The shandong maple, a medium-sized maple tree native to northern China, is grown as an ornamental plant. It is extremely easy to grow and makes an excellent street or small landscape tree. It tends to mature swiftly and can be anticipated to live for 100 years if properly cared for.
I. Appearance and Characteristics
Acer truncatum, the Shantung maple, Shandong maple, or purpleblow maple, is a maple native to northern China, in the provinces of Gansu, Hebei, Henan, Jiangsu, Jilin, Liaoning, Inner Mongolia, Shaanxi, Shandong, Shanxi, and to Korea.
It is a medium-sized deciduous tree growing to 15 meters (49 ft) tall with a broad, rounded crown. The bark is smooth on young trees, becoming shallowly ridged with age. The leaves are opposite, palmately lobed with five lobes, 5 centimeters (2.0 in) to 12 centimeters (4.7 in) long and 7 centimeters (2.8 in) to 11 millimeters (0.43 in) broad, with a 3 centimeters (1.2 in) to 10 millimeters (0.39 in) petiole; the lobes are usually entire, but occasionally with a pair of teeth on the largest central lobe, and the margin is often wavy. The petiole bleeds a milky latex when broken.
The flowers are in corymbs, yellow-green with five petals 5 millimeters (0.20 in) to 7 millimeters (0.28 in) long; flowering occurs in early spring. The fruit is a double samara with two winged seeds, the seeds are disc-shaped, slightly flattened, 13 millimeters (0.51 in) to 18 millimeters (0.71 in) across. The wings are 2 centimeters (0.79 in) long, widely spread, approaching a 180° angle. The bark is greenish-gray, smooth in young trees, becoming shallowly grooved in maturity. It is drought and heat resistant.
It is closely related to, and often difficult to distinguish from, Acer amplum, Acer cappadocicum, and Acer pictum subsp. mono, which replaced it further south and west in China, and in Japan. From Acer cappadocicum it is best distinguished by the shoots which turn brown by their first winter, not remaining green for several years. From Acer mono (syn. A. pictum auct. non Thunb.) It is best distinguished by the larger, thicker (less flattened) seeds. Acer truncatum is very unusual among maples in showing hypogeal germination.
II. How to Grow and Care
Sunlight
Shandong maple thrives in conditions that offer full sun, which means it requires at least six hours of direct sunlight per day to reach its growth potential and maintain optimal health. However, shandong maple exhibits considerable light tolerance, adapting well to partial sun conditions, where it can still grow healthily with light shade during part of the day. This adaptability in light exposure allows for a range of outdoor planting locations, from open spaces that receive plentiful sunlight to areas with dappled shade. In non-optimal light, shandong maple may adjust its growth patterns and leaf coloration to maximize light absorption, ensuring resilience and sustained health even when light conditions are less than ideal.
Temperature
The shandong maple has good cold resistance and is able to tolerate low temperatures. The shandong maple is native to the margins of forests in China, Japan, and North Korea, so these trees generally prefer a humid environment. Most shandong maple plants have shallow root systems, so they should be watered frequently during the summer. For some varieties, a sprayed mist should be provided during the summer to increase the humidity of the air around them.
Watering
Shandong maple thrives in conditions that mimic its native woodland habitat, where it benefits from consistent moisture. This species exhibits a moderate tolerance to drought once established but prefers a stable environment with regular watering. Shandong maple should be watered once every two weeks to maintain optimal hydration. Cultivated primarily outdoors, shandong maple demonstrates notable resilience during its growing season, efficiently utilizing water to support its lush foliage.
Soil
The shandong maple does not have many specific requirements for soil. It is a forest native, so it prefers well-drained soil that is rich in humus and slightly acidic. Its main root will extend deep into the soil, but its tiny fibrous roots will be concentrated near the soil surface, so accumulated water in the soil tends to cause root rot.
Fertilizing
To optimize shandong maple’s growth, apply a balanced fertilizer (like 10-10-10) in spring as new growth appears. During its active growing season, shandong maple benefits from monthly fertilization with a higher nitrogen content to support lush foliage. Adjust to a quarter-strength during dormancy. Over-fertilizing can harm shandong maple, so follow recommended rates (1 tablespoon per square foot) and always water thoroughly after application to prevent root burn. Seasonal variations require a reduction in fertilization frequency and volume in fall and winter. Regular feeding enhances shandong maple’s vitality, aiding in robust branching and vibrant leaves.
Pruning
Pruning is mainly used to enhance internal ventilation, improve shoot formation, promote growth, and for shaping. The common approach to pruning is to remove any old or weak branches, remove any branches that disrupt the shape of the tree, and remove any branches that cross other branches. Pruning is used to control the plant according to the required height and shape. Generally, this follows the “Y-type” pruning method.
It is possible to prune a shandong maple throughout the year, but the coldest winter months should be avoided to prevent damage to the plant. Major pruning to shape a maple can be performed following defoliation in the fall, or prior to leaf growth in the spring. It is recommended to prune in the fall because withered and full buds can be easily distinguished.
According to the shaping plan, you can prune any withered buds and keep the full ones, thus making your tree healthier. For pruning in the summer, diseased, weak, or dead branches can be removed, mainly to enhance the tree’s ventilation.
If grown as a potted plant, the roots can easily occupy the entire flowerpot due to the limited space. This can make a shandong maple prone to aging if an old flowerpot is not changed. It is recommended that old roots are pruned during the dormancy period, that is, cut off any old, coarse, diseased, and weak roots.
Propagation
Shandong maple is effectively propagated by sowing its seeds. To encourage successful germination, it’s essential to start with fresh, high-quality seeds. Treatment for overcoming dormancy and achieving uniform growth can be beneficial. Sow the seeds shallowly in a well-draining substrate. Consistently moist conditions and stable temperatures aid in optimal germination. After sprouts emerge, provide ample light and protect seedlings from extreme elements to ensure vigorous growth.
Transplanting
Shandong maple thrives best when transplanted during the S1-S3 time frame, a period that offers the perfect balance of weather conditions, promoting faster root establishment. Location-wise, a sunny spot with partial shade and well-drained soil suits it best. When transplanting, remember to handle the plant gently to avoid damaging the roots.
Pests and Diseases
The trees can attract aphids, so keep your eye out for these small, sap-sucking bugs. Often, you can wash them from leaves and stems with the hose or spray them with soapy water. The trees can be susceptible to root rot and verticillium as well, but they are resistant to leaf scorch.