Wondering how to care for a juniper bonsai tree?

Although juniper miniature trees are known for being low-maintenance, this shouldn’t be an excuse for anyone to neglect their trees.

Like other species, junipers also need sufficient care and nutrients to grow vigorously, especially when it’s confined in a small pot.

If you’re growing your first juniper bonsai, let me walk you through the entire proper process of caring for it. 

In this bonsai Juniper care guide, you’ll read about:

• Proper juniper miniature tree care guide.
• Background and growth habits of juniper trees.
• 9 common juniper species cultivated for bonsai growing.
• Tips and guides when pruning and wiring a juniper bonsai.
• Juniper bonsai watering frequency depending on the season.
• And that’s only the beginning…

What is a juniper tree?

Botanical name:	Juniperus
Family:	Cupressaceae
Tree type:	Coniferous evergreen tree or shrub with alternating leaf pattern
Foliage type:	Scale-like and needle-like
Growth habit:	Upright or creeping
Native habitat:	Mountains throughout Southwest Asia, Europe, and North America
Distinctive feature:	Deadwood (jins and shari)

Juniper is a hardy evergreen tree or shrub that grows in the wild, particularly in Eurasia and North America.

It’s very forgiving and requires little maintenance, making it one of the most popular trees among beginner bonsai lovers. More than that, it’s highly prized for its beautiful, silvery-white deadwood that makes a good shari and jins.

Additionally, it can be easily propagated from seedlings or semi-hardwood cuttings.

Unlike other conifer trees, junipers produce round, bluish, fleshy cones. Many refer to these cones as “juniper berries” due to their berry-like appearance.

The cones of the common juniper species are edible and often cultivated for culinary purposes.  

As a bonsai, juniper trees are grown as shohin (small) to ogata (large) size bonsai. On shohin juniper miniature trees, long shoots are treated as branches.

They’re often styled in informal upright, slanting, semi or fully cascade forms. You can also find ones with multiple trunks or as a bonsai raft or forest.

Juniper Species Cultivated for Bonsai

There are over 50 known juniper species worldwide, but not all are cultivated for bonsai growing. That’s because not all of them have features that fit the standard bonsai aesthetics.

To simplify our list, let’s categorize the species according to their foliage type: scale-like foliage and needle-like foliage.

Juniper species with scale-like leaves

Scale-like leaves are small leaves that are tightly pressed to the stems. They look and feel like thick, textured shoots.

Note: Some juniper varieties with scale-like foliage have needle-like juvenile shoots.

Here are six commonly cultivated juniper species with scale-like foliage:

1. Savin juniper (Juniperus sabina)
2. Chinese juniper (Juniperus chinensis)
3. California juniper (Juniperus californica)
4. Rocky mountain juniper (Juniperus scopulorum)
5. Sierra juniper or Western juniper (Juniperus occidentalis)
6. Sargent’s juniper or Japanese shimpaku (Juniperus chinensis sargentii)

Juniper species with needle-like leaves

The needle-like leaves of junipers are similar to pines. They are narrow and long and have pointed tips.

Note: Needle-like leaves can also result from overwatering, heavy pruning, and aggressive bending. These leaves can take a few years before they return to their original scale-like foliage form.

Here are three commonly cultivated juniper varieties with needle-like foliage:

1. Common juniper (Juniperus communis)
2. Japanese needle juniper or Temple juniper (Juniperus rigida)
3. Japanese garden juniper or Green mound juniper (Juniperus procumbens nana)

Read also: 17 Easy-to-Grow Evergreen Bonsai Tree Species

How to Care for a Juniper Bonsai Tree

A juniper bonsai can suffer more from getting too much attention (e.g., overwatering) than a few unintentional neglects (e.g., short periods of drought).

Although that’s the case, it’s still important that you provide your leafy friend with proper bonsai Juniper care and maintenance to ensure its strong growth.

To help you out, I’ve created below a complete care guide for juniper miniature tree species.

