Care for bonsai tree

Juniper Bonsai (Juniperus)

The juniper is a genus of about 50 – 70 species within the cypress family. They are evergreen coniferous trees or shrubs, which are very popular for Bonsai purposes.

Juniper Bonsai trees sold at large stores, including Walmart and Home Depot, are often Japanese Garden Junipers, also called Green Mound Junipers (Juniperus procumbens nana). Other popular species are the Chinese juniper (Juniperus chinensis), the Japanese Shimpaku (Juniperus sargentii), the Japanese needle juniper (Juniperus rigida), two central European species: the savin (Juniperus sabina) and the common juniper (Juniperus communis), and three American species: the California Juniper (Juniperus californica), the Rocky mountain Juniper (Juniperus scopulorum) and the Sierra Juniper (Juniperus occidentalis). All these species have similar care guidelines.

The foliage colors range from dark blue-greens to light greens and the foliage can either be scale-like or needle-like. Scale junipers usually have needle-like foliage when they are young (called juvenile foliage), the typical scale-like foliage appears later. After heavy pruning or bending, overwatering or other stress often juvenile foliage will grow again. It can last a few years until enough normal scale-like foliage has grown and all the needle-like foliage can be removed.

The berry-like cones are round or oval, depending on the species they measure around 2 cm (1 inch), sometimes down to 3mm, and they need a year or two to ripen. The seeds are round or edged. The cones are often eaten by birds who spread the germinable seeds later with their droppings.

Junipers are very suitable for creating deadwood (jin and shari). This is due to the fact that live veins below a broken or for other reasons dying branch will dry out and die. This results in natural deadwood which is peeled, polished and bleached by climatic conditions and is very durable in case of the juniper. The triad of green foliage, reddish-brown or yellowish-brown bark and silvery white deadwood is very appealing.

Identify your juniper species

There are two groups of Junipers, one with scale-like foliage and the other one with needle-like foliage.

The two most popular juniper species for bonsai of the group with scale-like foliage are the Chinese Juniper and the Japanese Shimpaku (which is a variety of the Chinese Juniper which was originally found in the Japanese mountains). Both have scale-like foliage with a color ranging from yellowish-green to bluish-green or grayish-green. The Itoigawa Shimpaku is very popular due to its delicate emerald-green foliage. There are numerous varieties and cultivars of the Chinese Juniper many of which are not easy to distinguish with certainty, care guidelines for these varieties are highly similar. The Savin is a juniper from southern Europe, North-Africa and some parts of Asia with scale-like foliage which can be finer or coarser and of different shades of green depending on its origin. All parts of the Savin are poisonous. The California Juniper is native to California and has bluish-grey scale-like foliage. In nature it grows as a small tree or shrub. The Rocky Mountain Juniper grows in western North-America and can become a tall tree. Its leaves are scale-like, quite coarse and can be dark green or bluish-green. The Sierra Juniper is a shrub or tree native to the western United States, growing in mountains at altitudes of 800–3,000 meters (2500 to 10000 ft). Its leaves are scale-like and grayish or dark green and tend to grow quite dense.

There are also popular juniper species with needle-like foliage. The Japanese Needle Juniper has sharp, dark green, stinging needles with a narrow white line along their length. The Green Mound Juniper Bonsai is also from Japan and also bears needle-like foliage, but the needles are shorter, more compact, bluish-green – almost like scale-like foliage. This plant grows as a ground covering shrub if it is not shaped. The Common Juniper in native to Europe, North-America, Asia and North-Africa. Its needles are sharp but smaller and more delicate than those of the Japanese Needle Juniper. In nature it grows in a columnar shape or as a depressed shrub.

If you need help identifying your tree, try our Bonsai tree identification guide.

Video: Juniper Bonsai trees

Specific Bonsai care guidelines for the Juniper Bonsai

Position: Place the tree outside, year-round, on a bright spot with lots of sunlight. The Juniper cannot live indoors. During the winter protect the tree once temperatures drop below -10 degrees C (14F). Some species change their foliage color during frosty periods to a purplish brown which is connected with their frost protection mechanism. In spring they will turn green again.

Watering: Be careful not to water too much, as the juniper roots don’t like soil wetness. Before you water, the soil should dry slightly. Misting the tree can be done regularly, especially after the tree has been repotted because it benefits from air humidity. Continue reading about watering Bonsai trees.

Feeding: Use normal organic fertilizer pellets or balls every month during the growth season or a liquid fertilizer each week. If strong growth is desired some higher nitrogen levels can be applied in spring.

