An Extensive Care Guide for Redwood Bonsai

Redwood bonsai trees make perfect centerpieces or background specimens in the garden, thanks to their long, slim, upright trunks that grow incredibly tall. This particular feature makes them suitable for large-sized bonsai trees. 

That being said, if you’re ready to grow a tall bonsai tree that can add dimension to your display…

Read on to know:

• The nature and growth habits of redwood species.
• Propagation techniques for redwood or sequoia bonsai.
• Two redwood tree species that are suitable for bonsai art.
• The proper and ultimate redwood miniature tree care and maintenance guide.
• And that’s only the beginning…

What is a Redwood Tree?

Botanical name:	Sequoia or Sequoioideae
Family:	Cupressaceae (Cypress)
Tree type:	Coniferous evergreen/deciduous tree
Foliage type:	Needle-like or scale-like with either opposite/alternating pattern
Growth habit:	Upright
Native habitat:	China, and Pacific coast of North America & Oregon
Distinctive feature:	Reddish-brown, scaly bark & tall, upright trunk

Redwood species are the tallest upright trees in the world, reaching up to 98.4 ft (30 m) tall. They are also fast-growing specimens; each year, they grow more than 3.2 ft (1 m) high.

While some are deciduous, and others are evergreens, all redwoods have a soft needle or scale-like long foliage. They also have pretty similar growth habits and characteristics. Their most notable features are their mature reddish-brown bark that peels off in narrow strips as they age.

In March or early spring, they produce flowers that turn into cones similar to other pine trees. However, these flowers and cones don’t play a major role in the overall aesthetics of the tree. One of the reasons for that is that only older trees, particularly 30 years old and above, can produce such. 

Redwood Species Cultivated for Bonsai

There are three types of redwoods: Giant sequoia (Sequoiadendron giganteum), dawn redwood (metasequoia glyptostroboides), and coastal redwood (sequoia sempervirens). However, only the last two are often cultivated for bonsai art because they are more manageable.

The dawn redwood tree species originated from China. It’s dubbed a “living fossil” because it was first discovered in Sichuan, China, in 1941 based only on fossil proofs, which made scientists believe that it was extinct then.

Dawn redwoods are strong, tall, upright deciduous trees with green needle-like foliage with opposite leaf patterns. Its leaves turn rusty-orange color before they drop in the fall.

On the other hand, coastal or coast redwood species are native to the Pacific coast of North America and Oregon. It’s recognized as the tallest type of tree in the world, with some specimens in California reaching more than 330 ft (100 m) tall.

Trivia: “Hyperion” is the recognized world’s tallest coast redwood tree at 380 ft (116.07 m) tall.

Coast redwoods are evergreen trees with two types of foliage: scale-like and needle-like. Scale-like leaves grow on main shoots, and needle-like leaves grow in new shoots.

Growing redwoods as bonsai (propagation redwoods)

You can propagate coast or dawn redwood trees by planting seeds, cuttings, or air-layering.

Since redwoods have upright trunks and grow very tall, they’re best styled as large-sized formal upright bonsai trees. Although they’re huge specimens, redwoods are easy to care for, making them suitable even for beginner bonsai artists.

How to Care for a Redwood Bonsai Tree

The challenging part about cultivating redwoods is that their growth is not easy to control, so you’d have to do regular pruning, trimming, and repotting.

If you want to grow one, check out this Coast and Dawn redwood miniature tree care guide:

Quick general care guide for redwood bonsai trees:

• Positioning: Place outdoors in the full sun year-round in temperate regions.
• Watering: Water as soon as the soil surface becomes slightly dry.
• Feeding: Fertilize throughout the growing season using a high-nitrogen product.
• Pruning: Prune 2 to 3 times a year in the spring, early summer, or late fall/early winter.
• Wiring: Wire and bend after pruning sessions for convenience and safety.
• Repotting: Repot every 2 years in mid to late spring as the buds swell.
• Overwintering: Provide winter protection once the temperature drops below 32°F (0°C).

I. Positioning

Since they naturally grow in the forests, redwood miniature trees thrive outdoors, exposed to the full sun.

However, once the temperature hits above 85°F (29.4°C) in the peak of the summer, you should protect it from the intense sun by placing it under a shade cloth that offers 20% sunlight filtration.

Important: Placing it under shade for long periods encourages larger leaf size and longer inner nodes, which can eat up more energy and weaken your bonsai. 

Although not encouraged, growing indoors is also possible if you provide your sequoia bonsai with the right conditions, such as direct sunlight for a few hours a day, high humidity, and frequent watering.