Quick general care guide for juniper bonsai tree:

• Positioning: Place it outdoors year-round.
• Watering: Allow the bonsai soil to dry out slightly between watering.
• Feeding: Apply slow-release pellets once a month. Then, spray liquid fertilizer bi-monthly or monthly during the growing season.
• Pruning: Can be pruned aggressively during the growing season, but leave some foliage on each branch to avoid dieback.
• Wiring: Can be wired year-round, but best in spring after pruning for convenience.
• Repotting: Repot in early spring, just before the new buds swell.
• Overwintering: Move to a protected area when the temperature drops below 20°F (-6°C).

I. Positioning

Forget everything you’ve read in magazines or blogs that say you can keep juniper miniature trees indoors. The reason is that juniper miniature trees can’t tolerate the poor lighting and low humidity in living rooms, regardless of species or variety.

For your juniper miniature tree to thrive, ensure that it’s getting at least four hours of direct sunlight a day—as sunlight is essential for the plant’s food-making process or photosynthesis. In addition, more sunlight results in tighter foliage and greener leaves.

Since junipers are outdoor species, you can keep them outside year-round. It’s best to place them in a bright location with morning sun and afternoon shade.

Note: Providing your bonsai trees with afternoon shade is necessary, as high heat can damage the leaves. 

Just to clarify: It’s not the direct sunlight but the high temperatures that can harm the foliage.

Don’t know exactly where to place your juniper bonsai?

Then, check out this quick sun direction guide, and adjust your bonsai placement as needed:

• East: morning sun, afternoon shade
• West: morning shade, afternoon sun
• South: sunny mornings and afternoons
• North: shaded mornings and afternoons
• Northeast: little morning sun, afternoon shade
• Northwest: morning shade, little afternoon sun
• Southeast: morning sun, little afternoon shade
• Southwest: little morning shade, afternoon sun

II. Watering

Juniper miniature trees are forgiving and drought-tolerant however, they should never be overwatered or bone-dry, as excess water and prolonged dryness can kill the tree.

For optimal bonsai juniper care, it’s essential to strike the right balance in watering. Ensure you water your juniper thoroughly once the soil feels just a tad dry. To prevent overwatering, always use well-draining bonsai soil and choose a pot that supports adequate drainage.

Here are four techniques to know when it’s time to water your bonsai:

1. By using a moisture meter: Stick a moisture meter to the soil and use it to monitor the wetness of your bonsai.
2. By doing the chopstick technique: Use a wooden chopstick as a replacement for a moisture meter. Stick it to the soil, and ensure it’s touching the bottom of the pot. Then, lift it a few times a day to check the dampness of the soil. If the bottom part of the chopstick is dry, take it as a sign to water your tree.
3. By weighing the bonsai by hand: Compare the heaviness of your bonsai tree by hand when it’s wet and dry, and use it to determine whether your tree needs watering. 
4. By assessing the color of the soil: Instead of weighing your bonsai, you can also just assess its soil surface color. Typically, the soil would appear darker if it’s wet and lighter when it’s dry. 

Watering juniper bonsai based on the season

Juniper trees have slightly varying watering needs throughout the year. That’s why adjusting its watering frequency is also crucial.

To help you out, here’s a care guide on when you should water your juniper bonsai based on the season:

A. In spring

As the temperature slowly increases, the water intake of juniper trees also increases.

With that said, check your tree at least twice a day. Then, water it as soon as the soil becomes slightly dry.

B. In summer

Water your juniper bonsai at least twice a day—once in the morning and again in the evening, as needed. 

Warning: Avoid watering at midday as high heat can cause leaf burn.

You can also mist its foliage to increase humidity.

Suppose you can’t watch your tree at most times of the day. You can place a humidity tray under it to ensure good humidity on hot days. This practice is especially beneficial after repotting a juniper.

C. In autumn

During autumn, water your juniper bonsai tree as needed. Allow its soil to become slightly dry before watering again.

D. In winter

Juniper trees have lesser watering needs during winter. 