Pruning: To develop the foliage pads, long shoots which stick out of the silhouette can be pinched or cut at the base with sharp scissors throughout the growth season. Do not trim the juniper like a hedge because the removal of all growing tips will weaken the tree and the cut will turn the needles brown. When the foliage pads become too dense they must be thinned out with sharp scissors at the base. The Juniper Bonsai is generally a strong tree that also withstands aggressive pruning quite well. But it cannot bud again from bare tree parts, so take care that there is some foliage left on every branch you want to keep alive. Continue reading about pruning Bonsai trees.

Wiring: Junipers which are produced for Bonsai purposes are already wired quite heavily in most cases when they are still very young. Dramatically twisted shapes are very popular and correspond with the natural shapes that used to grow in the Japanese mountains in former times. Junipers can be strongly bent, if necessary wrapped with raffia or tape as a protection, but you must be careful with parts which possess deadwood. Those parts break easily. If they are large and old, you can split the deadwood off in order to bend the more flexible living parts. The foliage pads should be wired and fanned out after thinning when necessary, to let light and air get in. Otherwise the inner parts of the foliage pads will die. In addition to this, the danger of pest infestation is increased if the pads are too dense. From the aesthetic point of view we also want to achieve unobstructed structures and want to prevent the juniper from looking like broccoli.

Repotting: Repot the Juniper Bonsai tree once every two years, very old trees at longer intervals, using a basic (or somewhat more draining) soil mixture. Don’t prune the roots too aggressively.

Propagation: Use seeds or cuttings.

Acquisition of juniper Bonsai: Many well-suited juniper species in different sizes are offered in most nurseries. You can often find good Bonsai raw material there. In gardens, concrete pots and on cemeteries on old graves that will be cleared there are often quite old junipers and if you are lucky the owner will allow you to dig one out for little money or a new plant. Specialized Bonsai traders offer everything from young plants, pre-Bonsai and pre-styled juniper trees up to high-value Bonsai, in various styles and shapes.

Pests / diseases: If junipers are well cared for and placed in an ideal position they are quite resistant against pests. It is important though not to let the foliage pads get too dense, because otherwise pests can settle in them more easily. During winter the junipers must be kept in a place with enough light and they must be checked for pests regularly because pests can even occur in winter. Junipers can sometimes get infested with spider mites, juniper scale, juniper aphids and juniper needle miners as well as juniper webworms for example. Customary insecticide / miticide sprays will help but you should also find the reason why the tree was prone to infestation. A big problem are fungal rust diseases. The diverse juniper species and cultivars have a very different level susceptibility to rust fungus, there are also some which are regarded as resistant. As a rule of thumb, the blue-green junipers are more resistant than those with yellowish-green foliage. The Japanese junipers are also not infested very often. In the internet you can find files which list many juniper species and cultivars and their susceptibility / resistance level to rust fungus. The rust fungus infests the junipers permanently and causes swellings from which hard, brown galls emerge. In spring, during rainy weather, the galls produce large, orange, gelatin-like tendrils, full of spores, which infest the leaves of pear trees (but there are also types of rust fungus which use hawthorn or crabapples as a second host instead of the pear). The fungus causes orange spots on the pear leaves. In late summer brownish proliferations grow from the bottom-sides of the leaves which release spores that infest junipers again. While the pear trees in most cases are not fatally affected – they are newly infested each year again and they can even be treated successfully with a fungicide, an infested juniper normally cannot be cured. The visibly infested branches die in most cases and the fungus can emerge on other tree parts. Removing the parts with the swellings and galls is no guarantee at all that the fungus will not reappear. Although some people have a different opinion, it is best to immediately burn up a rust-infested juniper or put it into the garbage instead of your compost heap.

For more detailed information on these techniques, try our Bonsai tree care section.

Juniper Bonsai

This miniature tree is a lush green, low growing Juniper, and is the most popular plant used for bonsai. Your help is needed, however, to keep it alive. Please follow the instructions below carefully. Note especially the placement instructions.

Placement:

Your bonsai may be grown either indoors or outdoors. Indoors, situate it where it will receive bright light with three or more hours of direct sunlight. If outdoors, place in light shade where it is protected from the wind. It is best to move the bonsai outside in the spring after minimum night temperatures exceed 40ºF and return it indoors in the fall before the first hard frost.

During winter months indoors, your bonsai will do best in a draft-free, bright, cool, humid room with night temperatures of 40º-55ºF and daytime temperature below 60ºF. Extra humidity may be provided by frequent misting or by setting the plant in a decorative tray filled with pebbles and water added to a level just below the bottom of the pot.

