Japanese Pagoda Tree (Styphnolobium japonicum)

Japanese Pagoda Tree (Styphnolobium japonicum, formerly Sophora japonica), also commonly known as the Chinese Scholar Tree or Pagoda Tree, is a stunning deciduous tree prized for its elegant form and late-summer blooms. This landscape gem offers shade, beautiful flowers, and interesting seed pods, adding year-round visual appeal.

This article will delve into everything you need to know about the Styphnolobium japonicum, from its identification and care to propagation and potential problems. We’ll explore its beautiful Japanese pagoda tree leaves, pagoda tree flower, and pagoda tree fruit. We will also discuss if the Japanese pagoda tree invasive, the Japanese pagoda tree lifespan, and explore detail about the Japanese pagoda tree bark. Continue reading to unlock the secrets to successfully growing and enjoying this magnificent tree. Whether you’re looking to buy a Japanese Pagoda Tree or simply want to learn more, this guide is your one-stop resource.

1. Understanding the Japanese Pagoda Tree: Botany, History, and Uses

The Japanese Pagoda Tree, despite its name, is native to China and Korea. It was introduced to Japan centuries ago, where it became widely cultivated and gained its common name. The tree’s scientific name, Styphnolobium japonicum, reflects its botanical classification, while the older name, Sophora japonica, is still frequently encountered.

Common name	Japanese Pagoda Tree, Chinese Scholar Tree, Pagoda Tree
Botanical name	Styphnolobium japonicum (formerly Sophora japonica)
Family	Fabaceae (Leguminosae)
Genus	Styphnolobium
Species	japonicum
Origin	China, Korea
Native	Not native to USA, but widely naturalized in some areas.
Life cycle	Perennial
Plant type	Deciduous Tree
Hardiness zone	4, 5, 6, 7
Sunlight	Full Sun (tolerates Partial Shade, but flowering may be reduced)
Maintenance	Low to Moderate
Water	Moderate (Drought-tolerant once established)
Drainage	Well-Drained
Spacing	30-50 ft. (depending on cultivar and desired growth)
Flowering period	Late Summer (July-August)
Height	50-75 ft. (some cultivars may be smaller or larger)
Growth rate	Moderate (1-2 ft. per year; some cultivars like ‘Regent’ are faster)
Flower color	Creamy White, Pale Yellow
Stem color	Young stems are green, maturing to gray-brown.
Flower benefit	Attracts Pollinators (bees, butterflies), Fragrant, Showy Late-Summer Blooms
Garden style	Urban, Shade Garden, Park, Large Landscape
Uses	Shade Tree, Ornamental Tree, Specimen Plant, Street Tree (in suitable locations)
Soil pH	Adaptable, prefers slightly acidic to neutral (6.0-7.0)
Propagation	Seed, Cuttings
Leaf type	Pinnately Compound
Leaf color	Dark Green, turning yellow in fall (fall color often not showy)
Fruit type	Indehiscent Pod (beaded appearance)
Bark	Smooth and green when young, becoming gray-brown and fissured with age.
Disease resistance	Generally good, but susceptible to some pests and diseases, particularly when stressed. ‘Regent’ cultivar has improved disease resistance.
Toxicity	Mildly toxic if large quantities of seeds/pods are ingested.
Invasive Potential	Low in most of the US; can self-seed. Considered invasive in parts of South Africa.
Lifespan	Long-lived (100+ years under optimal conditions).

This tree belongs to the Fabaceae (or Leguminosae) family, the legume family, which also includes beans, peas, and clover. This family connection is evident in the tree’s pea-like flowers and seed pods.

1.1 Botanical Description and Identification

The Japanese Pagoda Tree is a medium to large-sized deciduous tree, typically reaching heights of 50 to 75 feet (15-23 meters) with a similar spread. However, some specimens can grow even larger under optimal conditions. The tree has a rounded or vase-shaped crown, creating a graceful silhouette.

• Leaves: The leaves are pinnately compound, meaning they are composed of multiple leaflets arranged along a central stem (rachis). Each leaf typically has 7 to 17 leaflets, which are ovate to lanceolate in shape, 1 to 2.5 inches (2.5-6 cm) long, and dark green in color. The leaves emerge late in spring and turn yellow in the fall, although the fall color is often not particularly showy.
• Flowers: The flowers are the tree’s most striking feature. They are creamy white or pale yellow, pea-like in shape, and borne in large, showy panicles (branched clusters) that can be 8 to 12 inches (20-30 cm) long. The flowers typically bloom in late summer (July-August), providing a valuable source of nectar for bees and other pollinators when few other trees are in bloom. They also have a very pleasant fragrance.
• Fruit: The fruit is a slender, indehiscent (doesn’t split open) pod, 2 to 4 inches (5-10 cm) long, that is constricted between the seeds, giving it a beaded appearance. The pods are initially green, maturing to brown, and often persist on the tree through the winter.
• Bark: The bark of young trees is smooth and green. As the tree matures, the bark becomes gray-brown and develops shallow fissures and ridges, providing textural interest.
• Form: The Japanese Pagoda Tree’s branching pattern is often irregular, creating a picturesque, almost sculptural quality.