Typically, you’d only have to water your bonsai twice a week. However, continue checking its moisture level daily to ensure that your tree won’t dry out.

Warning: Never water your juniper when the temperature is below freezing (under 32°F or 0°C), as very low temperatures can shock the tree’s roots.

III. Fertilizing

Juniper trees typically only need fertilizing during the growing season (early spring to mid-autumn). The reason is that it’s the time when trees absorb more nutrients.

There are two forms of bonsai fertilizers you can use:

• Liquid-type
• Slow-release pellets

Slow-release pellets help avoid root burn since the tree only gets fed every time you water it. On the other hand, liquid fertilizers are used for foliar feeding, which helps boost the tree’s growth.

During the growing season, place slow-release pellets on the bonsai soil surface once a month. Then, apply liquid fertilizer bi-monthly or monthly, depending on the growth stage of the tree.

Warning: Don’t apply liquid fertilizer in hot, sunny weather to prevent leaf burn.

Feeding a juniper bonsai based on its needs

Depending on the primary needs of your juniper bonsai, it may need less or more feeding.

Check out this juniper bonsai care guide for your reference:

A. For health enhancement

Put slow-release pellets on the soil surface once a month or every 4-5 weeks during the growing season. Then, once every two months or every 8-9 weeks in the colder months.

Ideally, you should place one pellet on every 2-square inches of the soil surface. To ensure that all parts of the root system are nurtured, place new pellets in new areas.

Also, you should do foliar feeding bi-monthly.

Tip: Use fertilizers with higher nitrogen content to promote stronger and faster growth.

B. For general development

At this stage, you should avoid overly vigorous growth. To do that, reduce foliar feeding on your tree.

Instead of bi-monthly, you can apply liquid fertilizer once a month during the growing season. Then, again, replace slow-release pellets every 4 to 5 weeks.

To ensure that your tree is well-fed throughout the growing season, apply pellets at the beginning of each month. Then, only begin foliar feeding mid-month.

C. For refinement

Mature juniper specimens don’t need much foliar feeding. That said, apply liquid fertilizer only once or twice per growing season.

However, the application of slow-release pellets should remain the same. That means you should continue to put fertilizer pellets on the soil surface once every 4 to 5 weeks during the growing season.

IV. Pruning

The best time to prune junipers is during the growing season, just as new growths start to appear.

In the realm of bonsai juniper care, while it’s true that this species tolerates aggressive pruning, it’s crucial not to strip away too much of its foliage. Doing so can lead to a weakened tree or, in extreme cases, cause it to die.

Important note: Juniper trees also don’t produce new buds on bare areas, so leave some foliage on every branch you want to keep.

Additionally, prune the leaves at their bases using a pair of sharp scissors. Never on the leaf itself, as it’ll cause dieback and brown tips.

Guide on pruning scale-like leaves:

1. With one hand, hold one piece between your thumb and forefinger.
2. Next, using your free hand, hold the branch to which the piece is attached.
3. Then, remove the piece by gently pulling it towards you. It should come off easily.
4. Continue with the same steps until you reach your desired goal.

V. Wiring & Bending

You can wire a juniper bonsai any time of the year. However, most bonsai artists prefer to do it in spring after pruning the foliage for easier access to the inner branches.

Since it can be bent aggressively, especially young specimens, you can create dramatic twisted shapes on your juniper bonsai tree.

Just check the wires at least once a month to ensure that it isn’t biting in too hard into the branches. 

Wire bit may not affect your tree’s health, but it leaves visible scars on the branches that take time to heal. These scars make bonsai trees appear “unnatural,” which is the last thing you’d want.

Wiring tips & instructions for juniper miniature trees

A. Wiring juvenile or brittle branches

While junipers are amenable to wiring, you should be very careful when wiring juvenile and brittle branches to avoid snapping.

For extra support, wrap tape or raffia strings around the branches you’d want to bend.

B. Wiring the foliage pads

Lack of air and light is one of the common reasons why inner foliage dies.