Watering:

A bonsai plant requires frequent watering. You should plan to water it every two to three days. Never allow the soil to dry out completely. Usually you can tell when it needs watering by the color and feel of the soil surface. The soil color lightens as it drys and the surface feels dry to the touch when it needs watering. After watering, the soil color is a deep chocolate brown.

To water, place the plant in a pan with 1″ to 2″ of water and soak for an hour or so until the soil looks and feels moist. If you are unable to water it for several days, you can enclose the pot in a plastic bag (the way we shipped it to you) immediately after watering. The bag acts as a greenhouse and will keep the soil moist for at least a week.

In some regions salts and minerals will build up on the surface, discoloring the soil. Either spray the soil surface with water, or submerge the entire pot in water to flush out the buildup.

Pruning:

A fundamental principle in developing dwarf trees is that the tree branches should be pruned to conform with the limited space available for root growth. Without pruning back the branches, the tree would grow too large to be supported by the confined root structure.

To prune, pinch out ends of new growth about once every six weeks while they are growing. In pinching and pruning you are trying to maintain the shape of the bonsai and to create more bushiness.

Root Pruning:

Every other Spring (March-May) your bonsai will need its roots pruned. Gently remove the plant from the pot, carefully remove some of the soil around the sides and bottom of the rootball. Cut off one-third of the roots all the way around and up from the bottom. Place fresh, porous soil in the pot (a houseplant soil mix is suitable) and replant the bonsai. After potting, mist the plant with water and soak it in a solution of water and Vitamin B-1 transplant shock treatment.

Insect Control:

Spray once a month with household plant insecticide. Bonsai are especially susceptible to mites. Even though you can’t see them DO SPRAY since they multiply rapidly, sucking the juices out of the plant and eventually killing it.

Fertilizing:

The plant should be fertilized every six weeks between spring and mid-summer, using regular houseplant food at half strength.

Toxicity:

Plant material such as this product should not be eaten. While most plants are harmless, some contain toxins.

How Bonsai Works

­Although a bonsai tree can be grown from a seed, started from a cutting or harvested in the wild (in areas where you can get permission to do so), the most common way to obtain a new plant for bonsai is through a reliable nursery. Start looking for a tree or shrub for bonsai in early spring. Choose a specimen that is 6 to 8 inches tall (15 to 20 cm) and has a strong, tapered trunk that is free of scars and blemishes . The style you have in mind for your new bonsai tree, like upright, slanted, cascade or another traditional form, will help you select a plant variety with a good basic shape and the characteristics you need. Pruning and wiring bonsai is usually started in the second year and onward, but selecting a good basic shape will save you time and extra work later.

Choose a pot that will complement the color of the foliage and balance the tree’s emerging design. Bonsai pots are typically shallow and always include drainage holes. The pot and tree work together to create the bonsai design, and although a bonsai tree may be planted in many pots during its life, each pot helps create balance and harmony in the overall design.

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After choosing a specimen, potting the young tree is the first step in transforming it into bonsai. The following steps will help you turn a tree, shrub or other plant into a bonsai-in-training. The process of growing a true bonsai will take years, but these first steps are important because they will help your tree adjust to a shallow pot and a smaller root system.

  • Make sure the young plant is well-watered before potting.
  • Prepare the pot by feeding a length of small gauge bonsai wire through the drainage hole to support the tree until it becomes established.
  • Place a thin layer of gravel in the bottom of the pot for drainage, temporarily blocking the drainage hole if too much gravel escapes.
  • Remove the bonsai tree from its old pot, and remove the soil from around the roots. A bonsai root hook and rake can help make this part of the process easier.
  • Inspect the roots, discarding any dead or damaged bits.
  • Trim the roots by about two thirds. This seems extreme, but controlling root growth is an essential element in creating and maintaining bonsai. Given time and care, the tree will adjust to its new circumstances.

To continue with water, soil and sun for your bonsai, head over to the next page.

Juniperus/ Juniper Bonsai Species Guide

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Junipers/Juniperus

Along with Pines and Japanese Maples, Junipers are one of the three most frequently used genera for bonsai. Juniperus is a genus of 50+ species of evergreen, coniferous shrubs from dry forests and hillsides throughout the world.

Junipers have foliage of two types, needle-like juvenile foliage and scale-like adult foliage, species that exhibit predominantly one or the other are used for bonsai cultivation. The range of colour of the foliage ranges from steely-blue-greens to light greens occasionally with silver or gold hues.

Most of the classic Juniper bonsai in Japan have been collected as yamadori from the mountains and can reach ages of 200 years or more. Many display large amounts of natural and artificially created deadwood called jins and sharis which are bleached brilliant white with lime-sulphur.

