The Hawaiian umbrella bonsai (Schefflera arboricola) is a tropical tree native to Australia. This tree can also commonly be found in Southeast Asia.
This bonsai is an evergreen shrub in the wild with thin trunks. This bonsai doesn’t have many ramifications, but its popularity and the characteristic feature come from its leaves. The leaves are arranged radially in a compound fashion on long petioles.
Hawaiian umbrella can also be found in a dwarf version which makes better bonsai. These trees also don’t produce hardwood or any rough bark making them one of the softer bonsai species out there. For this reason, it can be quite difficult to train this bonsai to display some ramifications. It is, however, a great specimen for a rock bonsai due to its tendency to develop mangrove-like roots.
If you are new to bonsai keeping and don’t feel comfortable enough to attempt wiring, this bonsai may be perfect for you. It is often quite simple to prune this bonsai into a simple, but stunning shape without the use of wires.
Wiring this tree can be extremely tricky and should never be attempted by beginners.
Care Guidelines For Hawaiian Umbrella Bonsai
Caring for a Hawaiian umbrella bonsai is fairly simple. Here are a few guidelines to get you on track with your tree’s daily care.
Hawaiian bonsai are excellent trees to keep indoors all year round. These trees tolerate low light conditions with very little humidity but they do grow better in bright light. When grown in strong light conditions, the leaves will be smaller and grow in a more compact fashion which is exactly what is desired by bonsai growers.
Due to being able to cope with low humidity, it is possible to bring your tree into your home in winter. It won’t be negatively affected by the central heating system or any other heat source in your home.
In fact, it even prefers being near a heat source.
The ideal temperature for this tree is between 65-72° Fahrenheit (18-22°C) but it can tolerate temperatures as low as 50° Fahrenheit (10°C). Make sure to never expose it to a temperature lower than 50° Fahrenheit (10°C) if you want your tree to stay alive.
If you live in an area where the temperature outside often rises above 59° Fahrenheit (15°C) your umbrella bonsai can enjoy some full sun outside. Just make sure to introduce it gradually to sunshine to avoid leave burn.
Watering a hawaiian umbrella bonsai is an art in itself.
The trick is to water as little as possible without letting the soil dry out completely to maintain healthy roots while stimulating the growth of small leaves and short internodes.
It is very important to keep the soil moist since umbrella bonsai don’t tolerate dry soil.
If your plant is kept in full sun or near a heat source, you will need to check it more frequently to make sure the soil never dries out completely. When you water, make sure to give enough water that it freely drains out of the bottom of your pot. Doing this will prevent salt build-up in your soil that will negatively affect your plant.
If you want to encourage air roots, a humidity tray is a great idea.
Simply fill a shallow tray with pebbles and water. Place your pot on top of the pebbles out of reach of the water. As the water evaporates, it will create a humid bubble around your plant.
This is a great way to increase humidity without the risk of root rot due to overwatering your plant.
Soil And Fertilizing
Bonsai are kept in shallow pots with very little soil. The Hawaiian umbrella bonsai is no exception.
For this reason, you will need to fertilize your tree frequently to encourage healthy growth.
There are two forms of fertilizer available for use on bonsai. If you want to be more involved and prefer to fuss over your tree, then liquid fertilizer is a great choice. Liquid fertilizer needs to be applied weekly throughout the growing season. In the three months of winter, however, you can reduce fertilizing to once a month to give your tree time to rest.
If you prefer to be less involved, solid fertilizer might work better for you.
Solid fertilizer needs to be applied once a month during the growing season.
During the three months of winter, you can skip fertilizing completely until spring comes around again.
No matter the form of fertilizer you use, make sure to either water your plant immediately after fertilizing or just before you apply it. This is especially important if you’re using liquid fertilizer. Failing to water your plant immediately will lead to root damage due to the concentration of salts in the fertilizer.
It is also recommended to only use half the recommended strength of fertilizer prescribed on the packet. Bonsai are meant to grow slowly and stay small so over-fertilizing will have a negative effect on the growth rate of your tree.
For this specific bonsai, it is better to use a low nitrogen fertilizer. Using a fertilizer with lots of nitrogen will encourage the leaves to grow bigger at the expense of root and bark development.
Hawaiian umbrella bonsai are very easy to prune. Simply remove the growth at the end of a shoot as soon as it reached the desired length based on your style and design. It is also possible to remove any large leaves to encourage smaller leaf growth.
If the overall appearance of your tree’s leaves is too large, increase the amount of light your tree receives to encourage smaller, more compact leave growth.
When removing large leaves, you can leave the leaf stalks in place.
As they dry out, they will fall off on their own without any damage to your bonsai.
If you have enough humidity, your bonsai will develop something called air roots. These roots are what give this tree its mangrove-like appearance.
For this reason, these trees are often trained to grow over a rock.
Styling umbrella bonsai into traditional Japanese styles is not encouraged for this tree. It is usually kept as an informal upright or encouraged to grow in small clumps with many trunks.
Hawaiian umbrella bonsai needs to be repotted every two years. The best time to repot this bonsai is in spring. Remove all large leaves before you start the repotting process to reduce stress on your tree. Once that’s done, you can take your tree out of its current pot.
It is very important to be gentle when repotting this bonsai. It has large fleshy roots that break easily. This tree does, however, respond well to heavy root pruning.
You can stick to a standard soil mix for this tree. It has no real special requirements as long as it has soil that drains well while still retaining moisture to prevent the root ball from drying out.
The easiest way to propagate a Hawaiian umbrella tree is to grow it from seed or take cuttings. Seeds will sprout readily if planted in spring. Cuttings are best taken during the growing season and will grow roots readily in a glass of water, or even when placed directly in the soil.
The seeds grow best when sowed in bonsai soil mix or in a mixture of sand, peat moss, and loam mixed in equal amounts. Make sure to cover the seeds with a thin layer of your soil mixture or some sand. Keep them at a temperature between 68 to 86° Fahrenheit (20-30°C) for the best results.
Potential Pests And Diseases
This tree is unfortunately quite susceptible to pests and diseases if not cared for properly. The best way to prevent any problems is to keep your tree in a healthy environment with healthy soil. You will need to wipe the leaves to keep them dust-free and do weekly inspections to pick up on any problems before they get worse.
Also, make sure your tree is draining properly after every watering. Soggy soil is a sure recipe for developing root rot and fungal diseases. Some of the most common insects to look out for are spider mites and scale. These pests can be treated with insecticides or homemade solutions such as rubbing alcohol or neem oil.
Wiring Your Bonsai
Hawaiian umbrella bonsai are not easy to train.
It is possible to wire it, but this feat should only be attempted by experienced bonsai keepers.
The best time to wire this tree is while the shoots are young and green. They are less likely to break at this stage. Once they harden, the branches become very fragile and tend to break during wiring.
The best way to train umbrella bonsai is by doing pruning. Once the stalks reach the desired length, simply cut the tip off. You should keep up with regular pruning during the growing season to keep your tree in shape.