| General Description | Japanese Aspen is a deciduous, large tree that is fast growing. It contains both male or female catkins and is pollinated by wind. The leaves are thin and round, usually green in colour turning yellow in autumn. |
| ID Characteristic | The leaves are green and glossy in colouration with a silver underside. They are also cordate with serrate edges. The terminal buds are wide and rounded, ending in a point, and the auxiliary buds are arranged in an alternate pattern. The bark is dark brown, cracked, and rough at its base while smooth and lighter in colouration higher into the tree. Japanese Aspen contains long, green catkins that turn white in colour in autumn. |
| Shape | Tall, slim tree with round green leaves ending in a point, somewhat pyramidal. Leaves will become glossy as they mature and will change into a yellow colour during autumn. |
| Landscape | Although seen as a specimen tree, there are not many uses for Japanese Aspen in terms of landscaping. This is possibly due to the tree’s aggressive root system, which may damage nearby structures if planted to close to them. However, parts of this tree are known to be edible, as the leaves and shoots can be cooked and consumed. They have also proven to be useful as windbreaks because of the tree’s rapid growth. |
| Propagation | Seeds of Japanese Aspen will ripen in spring and must be planted within a few days of this time, as they have a very short window of viability. The seed must be collected in wild areas where no other Poplars are growing. This is because Japanese Aspens hybridize frequently with others in its genus and can prevent the seeds collected from coming true. The seeds require light to germinate and so they must be surface planted. This means that the seed is gently pressed into a tray filled with soil and covered with clear glass or plastic to keep the area moist and warm. Once the seeds have outgrown the tray, they must be transferred into individual pots to continue growing. By this time, the clear glass or plastic is no longer needed to assist the seed in growing. If adequate growth has been achieved, the seeds may then be planted outside in the late summer. If the seeds have not achieved sufficient enough growth for them to be moved outside into their permanent locations, they may be kept inside until late spring. Stem cuttings of the tree may also be propagated. They should be taken from mature wood and be around 20-40 cm in length. Plant in the months of November to December in a sheltered outdoor area. It will begin to sucker in early spring. |
| Cultivation | Grown best in full sun and cold, moist soil. It is tolerant of other soil conditions with an exception to overwatered soil and should not be planted in shaded areas. Performs best in alkaline soils. Can be grown in a variety of soil types such as clay or sand. Although resistant to drought and colder weather, it is not advised to be planted in urban areas due to its ability to damage underground pipes or other nearby structures. |
| Pests | Common pests of Japanese Aspen include leaf beetles and sawflies; however, they are not known to severely harm the tree. It may also be susceptible to various diseases, such as leaf spots or tree rusts. More serious diseases this tree may encounter are bacterial canker or honey fungus. |
| Notable Specimens | A grafted Japanese Aspen was documented at the National Botanic Gardens in Glasnevin, Ireland. However, it struggled to grow and only achieved a height of around 4 m. |
| Habitat | Japanese Aspen prefers moist soil and cold temperatures. It can be found naturally in the mountainous regions of Japan, in areas with full sun. |
| Bark/Stem Description | Bark is dark brown in colouration with younger parts of the tree being light brown to white further up. Older parts of the tree are covered in long, distinct lenticels. The bark is also soft, yet resistant to abrasions. |
| Flower/Leaf Bud Description | Terminal buds are wide and pointed and can be up to 2 cm in length. Buds are also covered in small hairs and are smooth. They are dark brown, almost black in colouration. The auxiliary buds are arranged in an alternate pattern. |
| Leaf Description | The leaves are cordate in shape, with serrate sides. They are measured to be around 7 cm long and 2 cm wide. They are thin and glabrous in texture. Entire leaf margins and net-veined leaves. Colours range from dark green in the summer to yellow in autumn. |
| Flower Description | Flowers come in the form of catkins, which are long, fragile flower clusters and are pollinated by wind, about 3 cm. They can be either male or female. They are usually green in colour but change to white in autumn as they begin to fall from the tree. Japanese Aspen has a flowering period between May and June. |
| Fruit Description | The fruit comes in cylindrical, white clusters that can be either male or female. They are roughly 3 cm in length when fully grown. They materialize in late winter and continue to grow into spring. |
| Colour Description | The leaves are a glossy green colour and will turn yellow in autumn. The flowers and bloom are also green but will turn white in autumn. The bark ranges from dark brown on older parts of the tree to a light brownish-white colour on younger parts of the tree. |
| Texture Description | Fine textured plant throughout the seasons. |