The immature, or needle-like, foliage of a Common Juniper (Juniperus communis).

Common Juniper bonsai (Juniperus communis).

The mature, or scale-like, foliage of a Juniper sabina bonsai (Juniperus sabina var. sabina).

Juniper sabina bonsai (Juniperus sabina var. sabina).

Species and varieties suitable for bonsai

The classic Juniper for bonsai is often referred to as the Chinese Juniper. This is a naturally occurring hybrid species called Juniperus x media which is a cross between J.chinensis and J.sabina. (Confusingly Juniperus x media is also referred to in some textbooks as Juniperus pfitzeriana).

The foliage can have a mixture of adult and juvenile foliage and as this combination can disrupt the design of a bonsai, so varieties of J.media that display only one form of foliage tend to be used. Juniperus x media ‘Blaauw’ (named by a Dutch nursery ‘Blaauw & co’) is a strong growing conifer which carries bluish grey-green scale-like adult foliage. As with other J. x media, if needle-like juvenile foliage appears it can be pinched out until adult foliage appears.

Another very popular species for bonsai is Juniperus rigida, the ‘Needle Juniper’. As the name suggests J. Rigida has sharply pointed needle foliage as has Juniperus communis a plant found growing wild in many parts of Europe, though it should be noted that collected J.communis is notoriously difficult to keep alive for more than 2 or 3 years after collection.

Juniperus squamata (needle foliage), J.sargentii (scale foliage), J.chinensis, J.Sabina, J.horizontalis procumbens, J.communis hornbrookii are also popularly used as are dozens of other species and varieties.

Other Juniper varieties often used for Bonsai

Shimpaku or J. sargentii

The Shimpaku is a Chinese Juniper variety with bright green new foliage that fades to a darker green when mature. The tree has naturally dense and compact foliage which is excellent for bonsai.

As with a number of Juniper varieties, the foliage can turn a brown or bronze colour after frost and will remain so until Spring when it turns back to a more familiar (and healthy-looking) green.

Blaaws Juniper or J. x media ‘Blawii’

The Blaaws Juniper is more vigorous than the Shimpaku but has less naturally well-ramified growth. In comparison, the green foliage has a blue-grey tint.

Sabina Juniper or J. sabina

Common to Europe and similar in colour to the Shimpaku, the Sabina has looser but finer foliage that requires continual pruning of vigourous shoots to encourage ramification.

San Jose Juniper or J. chinensis ‘San Jose’

A Juniper with blue-green foliage and beautiful red bark, more commonly found in the United States. The San Jose is reluctant to form uniformly adult/scale foliage and on occasions enthusiasts will opt to develop with juvenile/needle foliage only.

Blue-Rug Juniper, Creeping Juniper or J.horizontalis

A very common Juniper variety sold in garden centres and shopping malls across the world, J. horizontalis has very weak trunks and branches leading to a naturally horizontal, creeping growth habit. Predominantly mature/scale foliage in a range of colours from dark green to steel blue (depending on the specific variety). Trunks are very slow to thicken.

Himalayan Juniper or J. squamata

Very commonly found growing in European gardens and nurseries, J. squamata carries juvenile/needle foliage only in a wide variety of colours, depending on the variety. Very vigorous, fast growing and responsive to bonsai techniques but its appearance suffers from the retention of old needles that steadfastly remain on the tree after dying and browning off.

Common Juniper/J. Communis

J. communis is the only truly native Juniper in the UK. A needle juniper with dull-green foliage, the Common Juniper has a terrible reputation for dying inexplicably 2-3 years after collection however garden centre/nursery specimens appear to be far more robust.

Bonsai cultivation notes

Position Full sun though Junipers with predominately scale-like foliage benefit from a little shade from the midday sun. During winter protect during frosts below -10°C but coniferous trees should not be over wintered in dark outbuildings unless temperatures are consistently below -10°C, at this point there is no requirement for light.

Never try to grow Junipers indoors, though they may seem to tolerate indoor cultivation at first, poor humidity, lack of light and dormancy will eventually kill them. Do not trust a vendor, seller, book or website that claims Junipers can be grown successfully indoors. Dead Junipers can continue to display normal foliage colour for weeks or even months after they have died at the roots.

Watering Ensure Junipers growing in poor, compacted organic soils are not over watered as they suffer root rot easily, foliage should be misted frequently to help keep pores free of dust enabling them to breathe. In the case of trees that have been recently repotted or have root problems, misting is essential as conifers are able to absorb enough water through their leaf surface to maintain health until the roots are able to support the tree themselves. Misting also avoids excess transpiration and water loss on hot summer days.