1.2 Historical and Cultural Significance

The Japanese Pagoda Tree has a long and rich history, particularly in East Asia. In China, it was traditionally planted near Buddhist temples and scholar’s gardens, hence the common name “Chinese Scholar Tree.” The tree was believed to ward off evil spirits and bring good luck. The wood was also used for carving and construction.

In Japan, the tree became associated with learning and scholarship, often planted near schools and libraries. Its elegant form and late-summer blooms made it a popular choice for ornamental planting.

1.3 Uses of the Japanese Pagoda Tree

Beyond its ornamental value, the Japanese Pagoda Tree has several practical uses:

• Landscape Tree: It’s an excellent shade tree for parks, large gardens, and streets. Its tolerance of urban conditions makes it suitable for city planting.
• Medicinal Uses: Various parts of the tree, particularly the flower buds and pods, have been used in traditional Chinese medicine for centuries. Compounds extracted from the tree are believed to have anti-inflammatory, antioxidant, and hemostatic (stops bleeding) properties. Note: Always consult with a healthcare professional before using any plant for medicinal purposes. One particular compound, Troxerutin, is used to manufacture medicines aimed at protecting blood vessels.
• Dye Source: The flower buds can be used to produce a yellow dye for textiles.
• Honey Production: The flowers are a significant source of nectar for honeybees, producing a high-quality honey.
• Wood: While not as commercially important as some other hardwoods, the wood of the Japanese Pagoda Tree is strong and durable, and can be used for furniture, carving, and other woodworking projects.

2. Growing and Caring for Your Japanese Pagoda Tree

The Japanese Pagoda Tree is relatively easy to grow and care for, making it a good choice for both experienced and novice gardeners. However, like all trees, it has specific needs that must be met to ensure its health and longevity.

2.1 Choosing the Right Location

• Sunlight: The Japanese Pagoda Tree thrives in full sun, requiring at least six hours of direct sunlight per day. While it can tolerate partial shade, flowering will be reduced, and the tree may become leggy.
• Soil: The tree is adaptable to a wide range of soil types, including clay, loam, and sand. However, it prefers well-drained soil that is slightly acidic to neutral (pH 6.0-7.0). It does not tolerate poorly drained or waterlogged soils. A soil test is recommended before planting to be sure of the soil’s characteristics.
• Space: Consider the tree’s mature size when selecting a planting location. Allow ample space for it to reach its full height and spread without crowding other plants or structures. Avoid planting it too close to buildings, power lines, or sidewalks.
• Climate: The Japanese Pagoda Tree is hardy in USDA zones 4 through 7. It can tolerate both heat and cold, but it may be damaged by late spring frosts, which can kill new growth.

2.2 Planting Your Japanese Pagoda Tree

• Timing: The best time to plant a Japanese Pagoda Tree is in the spring or fall, when the weather is cool and the soil is moist. Avoid planting during hot, dry periods.
• Procedure:
  1. Dig a hole that is twice as wide as the root ball and just as deep.
  2. Carefully remove the tree from its container, gently loosening any circling roots.
  3. Place the tree in the hole, ensuring that the top of the root ball is level with the surrounding ground.
  4. Backfill the hole with soil, tamping it down gently to remove air pockets.
  5. Water the tree thoroughly after planting.
  6. Apply a 2-3 inch (5-7.5 cm) layer of mulch around the base of the tree, keeping it away from the trunk to prevent rot.

2.3 Watering and Fertilizing

• Watering: Newly planted trees need regular watering, especially during the first year, to establish a strong root system. Water deeply and thoroughly whenever the soil feels dry to the touch. Established trees are relatively drought-tolerant, but they will benefit from supplemental watering during prolonged dry periods.
• Fertilizing: The Japanese Pagoda Tree is not a heavy feeder, and excessive fertilization can lead to weak growth and reduced flowering. In most cases, a single application of a balanced, slow-release fertilizer in early spring is sufficient. If your soil is poor, you may need to fertilize more frequently. Follow the instructions on the fertilizer package carefully.

2.4 Pruning and Training

• Pruning: The Japanese Pagoda Tree requires minimal pruning. The best time to prune is in late winter or early spring, before new growth begins. Remove any dead, damaged, or crossing branches. You can also prune to shape the tree or to maintain its size. Avoid heavy pruning, as this can stimulate excessive growth and weaken the tree.
• Training: Young trees may need to be trained to develop a strong central leader and a well-balanced branch structure. This can be done by selectively pruning branches and using stakes to support the tree if necessary.

