Bonsai is a beautiful art form that uses the natural growth of a plant to cultivate it into a miniature version of its full capability. Carefully grown in shallow containers, it is pruned and shaped to create beautiful canopy shapes and colorful blooms. Although they require patience, they are popular with gardeners due to the peace and harmony they bring to the are they are placed in -whether indoors or out.
Cotoneaster, with their small, delicately shaped foliage, make a perfect subject upon which to practice. These plants are hardy and easy to care for with the proper knowledge of how bonsai grow. This guide provides all you need to know about growing cotoneaster as a bonsai, and how to shape and care for it.
Types of Cotoneaster
This plant is a shrub native to Asia. Cultivated as both a ground cover, hedge, or natural bush, these are hardy plants that adapt well in cooler climates and are popular since many are evergreen in nature, and are full of tiny blossoms each spring. There are many different types of cotoneaster, although all are excellent choices for bonsai purposes.
These shrubs are characterized by a low growing profile, some of which get no taller than 8 inches from the ground, and all staying lower than 3 feet tall. These include the popular bearberry, rock spray, and thyme leaf cotoneaster varieties, as well as the cranberry cotoneaster, which is deciduous and is covered in bright red berries through the winter.
When full grown, these varieties could reach 12 feet in height and are popular due to their evergreen appearances. Full of blossoms in spring, these also have vibrant hued berries through the fall and winter. Some of the popular choices include wintergreen, gray-leaved, and spreading cotoneaster shrubs.
Upright and sturdy, these can grow up to 25 feet in height. Considered incredibly hardy, both deciduous and evergreen options are found throughout these varieties, with favorites being the Peking and willow leaf cotoneaster that has showy foliage and berries.
Defining the Term ‘Bonsai’
Bonsai is a Chinese horticultural art form that translates, literally, as “planted in a shallow container”. This idea grew from the practice of placing trees and shrubs that would regularly grow into larger, full-sized plants into small containers that help dwarf the growth process. Through careful cultivation, this results in miniature sized trees that showcase the foliage, texture, root formation, and colors of these plants in a very portable way.
Through the years this practice has become popular with gardeners to place bonsai in their outdoor gardens, as well as indoors – and are perfect for small office spaces and apartments. To truly be defined as a bonsai, the plants need to be carefully formed through pruning and wiring, be placed in an acceptable growing container, and stay under the accepted 4 feet in height. However, some species may reach up to 7 feet. These plants are still allowed to bear flowers and fruits as part of their attractiveness.
How to Grow a Cotoneaster as a Bonsai
The first thing you need to consider is what type of cotoneaster you want to grow. Deciduous choices have fiery foliage in fall and usually a berry through the winter, whereas evergreen choices stay green year round- but ONLY if you provide it cooler temperatures as winter settles in. Otherwise it, too, will lose its leaves.
This is not considered a difficult species to cultivate and like many woody plants can either be grown from seed or propagated from cuttings. Once you choose your variety, decide if you want to start from seed or cutting. A seed can be gathered from ripen fruit and must be allowed to experience the seasons as if it would if left in nature. Allowing it to dry, the cool over the period of a few months in your refrigerator is recommended before planting in a good seed medium.
Propagating a cutting is a fairly simple step as well, and a bit quicker altogether compared to starting from seeing. Cuttings should be taken from semi-mature new growth in mid to late summer. Like most cutting, after dipping in a rooting hormone you should place it directly in a growing medium and allowed to take root over the course of a few months before transfer.
Bonsai soil requirements are very important as they must provide excellent drainage, but also good nutrient binding. Plus, bonsai also exhibits root formation as part of the experience. In order to stunt the growth of your plant without damaging its health, you need to pay particular attention to the soils provided. Soils help split the roots to provide interest, as well as more surface area for moisture and nutrients. It also provides nutrient availability, drainage, and aeration.
Most people prefer to make their own bonsai mix despite being able to purchase a premixed soil. You will need a mixture of organic potting soil, grit, lava rock, pumice, and Akadema- which is a hard, baked clay substance that is excellent for water drainage but also helps bind nutrients.
The Art of the Container
As the name suggests, the container your bonsai lives within is important. The size, shape, colors, and textures must all be carefully chosen to help grow with your plant as it matures, complements its shape, and support the art form. In fact, there are some very specific rules to go by when choosing your bonsai container– all which apply to both as your plant is growing and training its shape, as well as when it is mature and being maintained.
Consider the following when choosing a pot:
- The depth of the pot should be about the same as the thickest part of the trunk directly above the roots. This part of the trunk is called the nebari and this balance is meant to enhance the visual effects between the natural growth and the container it is planted within.
- An oval or rectangular container should be approximately ⅔ around the total height of the tree. A square or round pot should be approximately ⅓ around compared to the height of the tree. You can change the size of the pot as the tree matures or as the canopy becomes wider or taller.
- Fruit-bearing trees can have a slightly deeper pot in order to allow for additional nutrient uptake for the energy needed to grow fruits. Since may cotoneaster bear berries as part of their aesthetic beauty, this is worth considering. If you have a plant that does not bear well despite proper pruning, then you may want to consider a deeper pot.