Feeding Feed fortnightly; high nitrogen fertiliser from start of growth in Spring until mid-summer and a balanced feed until late summer until winter. Occasional replacement feeds with an acidic fertiliser such as Miracid are highly recommended, particularly in hard (lime) water areas.

Repotting

Repot in April-May, do not repot or root-prune too early in the year. It is always better to wait until the tree has started into growth before repotting. Can also be very successfully repotted during the warmth and humidity of August, however avoid repotting during very hot days.

Once established in a good quality soil, repot infrequently every 3-5 years. Never bare-root a Juniper or change more than a third of the soil (or at very most half) in any one repotting.

An inorganic-clay based soil is essential for Junipers as they are prone to very poor-health in old, compacted, organic soils. Because Junipers cannot be bare-rooted or have more than one third of the soil mass changed in one year, it is essential that a soil with good particle structure is used. Avoid Akadama and similar low-fired clays that break down after one to two years.

Wiring

The wood of Juniperus is extremely flexible and branches of several centimetres in diameter remain supple enough to be shaped with ease. Junipers can be wired at any time of the year including the semi-dormant period of Winter. Do not create heavy bends in trunks and branches during temperatures of 0ºC or less.

For a well-defined Juniper bonsai, the entire tree will require 100% wiring at least once in its lifetime.

The setting time for newly-wired branches depends on the thickness and the vigour of individual shoots; expect anything from 3 months to a year. The greater the amount of growth that emerges from a shoot, the quicker it will thicken and set into its new position. The thicker a branch is, the longer it will take to set.

Watch for wire suddenly cutting into the bark during the Summer as the wood will thicken dramatically during this period, however, shallow wire-marks are not a great problem and will disappear within a few months to a year (again depending on the strength and vigour of the individual branch).

Green Mound Juniper Care

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General Background:

Considered a very hardy conifer, the Juniper is a non-flowering tree that makes a great choice for bonsai because of it is so easy to prune and train. Originating from China, it is one of the most popular types of bonsai trees and is a firm favorite of many bonsai enthusiasts. There are many different varieties including: Japanese Garden Junipers, Green Mound, Sargent’s, Needle, Shimpaku, and Chinese Junipers; all varieties being equally beautiful. Junipers are also one of the easiest forms of bonsai to take care of. Following a few simple guidelines allows a Juniper Bonsai to be grown without difficulty; as such, they are perfect for beginners and will enable one to develop their bonsai into a magnificent work of art with only a little patience and tender loving care.

Trees Features:

The Juniper is a low growing plant, producing lush greenery and small, firm, silvery blue berries atop interesting bark that adapts well to several creative forms of Bonsai bark manipulation. Its compact foliage makes it one of the best candidates to become a Bonsai. Junipers grow slowly and are very long-lived. This Juniper will grow with outstanding beauty, remaining green throughout the year.

Temperature:

An advantage to using the Green Mound Juniper for Bonsai is that because of the degree of hardiness, this tree can remain outdoors, even in the winter months; although it should not be exposed to temperatures below 35 degrees. One of the most important aspects of growing the Juniper outdoors is that the root ball should be carefully protected from frost, as should newly wired or trained trees. Juniper Bonsai should be kept in a cooler environment during the winter months in order to experience a winter rest period in order to maintain good health. During this period your bonsai should be protected from drying winds and extremely cold conditions. Green Mound Junipers are considered outdoor trees. They require a great deal of direct sunlight, changes in temperature, and humidity. When kept outside it can tolerate just about any condition, but don’t let it freeze and make sure it gets afternoon shade in the summer.

Lighting:

Filtered or shaded sunlight outside is best for your Juniper bonsai. Allow your Juniper bonsai to get low intensity morning sunlight when possible and avoid the direct afternoon sunlight. Green Mound Junipers love lots of bright light with a minimum of four hours direct sunlight a day. This type of juniper tree will grow best in full sun to semi-shade, making it easy to find an acceptable place for it to thrive.

Watering:

Junipers, as with most bonsai, like to dry out between being watered. You will want to feel the soil every day in order to assess its moisture levels. If there is a rock in the planting lift it up and feel under it, otherwise, just stick your finger about a half of an inch to an inch into the soil. If the soil feels dry, it is time to water your bonsai. You will want to ensure that your Juniper is not allowed to go completely dry for extended periods. When you water your Juniper, water it from the top, wait a few minutes, and water it again. Repeat this several times to insure that your bonsai has received a thorough watering. Humidity around your Juniper bonsai may be maintained by the use of a humidity tray filled with stones and water. Place your Bonsai on top of the stones in the tray. The tray or plate will also offer protection from the draining water of your freshly watered bonsai. Misting once a day will also help…but remember, misting is not a replacement for watering.