2.5 Propagation

The Japanese Pagoda Tree can be propagated from seed or by cuttings.

• Seed Propagation:
  1. Collect seeds from ripe pods in the fall.
  2. Scarify the seeds by nicking or filing the seed coat to allow water to penetrate. This can be achieved by rubbing the seeds between two sheets of sandpaper.
  3. Soak the seeds in water for 24 hours.
  4. Sow the seeds in a well-drained seed-starting mix in the spring.
  5. Keep the soil moist and warm (around 70°F/21°C).
  6. Germination typically occurs within 2-4 weeks.
  7. Transplant the seedlings to individual pots once they have developed a few sets of leaves.
  8. Grow the seedlings in a protected location for the first year before planting them outdoors.
• Cutting Propagation:
  1. Take softwood cuttings (from new growth) in the late spring or early summer.
  2. Cuttings should be 4-6 inches long and have several leaves.
  3. Remove the lower leaves and dip the cut end in rooting hormone.
  4. Insert the cuttings into a well-drained rooting medium, such as perlite or a mixture of peat moss and sand.
  5. Keep the cuttings moist and humid, and provide bottom heat if possible.
  6. Roots should develop within 4-8 weeks.
  7. Transplant the rooted cuttings to individual pots and grow them in a protected location until they are ready to be planted outdoors.

3. Troubleshooting Common Problems: Pests, Diseases, and Other Issues

While generally a hardy tree, the Japanese Pagoda Tree can occasionally be affected by pests, diseases, and other problems. Early detection and treatment are crucial for minimizing damage.

3.1 Pests

• Leafhoppers: These small, sap-sucking insects can cause leaf stippling and distortion. They can also transmit diseases. Control leafhoppers with insecticidal soap or horticultural oil.
• Japanese Beetles: These beetles can skeletonize leaves, causing significant damage. Handpick beetles or use traps to control them. Insecticides can also be used, but be aware that they can also harm beneficial insects.
• Aphids: These tiny, soft-bodied insects suck sap from leaves and stems, causing distortion and yellowing. They can also transmit diseases. Control aphids with insecticidal soap or horticultural oil. A strong blast of water from a hose can also dislodge them.
• Scale Insects: These small, immobile insects attach themselves to branches and leaves, sucking sap and causing weakening. Control scale insects with horticultural oil or systemic insecticides.
• Borers: Several species of borers may attack stressed Japanese Pagoda Trees. These larvae tunnel under the bark, disrupting the flow of water and nutrients. Prevent borer infestations by keeping the tree healthy and avoiding injury. Prune out infested branches and destroy them.

3.2 Diseases

• Canker Diseases: Several fungal pathogens can cause cankers, which are sunken, dead areas on branches or the trunk. Cankers can girdle branches, causing dieback. Prune out infected branches, making cuts well below the cankered area. Avoid wounding the tree, as wounds can provide entry points for pathogens.
• Leaf Spot Diseases: Several fungal pathogens can cause leaf spots, which are small, discolored areas on leaves. Leaf spot diseases are usually not serious, but they can be unsightly. Rake up and destroy fallen leaves to reduce the spread of disease. Fungicides can be used in severe cases.
• Powdery Mildew: This fungal disease appears as a white, powdery coating on leaves. It is most common in humid conditions. Improve air circulation around the tree and avoid overhead watering. Fungicides can be used if necessary.
• Verticillium Wilt: This soilborne fungal disease can cause wilting, yellowing, and dieback of branches. There is no cure for Verticillium wilt. Prevent the disease by planting in well-drained soil and avoiding overwatering.

3.3 Other Issues

• Chlorosis: Yellowing of leaves between the veins, often caused by iron deficiency. This is most common in alkaline soils. Amend the soil with iron chelate or sulfur to lower the pH.
• Frost Damage New growth can be sensitive to late spring frosts. If frost damage occurs, wait to prune out the dead parts of the tree until after any danger of further frosts has passed.
• Poor Flowering: This can be caused by several factors, including insufficient sunlight, excessive fertilization, or improper pruning.

4. Where to Buy a Japanese Pagoda Tree: Finding Reputable Sources

Finding a healthy Japanese Pagoda Tree from a reliable source is crucial for its long-term success. Here are some options to consider:

4.1 Local Nurseries and Garden Centers

• Advantages: Visiting a local nursery allows you to inspect the trees in person, choosing one with a healthy appearance and good structure. You can also get advice from knowledgeable staff. Nurseries often offer larger, more established trees.
• Disadvantages: Local nurseries may have a limited selection, and prices may be higher than online retailers.