Taking Care of Your Bonsai Species
Once you have an established, growing plant and the proper container, you need to understand the care of your bonsai. While growing they need specific pruning and shaping to occur which lasted well into maturity to develop its overall form and continued health. Some tips to keep in mind are:
- Remember to use the proper soil substrate and container size to both keep your plant miniaturized, and provide the correct nutrient and water uptake to support this formation.
- Provide a fine mesh along the bottom of your pot to keep solid intact long and to allow nutrients to keep from washing out too easily. The use of Akadema clay helps this as well.
- Although many bonsai end up indoors, make sure they have proper lighting for their species. Cotoneaster can tolerate some shade very well but still requires some sun for part of the day. If lighting is an issue, consider a good grow light for maturing and producing plants.
Bonsai Repotting Tips
Depending on your bonsai, you will re-pot it every 2 to 5 years. This truly depends on how quickly your bonsai is growing, with evergreen varieties growing a bit more slowly than their deciduous counterparts. Because of this, you should check your bonsai every year to 18 months to ensure the roots are not completely rooted bound. Also, if you see your tree not growing as well as it once did, or not blooming and producing as it should, this is a good sign it needs repotting.
The best time to repot your bonsai is in the spring as it comes out of dormancy. Do this before bloom or new branch growth. Even though you can train your cotoneaster to acclimate to all year indoor living, it is best to provide proper seasonal temperature changes (more explained below) to ensure a full bloom each spring.
When you repot you can continue to use the same pot unless you are still working towards maturity and need a larger container. You also need to completely remix your soil substrate. Some rules to consider:
- Lift the entire plant from the pot and carefully tape soil from the rooms. Large, integrated pieces should not be removed.
- Take off about 60% of the root ball, leaving behind at least a third or more of the root. This will increase new root production which will be reflected in canopy growth.
- Mix a new substrate to plant in. Mix a bit slighting into the bottom of the container, place the root ball back on top, and gently work the soil back around the tree.
Shaping Your Cotoneaster
This shrub is a popular plant to use for cascading, slanting, exposed root, multi-trunk, and clump growth. It is a fun choice because of the many ways it grows allowing you to visualize and create your own intricate designs. It also thrives with pruning, which also results with many suckers making themselves present through the growing season. Part of the art form of bonsai is to not force a tree to grow a certain way, but recognize they natural shaping and support and influence this through pruning and wiring.
Prune your old wood in spring to influence new shoots, and start removing suckers as they become apparent. Without this vigilance, the trunk will not continue to thicken. Old wood will continue to bud back up, so to keep your canopy in check simply cut back to one or two leave off new shoots through early summer.
The leaves grow in a fishbone pattern as well, and you can use this to influence branch growth. To naturally guide the branches in the direction you want them to grow in, cut back to the leaves that are facing the direction you want the branch to grow in. Continue this practice as the tree grows to keep it well shaped.
Wiring your plant should take place in the spring before any blooms break. Gently use a soft copper, or stainless wire to nudge the branches in the direction you want them to grow in. Watch carefully to ensure the wires do not cut into the branches or are left for longer than they should and allow bark to thicken around them. Make sure to tie your wire to sturdy support to provide consistent pressure. If you have a particularly unyielding branch, do this little by little until you have the look you desire.
Seasonal Cotoneaster Care
As mentioned, cotoneaster can acclimate to indoor living, but it may end up in some undesired look. Evergreen leaves may fall if not allowed to go through a cold period. It is suggested that you allow your plant to experience a drop in temperatures for a few months each winter. Temperatures 45 degrees Fahrenheit or below are acceptable.
If you do place your plant outside for the winter, remember it is in a shallow container. Because of this, it is best not to expose it to below freezing temperature for too long at a time to keep from freezing the entirety of the root system.
How to Water Bonsai Trees
Cotoneaster actually thrives in cooler, dryer conditions, and so be sure to create a
careful watering schedule that allows your plant to dry out briefly between waterings. Remember, it will drain quickly through the provided substrate, and so a slow release watering may be best when you do water. You will need to water more often through the growing season opposed to winter.
Also adding a water tray beneath the tree helps raise the overall humidity surrounding the plant. This can help keep it from drying out too fast, as well as providing the moisture to the canopy that may be missing- especially in indoor environments.
Feeding Your Bonsai
Growing bonsai in such a small amount of soil requires that you have a regular fertilization schedule as well to ensure the roots can uptake the nutrients needed, as well as to replace those lost through the soil leech.
Starting every other week after you cotoneaster blooms you will want to provide a general fertilizer to your plant. Come late summer and fall, use a non-nitrogen option, and then continue this once a month through the winter. The hardiness of cotoneaster dictates that it doesn’t need quite as much care in this detail as many other types of plants, but if avoided will result in a plant that will not thrive or produce, and most likely eventually die.
Although there may be a lot of information provided above, you are interested in the art of bonsai, cotoneaster is an excellent choice to start with. Although it does require regular attention through the growing season due to its vigorous growth habit, it is a fairly forgiving, and easy plant to shape and showcase. Excellent for beginners, the biggest challenge you may have is deciding which kind to use. The thyme leaf cotoneaster bonsai, or rock spray bonsai, are particularly popular, as are any of the more showy varieties that have bright foliage and/or berries.
Be sure to always re-pot accordingly, provide light, water, and food as directed, and you should have a plant to enjoy for many years to come. If you have any questions about the species or above information, please let us know below. We’d also love to hear about your bonsai tree experiences! And, as always, please share!