Fertilizing:

Green Mound Junipers need to be fertilized in early spring, using good quality fertilizer. You will also want to fertilize your Juniper Bonsai once every two weeks during the growing season, spring until fall. Use an organic liquid fertilizer such as a fish emulsion or an organic seaweed fertilizer. Organic pellets such as rice cakes may also be used along with regular fertilizers to ensure the best results and produce a happy, healthy, thriving tree

Pruning / Training:

With rapid growth patterns, The Green Mound Juniper is typically seen with long, flowing branches that can be trained in just about any bonsai style with the exception of the broom style.

Most often, the Juniper’s branches respond exceptionally well to wiring and reshaping. Just keep in mind that because the bark tends to be stiff, trying to shape into something other than its natural form can be challenging, although not impossible. Major pruning should be performed only in the springtime or early fall, never during the hot summer months. However, maintenance pruning is acceptable all season long, and on a regular basis, young shoots should be pinched off. To develop the foliage, pinch out the tender new shoots using your fingers. Do not use scissors, as the cut needles will turn brown. Prune undesirable branches (especially those growing straight down from their parent branch) when repotting or during the growing season. Junipers have a low, spread that makes them ideal for cascade and semi-cascade styles. When shaping your bonsai, use the thinnest training wire that will hold the branch in the desired position, taking care to remember that it is never a good idea to wire a bonsai immediately after repotting. Wind the training wire in the direction the branch is bent in order to keep the wire from loosening. Wrapping the wire too tightly will cause scarring. Begin at the base of the Bonsai tree and slowly wrap the wire around the trunk to anchor. Continue along the branch you wish to train. Repeat the process as needed. After about 6 weeks, the branch should be able to maintain the shape on its own, and the wire should be removed. Cut the wire carefully from the branch rather than trying to unwind the wires as this could cause the branch to break. Wiring is best done in autumn or early winter, so that the branches can become accustomed to their new position while the tree is dormant. Wiring done at other times must be watched carefully for signs of wire cutting into the bark, and must be removed immediately if this happens. If necessary, the tree can be re-wired after removing the old wire.

One of the best characteristics of Juniper Bonsai is its hard resinous wood, ideal for advanced sculptural techniques such as Jin, Shari and sabamiki. Because the Juniper tree has needles, that when poked through the skin, can create an allergic reaction, it is highly recommended that you wear gloves to help avoid any red, itchy rash.

Insects / Pests:

Junipers are prone to spider mites. You can spot spider mite trouble by the discoloration of foliage, which will usually turn gray at the tips. If you suspect an infestation of spider mites, you can place a clean sheet of white paper under the branches of your bonsai and gently tap the foliage. If tiny specks will fall onto the paper watch them carefully for a moment and see if any of them get up and try to leave. A moving speck is probably a spider mite. Use a mild insecticide that lists spider mites. It usually will take a few applications of insecticide to get the job done. Spider mites rarely do significant damage. Junipers are also susceptible to fungus problems, especially in shadier, darker and cooler spots. If your Juniper develops discoloration of the foliage that is black or a pale lavender/grayish color, you are safe to suspect a fungus problem. You can easily prevent fungal problems by keeping your bonsai in a well-ventilated area where proper cell growth will be encouraged. Fungus problems are more likely during the dreary, wet fall and winter days and into the soggy spring days.

Propagation:

Because Juniper seeds take up to five years to germinate and are very difficult to grow in that way, most people propagate Junipers from cuttings. In the summer, start softwood cuttings under mist (use a fungicide) and supply bottom heat. Ripe-wood cuttings taken in fall and winter can be started without the mist or bottom heat.

Repotting:

Junipers should be repotted about every two years when young (less than five or six years old) and every three to five years thereafter. Junipers may be repotted throughout most of the year, although, the best times for repotting are in the spring and fall. Gently remove the plant and root ball from the container. If the tree has been wired, simply clip the wire and gently remove. Then, gently trim the root ball using sharp scissors, removing the bulk off from the sides and bottom, usually to about one half inch and taking care to not remove more than one third of the roots. Replant the Bonsai in a clean pot, using well drained soil. After repotting, water thoroughly and keep the plant in a shady location for several weeks so that new roots may grow. The tree should be protected from wind and direct sun for a month or two after repotting.

