should not be fertilized for a couple of months over the winter to simulate a natural winter dormancy.
Alderleaf Buckthorn is not toxic to pets.