II. Watering

Redwood miniature trees love water, especially coast redwood species, since they grow naturally along the Pacific coast. Hence, watering them frequently and keeping their soil moist will benefit them. 

Keep pouring water until it runs out of the pot’s drainage holes, and repeat the process to ensure that the entire root ball is watered. Do it once you notice the top layer of the bonsai soil becomes slightly dry. 

Tip: Using a moisture meter can help you monitor the proper moisture levels and determine exactly when to water your bonsai.

Watering redwoods based on the season

Proper watering is important in keeping your redwood miniature tree in tip-top condition. Here’s a guide on when you should increase or decrease its watering frequency:

A. In spring

As your coast or dawn redwood miniature tree produces new growth, its watering needs increase. Check your bonsai at least twice daily and water as necessary.

B. In summer

Their watering needs further increase as the temperature gets hot. During this season, water your bonsai at least twice a day—once in the morning and another in the late afternoon. You can also water it between those times once you notice its soil drying out. 

Warning: However, be cautious not to overwater it as this can lead to root rot.

To help increase the humidity in the area, place it under a tray filled with water. You can also wet its stand and surrounding pavements to cool the area.

C. In autumn and winter

Your bonsai keeps moisture longer during these months. Thus, you should decrease your watering frequency to a few times a week—only when needed.

III. Fertilizing

Fertilization is essential when growing redwood miniature plants, especially those grown from seeds, cuttings, or air-layering. Doing this allows them to grow a few years faster than growing naturally.

For best results, fertilize your sequoia or metasequoia bonsai during the growing season.

Feeding redwoods based on their needs

Depending on the need of your bonsai, here’s how you should fertilize it:

A. For health enhancement

Use a high-nitrogen fertilizer in the spring to encourage the strong growth of new buds and enhance the health of young specimens.

B. For general development and refinement

In summer, decrease the number of bonsai fertilizers to avoid encouraging uncontrollable growth.

IV. Pruning

Coast and dawn redwood bonsai trees don’t need much branch pruning compared to other bonsai species since they naturally grow upright. 

However, pruning their twigs with long internodes is necessary 2 to 3 times a year to control their growth and maintain their shape. Take note that you can only prune older trees with lignified growth.

Here’s a guide on when you can safely prune back your redwood miniature tree:

• In spring—before the new buds open
• In early summer—after the buds have hardened
• In late fall/early winter—once it sets its new buds for the next season

Note: Redwoods tolerate pruning very well, and they even produce new buds near scars, so it shouldn’t pose any concerns.

V. Wiring and Bending

You can do wiring and bending of branches in the same season as pruning—spring, early summer, or late fall/early winter.

Although the branches of older species can be quite brittle, they remain flexible for a long time. Hence, you can still bend them heavily if you do it cautiously. You may also use guy wires for extra support. 

Note: Use an annealed copper bonsai wire when wiring the branches of your redwood miniature tree, and apply it tightly at 60 to 65 degrees angle for proper support.

VI. Repotting

Coast and dawn redwood miniature plants have strongly-growing roots that can quickly fill up a shallow bonsai pot. That said, repot your redwood miniature tree every two years in mid to late spring—when the tree is active and the buds are swelling.

Root pruning

Prune the roots as well to control the growth of the tree. To do that, remove some of the soil from the root ball using a root rake, but never remove all of the soil, as this can be detrimental to the tree. Then, cut the roots using a root cutter.

Soil requirements

Use fresh soil when repotting your bonsai. Choose a mix that can keep the root system moist for a good amount of period but also one that can drain excess water to avoid root rot.

VII. Winter Care

Sequoia and metasequoia bonsai don’t tolerate freezing temperatures below 32°F (0°C). 

Hence, you should protect your bonsai against frost and cold conditions during the winter months. You can temporarily move your redwood miniature tree to a greenhouse, cold frame, or unheated room.

Warning: Exposing your bonsai to cold temperatures for long periods can lead to the dieback of roots and branches.

VIII. Pests and Diseases

Redwood miniature tree species are hardly attacked by pests and diseases when grown in the right conditions. Ensure your bonsai receives sufficient sunlight, frequent watering, proper fertilization, and regular maintenance to keep it thriving. 

Suppose it got infested or infected, apply an appropriate insecticide, pesticide, or fungicide immediately at a proper dosage.

Conclusion

Redwood trees are great specimens for large, upright bonsai plants. Although they’re particularly larger than other species, they are quite easy to care for and don’t require extensive maintenance. 

As long as they’re cared for properly, redwood bonsai trees can live and thrive for several years.