Japanese Maple (Acer Palmatum)

Profile: Perhaps one of the most popular bonsai species, the Japanese maple is is vibrant, delicate and beautiful. Due to the popularity of the maple as an ornamental tree, several varieties are now available to be used as bonsai. The Japanese maple is native to China, Japan and Korea. You can find specimens in most garden centres ranging in size and variety. The Maple, although beautiful, has its own challenges when it comes to growing them as bonsai. The Maple has thin and delicate leaves which are prone to leaf burn from either the sun or harsh wind. Keeping them in a protected space will ensure that you have a healthy-looking bonsai. 

Tree Position: Keep this bonsai outside in a sheltered position and protected from strong winds. It may be displayed inside for up to 3 days at a time. When placed outside, place the bonsai where it will receive part shade. A great place for a maple is where it receives both morning and late afternoon sun, but not midday sun. Lastly, keep the maple where it will be protected from strong wind. The maple will withstand cold up to -10°C during winter dormancy.

Watering: The Maple loves frequent watering on hot days. Make sure that you're watering a little bit more when the leaves are opening during the warmth of Spring. Ensure that the soil is always damp but not soaking wet. How often you water your bonsai will depend on the weather and how deep your bonsai pot is. Use your finger to check how damp the soil is before watering. If it feels a little dry, then go ahead and water. As a general rule, water every day when it's hot, and water twice a week in colder winter months. Try not to follow a schedule when watering though, instead, check the soil to see if it is wet or dry. Wait a minute or two after watering, then water again. In Japanese bonsai culture they have a saying for this; 'For bonsai, it rains two times'.

Fertilizing: Feed your Maple fortnightly from spring through to autumn with a liquid fertilizer that has a balanced N.P.K ratio. Maples do benefit from a high nitrogen feed once in early spring after their leaves open fully. Always follow the directions on the fertilizer packet, and water the bonsai thoroughly before feeding to avoid root burn. Don't feed your bonsai during winter as the soil temperature isn't high enough to trigger the bonsai's response to uptake nutrients. Do not fertilize if the tree is weak or diseased. Lastly, do not fertilize newly re-potted trees for at least a few weeks. To maintain short internodes and smaller leaves, make sure that you're not using too much fertilizer or using too much fertilizer that is high in Nitrogen.

Re-potting: Re-pot this tree every year or two during late winter or early spring just before the buds break. The soil you use should be a well-drained soil. A basic mix consists of 1 part Dalton's coarse pumice and 1 part Dalton's potting mix. Ideally, you should use a 2 mm sieve to get most of the fine particles out. You can trim up to one-third of the roots before your bonsai goes back into the bonsai pot. Secure the tree to the pot with wire through the drainage holes. Maples will benefit from extra moisture in the soil (add more potting mix to achieve this). Place the bonsai in a sheltered and slightly shaded spot for a week or two after re-potting. At this crucial stage, we want to shelter the bonsai from the hot sun, heavy rain, frost, snow, and wind. Lastly, be careful to not over-water your bonsai after re-potting. 

Trimming: During spring and summer, your bonsai will be in full growth. Trimming is done to keep unwanted growth in check, direct growth, and to develop ramified foliage. Throughout the growing season, cut back stems to a maximum of 1 or 2 leaves. For example, if a stem has elongated too far (say it has 10 leaves), you can cut this back. Leave a minimum of 1 or 2 though. Doing this will result in dense growth. When making a cut, use sharp scissors and cut on a 45-degree angle. Aim to cut right above a leaf node. Before trimming spindly growth, think to yourself, will this stem grow into a branch that I may find useful? When your bonsai takes off in spring or mid-spring, allow the tree to grow so it can gain its strength. After a month or so of active growth, you can then trim your bonsai into shape. 

To achieve smaller leaves on the maple, one technique you can implement is defoliation. This involves plucking all the leaves off the tree in mid-summer (yes, you heard correctly!). Doing this will also result in better ramification and autumn leaf color. However, defoliation should only be carried out on very vigorous bonsai, and should never be done two consecutive years in a row or in the same year as re-potting. It should also be mentioned that some varieties tolerate being defoliated more than others (generally green-leaved varieties over red-leaved varieties). This could be the case because the green varieties of maple have more chlorophyll in their leaves and are therefore more vigorous growers.

Pruning: This involves cutting larger branches and requires you to have a concave or branch cutter ( if you have neither, a sharp pair of secateurs will do) The best time to make strategic pruning cuts on a Maple is from mid-summer through to Autumn. Don't remove more than one-third of the tree's foliage when pruning unless the Maple was vigorous in its last growing season. The overall shape you are trying to achieve is a triangular silhouette where the top of the tree is highest. Unsightly branches should also be removed. This includes dead branches, branches that cross over each other, and branches that hide the bottom third of the trunk. Create space so light and air can enter the tree. With the maple, it is a good idea to seal wounds, but it isn't compulsory. You can seal wounds with tree cut paste or petroleum jelly if you have some of that. 

Wiring: Wire the Maple at any time of the year. Although there are pro's and con's to wiring the maple at various stages. Having no leaves makes it easier to wire your bonsai, so that would mean wiring in early Spring before the buds break, in Autumn, after leaves have fallen, and after defoliation. Just be careful with your Spring wiring, as new buds can easily be scraped off if you're not careful. Also, in spring, growth will be taking off, which is a good and bad thing. Your branches will set in place fast, but the branches you've wired might get too thick too fast and damage the branch. Check the wire often to avoid this. Autumn wiring has its disadvantages too, as the wired branch won't set in place properly until growth starts in Spring. This means that you'll need to protect the tree through winter, ensuring that no overly cold weather damages the supple branch.

Larger branches will take longer to set than smaller branches. Maple branches (when relatively small) set in place after a very short period of time during the growing season. Ensure you are using the right thickness of wire for each branch. A general rule of thumb is that you should apply wire that is roughly 1/3 the thickness of the branch you are planning to wire. When wiring, try to turn any straight growth into curves (this includes the trunk and branches. Old trees tend to have twisted trunks and branches, so we copy nature here.

Pests and diseases: Maples can be affected by aphids, scale, and various viruses and fungal diseases. Yellowing leaves can signify the beginning of root rot or nutrient deficiency. Check the soil first and then look at correcting the deficiency by researching the discolouration or mutation of the leaf. It should be noted that Maples will often have a few yellow leaves during the growing season in response to dealing with excess nutrients. Maples are also deciduous trees which means that they lose their leaves every year in a fantastic show. 

Bonsai Difficulty: ★★★☆☆