Alder Bonsai Care [Betulaceae]

The Alder bonsai tree may not be as popular as other bonsai tree varieties, but it is still something worth considering adding to your collection. Discover everything there is to know about the is alder bonsai, how to care for it, and more.

Average Height40.00 to 60.00 feet
Average Spread20.00 to 40.00 feet
Origin CountryEurope, Western Asia, Northern Africa
Flower Bloom TimeMarch
WaterMedium to Wet
SunlightFull Sun to Part Shade

Can we bonsai Alder tree?

Yes, you can bonsai the alder tree.

The alder bonsai tree is a type of deciduous tree that thrives in Europe and North America. This is a member of the birch family ( we also recommend you learn what is Birch Bonsai ) and grows widely in the UK and the wetland forests of Ireland, which explains the numerous mysteries and stories around it.

Once completely grown, this conical-shaped tree can reach a full height of up to 90 feet. Its bark is often black and fissured. It is because lichen loves to nest in the bark cracks, especially in humid situations. Twigs are often crimson and smooth, with young twigs usually sticky.

Alder Bonsai June 2018

The leaves of the alder tree can be recognized right away. These emerge from along grey or purple stems extending a maximum length of up to 4 inches. You can identify them by their bright green color. The leaves are also not pointed whatever their size might be. The leaves are also heart-shaped on top with jagged edges on all the sides.

Alter trees start blossoming from February to April every year. These trees don’t have dazzling flowers because they are catkins with no fragrances or petals. Female and male catkins alike develop in one tree.

The male catkins are thin and tall and form a bright yellow hue when fully bloomed. Meanwhile, female catkins are often persistently green, dense, and oval. Male catkins are typically shown in bunches of 3 to 8 blooms.

The female blooms are pollinated by wind and these mature into small cone-shaped fruits. These fruits develop during winter, open to free the seeds in the spring breeze. The fruits of the alder tree are not eaten. These are only wooden cases filled with seeds.

Alder bonsai history

The oldest fossil pollen identified as alder comes from northern Bohemia that dates as far back as the late Paleocene era approximately 58 years ago.

Alder bonsai tree scientific name

The scientific name of the alder bonsai tree is Alnus glutinosa and belongs to the Betulaceae family. Some of its common names include common alder, European alder, black alder, or simply alder.

What does an Alder bonsai tree symbolize?

Swampy and wet, alder woods were believed to exude a mysterious atmosphere. The flowers have green dye that was used to camouflage and color the clothes of the outlaws such as Robin Hood and were also assumed to color the clothes of fairies.

The pale wood when cut turns a deep orange that gives the impression of bleeding. This is the reason why a lot of people feared the alder trees, with the Irish even believing that passing one during a journey is unlucky.

Alder bonsai indoor or outdoor?

The alder bonsai is best grown outdoors. This is because alder grows well on wetlands and along rivers. The tree also thrives anywhere as long as the ground is damp. The alder’s roots usually help stabilize riverbanks and stop the soil from getting washed away.

Alder bonsai care

Caring for your alder bonsai is easy as long as you remember a few important tips.

Alder bonsai temperature

There is no definite information regarding the suitable temperature for growing alder bonsai trees. The good news is that once the alder bonsai has established itself in the soil, this can already effectively self-maintain. Aside from the initial watering and trimming, the tree can take care of itself and needs very little help from you afterward.

Alder bonsai tree fertilizer

Even though the alder tree can generate enough amount of nitrogen in the roots, this still needs fertilizer during its early years. A fluid, granular, or properly balanced fertilizer can give your alder bonsai a healthy start and boost its growth.

Mix the fertilizer with water and apply it thrice a year between April to the later part of July. The granular fertilizer can work in the soil. Just apply this once a year. Organic compost can also be used and worked on the soil similarly. The tree will no longer fertilize again once the tree starts to distribute nitrogen to the ground.

Alder bonsai pruning/trimming

It is important to form your alder bonsai tree and stop it from being a stem and a branch. Get rid of any tangling or crossing branches. You also need to trim one low branch or two every year until your tree matures. Autumn is the ideal time for trimming a tree once the leaves start to fall. If you plan to prune your tree in spring, avoid a sap leak if possible before the beginning of the growth cycle. In general, March is the best month to trim in spring.

