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The alder bonsai tree is a deciduous tree that grows in North America and Europe. It is a birch family member. It also grows widely in the United Kingdom and Ireland’s wetland forests, explaining the numerous stories and mysteries.

When completely grown, the conical-shaped tree reaches a height of around 90 feet. Usually, its bark is fissured and black. It is because Lichen prefers nesting in the bark cracks, particularly in humid circumstances. In comparison, twigs are frequently smooth and crimson. Young twigs are often sticky.

The alder tree’s leaves are immediately recognizable. They emerge from along the stem are purple or grey stems that extend a maximum length of around 4 inches. They are easily identifiable by their bright green color, Regardless of their size, they are not pointed. The leaf is shaped like a heart at the top and jagged edges on all sides.

The Alder begins to blossom from February until April of each year. The flowers are not dazzling since they are catkins without petals or fragrances. Both male and female catkins develop in a single tree. Male catkins are tall and thin and develop a bright yellow color when fully bloomed. Female catkins are typically oval, dense, and persistently green. Male catkins are usually solitary, whereas Female catkins are shown in bunches of three to eight blooms.

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Wind pollinates the female blooms, which mature into tiny cone-shaped fruits. The fruits develop in the winter and open to Free their seeds into the breeze in the spring. The alder tree’s fruits aren’t eaten. They are just seed-filled wooden cases.

Varieties of Alder Tree

Eight distinct species arise from Alder trees. The type you plant Relies on your place, the climate, and the space you have in your garden. Some of Alder’s most common species are:

  • Red Alder: Bark is the origin of garment coloration. It grows in the appropriate conditions to around 120 feet, and It needs maximum sunlight and has USDA hard zones from 5 and 9. The leaves’ edges curl within.
  • Black Alder: this kind accepts a slight shadow between 40 and 60 feet of height and has hardiness zones of the USDA between 3 and 7 feet. The bark is utilized in traditional medical treatment and wood for the production of cabinets and doors.
  • Seaside Alder: a frequent occurrence on the East Coast ranges from 12 to 20 feet in height. It is the perfect Alder for growing in the garden because there are not many areas needed. This one flowers in the fall, unlike other alders. It flourishes in direct sunlight. even if it tolerates partial shade.
  • Hazel Alder: It is a tiny, self-cloning tree that is not more than 20 feet. It has USDA hardiness areas between 5 and 9 and is essentially more of a tree than a shrub. It’s usually invasive.

How long does it take to grow Alnus (Alder) Bonsai?

Alder Bonsai trees are rapidly growing deciduous trees that thrive in USDA plant hardiness zones 6 to 10. Therefore, they are desired for both their hardwood and their early spring flower show. Although Alder comes in various varieties, only the red (Alnus rubra Bong.) and white (Alnus rhombifolia) species are native to California. When the trees are young, they are pruned to maintain their form. But after they reach 60 feet in height, only minor pruning is necessary to maintain the tree’s health and appearance.

Alder trees are wide leafy trees with floral clusters and brown woody cones called strobiles. Several Alder trees originated in North America and Europe, with the Red Alder and Black Alder being the most prevalent.

Alders are becoming towering shadow trees or large shrubs which thrive on damp, swampy soil. In the landscape, Alders are readily recognized by their solid circular crown, clenched green leaves, and brown coniferous cones. Alder cones grow from catkins (conical floral clusters) and stay on the tree throughout the winter, giving the naked branches a distinctive look.

In suburban landscapes, alder trees are extremely rare. Due to their size, wide canopy, and wetland inclination, they are not great trees for the landscape. On the other hand, some types of alder make excellent hedge shrubs for security and protection.

Alder (Alnus) is a species of deciduous flowering trees that are members of the Betulaceae family. There are around 35 alder species, which include both big trees and shrub-like trees. Numerous alder species reach a height of between 66 and 100 feet (20 – 30 meters). The majority of alder species flourish in USDA zones 5 through 8; however, certain species are more or less cold-hardy.

Alders are generally fast-growing trees with a lifespan of 60 to 70 years. Nevertheless, some alder trees may survive up to 100 years.

The alder species is known for its ability to grow in soggy, wet soils. Alders thrive near rivers, stream banks, swampy areas, and wetlands. This property makes alders a popular choice for reforesting areas with poor soil or drainage.

The arching, conical crown of an alder tree is made up of crooked, gnarled limbs. The arching branches are covered with glossy green pointed oval or rounded leaves, most of which have significant serration around the edges. Branches, like the trunk, are coated in a light grey to dark grey bark.

How to Plant and Grow Alnus (Alder) Bonsai?

Alder Bonsai trees are quite simple to grow and maintain. Although certain alder types grow more rapidly than others, they are long-lived trees that would take many years to attain their maximum thickness and height. Patience is required in this case. There are typically two methods for alder tree establishment. First, either from seed or a cutting, it may start. This guide explains how to correctly grow an alder tree.

  • The Alder seeds can collect from mature cone-shaped fruits. Annually, in May, matured the flat seeds.
  • Place the seeds in an airtight bag Add little damp wood chips and store them in the refrigerator for approximately three months
  • Fill a small container with soil and organic fertilizer when ready to plant the seeds, and put the seeds without covering on the surface.
  • Immediately water the soil and maintain soil moisture until the seeds grow.
  • After around three months, transplant the saplings into their permanent location in your garden.
  • Select a place in the garden where most direct sunshine all day.
  • Make a hole double the width and depth of the alder rootball.
  • Carefully remove the sapling and the dirt surrounding the rootball from the container and put it into the hole.
  • Fill the soil back and pack it to push the pockets out of the air.
  • Water the sapling to let the soil settle immediately.

The Alnus (Alder) Bonsai: How to Care for It

When an alder Bonsai tree establishes itself in the soil, it effectively self-maintains. Except for initial trimming and watering, the tree takes care of itself and requires little from you after that. That is the simplest method.


Whether you are a monster like the Red Alder or a handier Seaside Alder, you still have to prune their alder trees. It is important to form the trees and prevent them from being a branch and stem. Remove any crossing or tangling branches. In addition, trim one or two of the low branches each year until the tree matures. The best time to trim a tree in the autumn, when the leaves are falling. If you like to prune in spring, try to avoid a sap leak before the growth cycle starts. March is generally the optimum month for spring trimming.


Although the alder tree generates sufficient nitrogen in its roots, it still requires fertilizer in its early years. A properly balanced, granular, or fluid fertilizer gives the tree a healthy beginning and boosts its growth. Mix with water and then apply to the liquid fertilizer about three times a year between April and the end of July. Granular fertilizer should function in the soil at a rate of 2 pounds per 100 square feet of soil. Only apply once a year in April. You may also use and work organic compost on the soil in the same way. When the tree begins distributing nitrogen to the ground, it won’t fertilize again.

Parasites and diseases

Due to the high amount of nitrogen in the alder tree roots, it is less susceptible to disease than other members of the birch family. However, the babe still feeds on and makes an enormous hole in the leaves of the tree.

Furthermore, some diseases stand out and may pose a danger to the tree’s development, or possibly life itself.

  • Phytophthora: this disease destroys the leaves of the tree and the bark. The leaves may not belong, while white dots bark as they fall. It’s a terrible disease and the tree will perish.
  • Artist Bracket: a fungus disease that damages the roots, trunk, and branches of the trees. Apply a fungal herbicide to maintain the tree and remove the affected portions.