Additional Comments:

Native Americans, including the Blackfoot, Cheyenne, Crow, and Ojibwa, made tea from the hard berry-like fruits of the Juniper, and used infusions of it to treat kidney diseases, colds and sore throats. They also burned creeping juniper as incense in ceremonies. Modern herbalists and Naturopathic Physicians use essential oils from the related J. communis to treat urinary tract infections, and report that it is useful in treating rheumatism, arthritis and gout. Herbal use dates back to early Greek and Arabian physicians.

DISCLAIMER: The content provided in this article is not warranted or guaranteed by Bonsai Outlet. The content provided is intended for entertainment and/or educational purposes in order to introduce to the reader key ideas, concepts, and/or product reviews. We are not liable for any negative consequences that may result from implementing any information covered in our articles or tutorials. Happy bonsai gardening.

Download this care sheet as a PDF

Green Mound Juniper Bonsai Tree Care Guide (Juniperus procumbens)

It’s easy to understand why the green mound juniper bonsai is one of the most popular bonsai for novice growers. Compared to other bonsai, care and maintenance of the green mound juniper is relatively easy, and it naturally develops the beautiful hunter green leaves and tight growth pattern of classical bonsai.

These hardy trees are tolerant to a wide range of temperatures, and can be adapted to either indoor or outdoor growing.

Scientific/Botanical Name Juniperus procumbens
Description Green mound juniper is an evergreen tree with leaves that are a gorgeous hunter-green color. It displays a tight, compact growth habit.
Position Green mound juniper enjoys a moderate amount of indirect sunlight. This makes it highly suited to indoor cultivation. It will benefit from the low-intensity morning sun if it is given a north-eastern exposure, or kept on a north-facing windowsill. Do not expose the tree to full or direct sunlight under any circumstances.
Watering Green mound juniper likes frequent watering, but it should be allowed to become a little dry before being watered. A number of factors will affect each plant’s watering schedule. Nevertheless, a good rule of thumb is to water the plant when the top one inch of soil has become dry. The most effect means of watering the tree is to place the pot with the tree into a sink or large bowl and add water up to the base of the tree trunk. Let the plant absorb water for a short period: approximately 30 to 60 seconds only. Remove the pot from the water and place it on a rack to ensure thorough drainage of excess water.
Feeding The tree should be fed every two weeks with half-strength fertilizer from early springtime until late-fall.
Leaf and Branch Pruning Pinching-out is the preferred form of pruning for the green mound juniper, and this should be undertaken throughout the spring season and the early part of the summer season. Pinch off new growth when it has reached a length of approximately half an inch. Do this by holding the shoot between the forefinger and the thumb, and giving it a sharp squeeze.
Re-potting & Growing Medium Re-pot green mound juniper every second year until year six. After that, it will need to be re-potted every three or four years. Immediately after re-potting, give the plant a thorough watering and keep it in a darkened location for a few weeks. Re-potting should never be carried out during the period of dormancy, or during active growth.
Wiring The tree tolerates wiring for shaping purposes, and the cascading style complements the natural growth of the tree. Wiring should only be undertaken when the growing season comes to an end, but before the dormancy period. This time frame minimizes the risk of damage to the trunk or branches. Nevertheless, any wiring should be closely monitored.
Notes It is vital that the tree undergoes a period of dormancy each year. This is best achieved by putting the plant in an area where the temperature will remain below 60o Fahrenheit for three months at the very least. An unheated garage would be the ideal location. Even though the tree is hardy, it should be protected from strong winds and extreme frost if it is grown outdoors.

Dormancy

Unlike some other species of bonsai, the green mound juniper requires periods of cold-weather hibernation to remain in stable health. To achieve dormancy, your juniper must be kept below 60 degrees Fahrenheit for a period of at least three months.

Remember, however, that because bonsai are more delicate than their full-grown counterparts, care must be taken to protect them from the elements.

During the winter months, place your bonsai in a cold frame, unheated garage, or other semi-protected environment. While the plant must be relatively cold to achieve dormancy, it should never freeze, or be exposed to strong winds or rain. Do not allow moisture to collect on the foliage or branches of your green mound juniper during its dormancy period.

Light Conditions

The green mound juniper bonsai flourishes under moderate, indirect sunlight, making it an ideal candidate for indoor growing. Position your bonsai in the morning sun, or place it in a North or South facing window to ensure that it receives sufficient amounts of low-level sunlight. Never leave your green mound juniper in full or direct sunlight.

Fertilization

During the growing season, which runs from early spring to late fall, your green mound juniper should receive regular fertilization, about twice per month. Remember that because the bonsai environment is an ecosystem in miniature, your tree does not require a full-strength treatment.