Alder bonsai repotting

The most ideal time for repotting your alder bonsai is during early spring when the tree is still dormant and its buds start to swell. The trees don’t sustain full-grown foliage during this stage that helps minimize the damaging effects of repotting.

Repotting during early spring also assures you that any damage incurred by the root system can be repaired right away once the tree begins to grow. Never repot your alder bonsai in winter or summer.

Alder bonsai pests and diseases

Due to the nitrogen’s high amount present in the roots of alder trees, these are less prone to diseases compared to other birch family members. However, some pests may continue to feed on and form large holes in the tree’s leaves.

Other diseases stand out and might pose some risks to the development or the life of the tree itself.

  • Artist bracket

This is a type of fungus disease that can damage the branches, trunk, and roots of the trees. Fungal herbicide can be applied for maintaining the tree and removing the affected spots.

  • Phytophthora

It is a disease that destroys the bark and leaves of alder trees. This is a terrible disease that might cause the tree to perish.

Alder bonsai soil

Alder bonsai is best grown in wet to medium soils in part shade to full sun. However, it can also tolerate a wide variety of soils, including infertile and dry ones. This also performs well in cool climates.

The alder species is popular for its ability to grow and thrive in wet and soggy soils. These trees can often be seen near wetlands, swampy areas, streambanks, and rivers. This property is the reason why alders are a common option for reforestation of areas with poor drainage or soil.

Alder bonsai watering

As a swamp-dweller, the alder bonsai is a certified water-lover. This tough tree’s wood doesn’t rot even if waterlogged, and instead, it turns harder and stronger.

Alder bonsai sunlight requirements

The alder bonsai needs plenty of sunlight because it thrives well outdoors.

How fast do Alders bonsai grow?

Alder trees in general are fast-growing trees that have a lifespan that lasts for 60 up to 70 years. There are even alder trees that can survive for as long as 100 years.

The alder bonsai trees are very simple to maintain and grow. Even though some types of alder grow much faster than others, these are long-lived trees that take several years to achieve their maximum height and thickness. You need to be extra patient in this case.

How tall does a Alder bonsai get?

Again, there is no sufficient information on how tall an alder bonsai can get. However, the different species of alder in their natural habitat can grow as tall as 66 to 100 feet.

Alders bonsai types

Alder trees have several distinct species. The specific type of plant will depend on the climate, your place, and your garden space. Below are some of the most common types of alder bonsai:

Red Alder bonsai

Red alder is a medium-sized broadleaf tree with a uniformed textured and moderately dense wood. The edges of its leaves curl within. Its bark also serves as the origin of the color used for garments.

Black Alder bonsai

The black alder bonsai appreciates some shade. The black alder can reach a height of 40 up to 60 feet, and its bark is used for traditional medical treatment. Meanwhile, the wood of black alder is used to produce doors and cabinets.

Italian Alder bonsai

The Italian alder can be used to create a medium to large bonsai. This is a fast grower that responds well to pruning. Its branches also develop great, and the size of the leaves reduces quite rapidly, too.

White Alder bonsai

The white alder is a medium-sized deciduous tree that grows at a height of 15 to 25 meters. Its bark is a pale grey that is smooth on the young trees and turns scaly when the tree gets old. White alders thrive in moist soils. The roots tend to be invasive, so it is important to be careful when choosing where to plant them.

Speckled Alder bonsai

Speckled alder is a type of smaller and often multi-stemmed thicket forming tree suitable to be planted under power lines. Its flowers during early spring are interesting although not that showy.

Witch Alder bonsai

The witch alder is the genus of 2 to 4 flowering plant species in the Hamamelidaceae family native to swamps and woodland of southeastern US. These are low-growing deciduous shrubs that reach a height of 3 to 10 feet with downy twigs.

Its brush-like flowers form in spring before the leaves on terminal spikes. These don’t have any petals and instead, the witch alder has a noticeable cluster of white stamens 2cm to 3cm long.

Can Alder bonsai grow in winter?