To prevent that, wire the foliage pads and fan out the small branches in a hand-shaped form. Doing this allows air and light to get through the inner parts of the bonsai. Thus, keeping the whole tree nurtured.

C. Wiring along the deadwood

Juniper deadwood is quite brittle, so wire it gently to avoid it from splitting.

However, if you can’t seem to bend a large and old branch, you can split the deadwood to make the living parts on the same branch more flexible for styling.

You can also watch this video to learn how to bend branches on a big juniper tree:

VI. Repotting

Juniper miniature trees are best repotted in early spring while it’s still quite dormant and the new buds are just starting to swell. That way, you can avoid hurting the tree, especially new growths.

Young plants can be repotted every 2 to 3 years. On the other hand, mature specimens can be repotted less frequently, usually, once the roots start circling the root mass.

You should also consider the soil’s breakdown speed to determine whether your tree needs repotting.

For instance, if you use akadama on a mature specimen, you may still need to repot it in about two years. That’s because akadama breaks down in about two years. Otherwise, your tree will suffer due to poor soil aeration and drainage.

Root pruning

When repotting juniper bonsai, remove as much old soil as possible using a chopstick or root rake. Start from the underside and continue around the periphery. 

Then, prune no more than 30% of the root mass using a pair of sharp scissors.

Except for the savin juniper, which is a strong species, juniper bonsai trees shouldn’t be washed free of soil. 

Soil requirements

Since junipers are sensitive to overwatering, use well-draining bonsai soil.

To accomplish that, you must use bonsai soil components that promote good drainage, such as:

• Grit
• Perlite
• Pumice
• Turface
• Akadama
• Lava rock
• Peat moss
• Pine bark (conifer bark)
• Rice rock (limestone pea rock)

No specific bonsai soil recipe works for all junipers, as each specimen reacts differently to various factors—so feel free to create your own blend.

But if you don’t have the confidence yet to experiment…

You may mix akadama, pumice, and lava rock in a 1:1:1 ratio to achieve a bonsai soil mixture with good drainage, water retention, and aeration.

VII. Winter Care

Since junipers are hardy tree species, it only requires little winter protection.

Once the temperature drops below 20°F (-6ºC), do either of the following to protect its roots from freezing:

• Place it in a cold frame.
• Move it to an unheated room.
• Bury it to the ground up to its first branch.

Since juniper trees still need direct sunlight during the winter months, make sure to move your tree back outdoors as soon as the temperature improves.

Note: Some juniper species turn their dark green foliage to purple-brown in winter when kept outside.

This doesn’t mean that your tree is sick. It’s just your tree’s internal frost-protection mechanism.

Once the temperature rises in spring, the foliage color will turn back to dark green.

VIII. Pests and Diseases

Healthy juniper bonsai trees are very resistant to pests and diseases.

However, weak specimens can be attacked by the following: 

• Aphids
• Fungal rust
• Webworms
• Needle cast
• Spider mites
• Needle miners
• Conifer caterpillars

To ensure that pests won’t settle on your tree, do the following:

1. Don’t allow its foliage to get too dense. Thin them out regularly in spring.
2. Check the tree foliage pads and inner branches regularly in colder months.
3. Ensure the area has good lighting when moving it to a protected spot during winter.

Suppose your juniper bonsai has already been infested, spray traditional pesticide, insecticide, or fungicide onto it. Use ones that address the specific problem of your tree.

Warning: Never spray chemicals on your juniper bonsai in hot, sunny weather, as this causes leaf burn.

You might also like: The Ultimate Guide on How to Revive a Bonsai Tree

Conclusion

Bonsai juniper care is essential, and even though the juniper requires extensive care, it remains a top pick for numerous bonsai enthusiasts.

Its low-maintenance nature combined with its stunning, classic beauty makes it a standout. 

What’s more, its malleability in styling means that if you’re keen on honing your bonsai techniques, cultivating a juniper bonsai tree could be an ideal choice for you.

Remember, by ensuring the right care and nutrition for your juniper miniature tree, you can revel in its robust growth and enduring charm for many years.