4.2 Online Retailers

• Advantages: Online retailers often offer a wider selection of sizes and cultivars, and prices may be more competitive. Many online nurseries provide detailed information about the trees they sell.
• Disadvantages: You cannot inspect the tree in person before purchasing it. Shipping can be expensive, and there is a risk of the tree being damaged during transit. It’s crucial to choose a reputable online retailer with a good track record. Look for reviews and guarantees.

4.3 Finding Reputable Nurseries: Key Considerations

Whether you choose a local nursery or an online retailer, consider the following factors:

• Reputation: Look for nurseries with positive reviews and a good reputation for selling healthy plants.
• Selection: Choose a nursery that offers a variety of sizes and cultivars of Japanese Pagoda Trees, so you can find one that meets your specific needs.
• Plant Health: Inspect the trees carefully for signs of pests, diseases, or damage. Look for healthy foliage, a strong trunk, and a well-developed root system. Avoid trees with wilted leaves, broken branches, or signs of stress.
• Guarantees: Choose a nursery that offers a guarantee on its trees, so you can be confident that you are purchasing a healthy plant.
• Shipping Practices (for online retailers): Ensure the retailer uses appropriate packaging and shipping methods to protect the tree during transit.
• Customer Service: Look for a nursery with responsive and helpful customer service, in case you have any questions or problems.

Gardencenterpoint.com can help you connect with reputable nurseries in your area or online retailers that specialize in Japanese Pagoda Trees. We are dedicated to providing unbiased information to help you make the best purchasing decisions. We do not sell trees ourselves, but we provide a directory and resources to assist you.

5. Cultivars and Varieties of Japanese Pagoda Tree

While the species Styphnolobium japonicum is beautiful in its own right, several cultivars have been developed with specific characteristics, offering variations in size, form, and flowering.

5.1 ‘Pendula’ (Weeping Japanese Pagoda Tree)

This is a popular cultivar with gracefully weeping branches, creating a dramatic, cascading effect. It typically grows to a smaller size than the species, reaching heights of 15-25 feet (4.5-7.5 meters). ‘Pendula’ is an excellent choice for smaller gardens or as a focal point in a landscape.

5.2 ‘Regent’

This cultivar is known for its faster growth rate, more upright habit, and improved disease resistance. It typically reaches heights of 40-50 feet (12-15 meters). ‘Regent’ is a good choice for those who want a fast-growing shade tree. It is known to flower at a young age.

5.3 ‘Princeton Upright’

A more columnar form of the Japanese Pagoda tree, this cultivar grows to 60 feet tall, but with a spread of only 20-30 feet.

5.4 Others

Many other cultivars exist, but are less commonly sold, such as Columnaris, Variegata, and Fastigiata. When purchasing a tree, be sure of what cultivar it is, and that you are happy with its mature shape.

6. Frequently Asked Questions (FAQs) about Japanese Pagoda Tree

Q: Is the Japanese Pagoda Tree poisonous?

A: While some parts of the tree, particularly the seeds and pods, contain compounds that can be toxic if ingested in large quantities, the tree is not considered highly poisonous. However, it’s always best to keep children and pets away from any plant that is not specifically known to be edible.

Q: Is the Japanese Pagoda Tree invasive?

A: The Japanese Pagoda Tree is not considered a highly invasive species in most areas of the United States. However, it can self-seed, and seedlings may appear in unwanted locations. To prevent unwanted spread, remove seedlings as they appear. It is considered invasive in certain parts of South Africa.

Q: How long does a Japanese Pagoda Tree live?

A: Japanese Pagoda Trees can be long-lived, with a lifespan of 100 years or more under optimal conditions. However, their lifespan can be shortened by factors such as disease, pests, or poor growing conditions.

Q: When does the Japanese Pagoda Tree bloom?

A: The Japanese Pagoda Tree typically blooms in late summer (July-August), providing a valuable source of nectar for pollinators when few other trees are in bloom.

Q: How fast does a Japanese Pagoda Tree grow?

A: The growth rate of a Japanese Pagoda Tree depends on the cultivar and growing conditions. The species typically grows at a moderate rate, adding 1-2 feet (30-60 cm) of growth per year. Some cultivars, such as ‘Regent’, are known for their faster growth rate.

Q: Can I grow a Japanese Pagoda Tree in a container?

A: While Japanese Pagoda Trees are best suited for planting in the ground, young trees can be grown in large containers for a few years. Choose a container that is at least 24 inches (60 cm) in diameter and has good drainage. Use a high-quality potting mix and water regularly. Keep in mind that container-grown trees will need to be repotted periodically as they grow, and will eventually need to be planted in the ground to reach their full potential.

Q: Does the Japanese Pagoda Tree have aggressive roots?

A: The Japanese Pagoda Tree does not have a particularly aggressive root system compared to some other tree species. However, like all trees, its roots can spread widely, and they can potentially damage sidewalks, driveways, or underground utilities if planted too close.