There are no details on whether alder bonsai can grow in winter. However, alders can become large shrubs or towering shadow trees that thrive on swampy and damp soil. Alders in the landscape can be recognized easily by their clenched green leaves, brown coniferous cones, and solid circular crown. Alder cones can grow from conical floral clusters or catkins and remain on the trees during winter that gives a unique appearance to the naked branches.

Alder trees in suburban landscapes are quite rare. Due to their wetland inclination, wide canopy, and size, these trees are not ideal for the landscape. Certain types of alders, on the other hand, can be used as amazing hedge shrubs for protection and security.

Alder bonsai winter care

Temperate trees such as alders must have enough exposure to cold weather during fall for them to enter dormancy. It means that you need until the initial frost before you add protection or put your trees in winter storage.

If you are living in a cold area, you should keep your tree in a cold frame or greenhouse during the winter when temperatures drop lower than -10 °C. A cold frame can help reduce temperature fluctuations and protect your trees from significant drops during nighttime. This can also ensure that your trees don’t dry out because of the strong winds.

When this type of shelter is unavailable, you can put some Styrofoam covers around pots to keep the roots protected. You can also plant the bonsai in the garden with the plant included, with soil covering it over the roots. See to it that the trees are placed in an area without excessive wind.

For those in milder climates that have temperatures of about -4 °C during nighttime, there is no need to use a cold frame. However, it is still recommended to keep your trees protected from the strong winds and put them on the ground. Doing so prevents sudden temperature drops. You can also cover the pots of your bonsai with a bed sheet or other types of insulation.

Avoid exposing your trees when dormant to a long period of high temperatures since this might end up bringing them out of dormancy. Your tree will be extremely prone to freezing temperatures once it starts growing and the buds can die off easily which can have a significant effect on your bonsai’s health. For your tree to stay dormant during winter, try opening your greenhouses when they turn warm during sunny days in winter. If your tree is not dormant anymore, protect this from late frosts that might take place.

Keep a watchful eye on your alder trees when overwatering. Water only if the soil turns dry. Your trees don’t require a lot of water when dormant so avoid watering too often. Check the trees for infections and insects regularly. Take the trees outside again when spring comes but stay alert to offer protection to the new growth against the late frosts.

Is Alder bonsai a nitrogen fixer?

Yes, an alder bonsai is a nitrogen fixer. The alder trees exhibit bi-level functionality that meets not just their own needs for growth, reproduction, and survival but also for humans and meeting the ecosystem’s needs.

Alders are ecologically vital for fixing the atmospheric nitrogen to a usable form for the plants as an early pollen source for bees and for controlling erosion on riverbanks.

Do Alder bonsai trees bloom

Yes, alder bonsai trees bloom. These bonsai trees are in demand for their early spring flower show and their hardwood at the same time. Alders are wide leafy trees that have floral clusters and strobiles, or brown woody cones.

Is Alder bonsai toxic to cats and dogs

There is no information if alder bonsai is toxic to cats and dogs. However, while most bonsais are not harmful to domestic animals, it is still important to be extra careful.

Many bonsai gardeners don’t settle on particular varieties of bonsai that can be considered safe, and this is because most of the time, animals and bonsai trees can share a similar environment with no issues.

The main point here is to keep your alder bonsai out of your cat or dog’s reach and avoid leaving your pets unsupervised for a long time to stay safe.

How to make a Alder bonsai tree from cuttings

  1. Prepare your bonsai pot then fill this about 2/3 of the way up with the bonsai soil mix.
  2. Be careful in taking the cuttings from the parent tree. It is recommended to take 2 to 4 cuttings with a length of 7cm to 10cm to ensure success.
  3. Clean your shears first. Take the cuttings then cut a 45-degree angle on the stem with a clean cut.
  4. Trim off most of the leaves from the branch and leave only a few.
  5. Water the bonsai soil to keep it moist.
  6. Put the cuttings in the bonsai pot and push them straight at a depth of one inch.
  7. Water over the cuttings regularly in the next several months. Put the bonsai pot in a place where it can receive plenty of sunlight to promote healthy growth.

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