Particularly in the case of chemical fertilizers, it’s generally better to err on the side of caution and administer feedings at one-half the recommended strength for outdoor plants of comparable size.

Watering

Like all bonsai trees, the green mound juniper bonsai must be watered frequently; however, the green mound juniper grows best when allowed to dry slightly in between waterings.

The exact schedule for watering will largely depend on ambient temperature and humidity, but ideally the soil should be dry approximately one inch below the surface, while the bottom-most soil should remain damp.

To ensure that your bonsai receives water evenly, submerge it in a sink or basin until water just touches the base of the trunk. Allow the soil to soak for 30 seconds to 1 minute, and then place the tree on a rack to drain thoroughly.

Moisture

Compared to other bonsai, the green mound juniper prefers a relatively high level of humidity. A humidity plate can help promote a humid environment around the tree.

In addition to adding to the aesthetic appeal of your bonsai, moss placed around the soil can also help trap and release moisture, creating a moister environment for your green mound juniper.

Repotting

Like other bonsai, your green mound juniper will need to be repotted every other year until its sixth year, and every third or fourth year beyond that. Never repot your bonsai during its dormancy period, or during periods of heavy foliage growth.

In order to encourage your repotted green mound juniper to create new roots, water it well and withhold sunlight for a few weeks after repotting.

Wiring And Shaping

The green mound juniper naturally develops as a low-profile shrub, and is therefore perfect for cascading style bonsai. Wiring should always be done in the “off-peak” season, between the end of the growing season and the beginning of dormancy. During this period, it is unlikely that the trunk will develop sufficiently to cause cutting; however, wired trees should always be watched carefully.

Pruning

Pruning for the green mound juniper should take place primarily in the early months of the growth season, during spring and early summer. Unlike many other bonsai species, pruning the green mound juniper is accomplished almost entirely by pinching, rather than snipping.

New growth should be pinched off once it reaches approximately a half inch in length. In order to remove the growth, simply squeeze the shoot sharply between your forefinger and thumb.

Green Mound Juniper – DT2101GMJ

OUTDOOR BONSAI

Outdoor bonsai include evergreen varieties like pines and junipers as well as deciduous varieties like maples and elms. All outdoor bonsai are hardy and require seasonal change. Upon receiving your bonsai, it is best to acclimate it in a shady area for one week. All outdoor bonsai prefer morning sun and afternoon shade. Patios, decks and balconies are great areas to display your bonsai during the growing season. Outdoor bonsai can be displayed indoors, but only for short periods of time. You should never leave your bonsai inside for more than five days.

WATERING PROPERLY

Watering properly is critical to maintaining a healthy bonsai! Outdoor bonsai are watered according to the season. Outdoor bonsai should be watered daily in the spring, summer and fall. In the winter you will not need to water as frequently. However, you should never let your bonsai’s soil dry out. Water your bonsai properly by using a watering can or hose attachment that has a fine-spray nozzle. You should thoroughly soak your bonsai’s soil. Water should be running out of the drain holes. Misting foliage periodically is recommended, but should not be considered watering. General care is also important to maintaining a beautiful bonsai. Bonsai should be periodically trimmed to keep their miniature shape. To best understand trimming and wiring techniques, we recommend purchasing an instructional book.

REPOTTING

Your bonsai will need to be repotted every four to five years. It is necessary to repot your bonsai when its root system becomes pot bound. Repotting outdoor bonsai should be done before new growth appears during late winter or early spring. Make sure you are using a good bonsai soil when repotting since regular potting soil will compact and inhibit proper drainage. We recommend waiting at least one growing season before repotting your bonsai to make sure it is well established.

FERTILIZING

Fertilizing bonsai is required. Most water-soluble and time-released fertilizers work very well when used as directed. We recommend using slow-releasing organic fertilizers for more mature specimen bonsai.

INSECTS & DISEASES

Insects and diseases can attack bonsai just like any other plant. Inspect your bonsai regularly. A brisk spraying of the trunk and foliage periodically will help keep your tree clean. If any problems appear, most garden centers have products available for treatment.

WINTER CARE

Outdoor bonsai need to experience winter dormancy and should remain outdoors in the winter. Nevertheless, the root systems of outdoor bonsai need protection from extreme winter weather. You should “Heel-In” your bonsai by covering the pot and soil with pine needles or mulch when temperatures approach freezing. We also recommend protecting your bonsai from extremely cold winds by placing it against the south side of your house. In areas that have extremely cold winters, bonsai can be protected in garages, sheds, cold frames or basements. Contact a local bonsai club for more advice.

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