One of the more hardy Maple Species is the Acer Buergerianum More Commonly Known As The Trident Maple. The Trident Maple makes an excellent Bonsai Both as a larger tree or a shohin tree. If you live in either An arid hot area with high temps during summer you will know the pain of trying to keep a Japanese maple looking nice, But if you have a trident maple this is much easier to achieve. The Trident Maple is also a lot more resistant to frost then the Japanese Maple.
So what are the guidelines for this species? ( remember to adjust slightly for your environment )
Watering: Being a Deciduous Species the Trident Maple has a high water mobility during its growing season through spring to move resources and also through summer. In higher temperatures the tree will move lots of water to cool the trunk and foliage. This begins to slow down during the autumn months and really slows up during the winter period so you need to water accordingly.
During spring you will be watering at least once a day and during summer 2 - 3 times a day ( depending on your environment and soil substrate ). During autumn you really have to watch the soil to judge the watering frequency as you will see the tree stay wet for longer periods and as you approach winter you will notice the tree staying wet for days. ( i have heard of people in Europe only watering 2 - 3 times during the whole winter period ).
If you live in an extremely cold environment it is advised to keep the soil closer to the dry side to avoid frost damage to the root system.
Positioning: The Trident Maple Can handle full sun if you are around to keep up with the watering schedule and you have a good substrate. If you are not around a lot during the hotter months then place the tree under some light shade or a shade structure if you have one. Places that have lots of hot dry wind need to be mindful of watering as well as too much hot dry wind can dry the leaves out very fast. You can combat this by placing your Trident Maple between 2 larger trees to provide some shade and a wind block. Try to avoid placing your tree near metal fencing as this radiates heat.
If you have cold winters under around 0c i would suggest some winter protection to avoid frost damage to the roots, Given the tree does not move much water during winter if the soil is wet and freezes you can damage your root system.
Pruning: On a developing tree you will want to let the tree grow vigorously to gain thickness then cut back hard and let grow again to create taper. On a tree in refinement though it is a much more delicate balance when it comes to pruning. Generally in spring we will let the tree shoot out at least 6 - 8 sets of leaves before cutting that shoot back to 2 sets of leaves. If your tree does not shoot out at least 6 - 8 sets of leaves per shoot then that could be a sign your tree is weak and you might want to hold off pruning for a while, by leaving foliage on the tree you will help it gain some strength and vigour. The reason we allow the tree to extend to 6 - 8 sets before cutting back is because the tree is spending energy to grow during spring, it will re gain that energy through the new shoots it has put out, if you cut those shoots off before they harden off and have time to give the tree back energy then you are draining your tree of energy. After a year or 2 of this you may start to lose branches or worse your entire tree. You want to allow the leaves time to harden off a photosynthesis before doing any pruning. To avoid long internodes hold off on feeding until the first flush hardens off.
During summer if the canopy of the tree gets too full you can either cut the outer leaves in half or perform partial defoliation of the outer leaves to allow sun and air flow in to the interior branches. keep in mind though in hot areas that you want to keep spme leaves on the tree to allow the tree to move water and transpire to cool it self off. if your tree happens to drop all its leaves during summer for one reason or another keep it in a cool shady spot until it shoots a second flush of growth and allow it to harden off. if your tree has no leaves and is out in the heat it can suffer from trunk burn.
Fertilisation: Once again in Development we want to feed feed feed, High in nitrogen to get as much growth as possible. In refinement we need to be much more calculated. Once we reach a point of creating fine ramified branches we want to be using a fertiliser that has a nitrogen content lower then 10. We also want to hold off on fertilising in spring until the first flush hardens off and we cut back to our 2 shoots. Keep in mind though that organic fertiliser does take a few weeks to start breaking down before it feeds the tree so you can apply a week or 2 before you think you will need it. Through summer and autumn you want to keep applying your fertiliser around every 4 weeks at a mid to low strength.
Repotting: Trident Maple can be re potted every year but i would wait at least 2 years unless your soil is having trouble taking on water. Root growth in Trident Maples is very strong. The timing will be around the end of winter sometime, you need to watch the tree, as the buds begin to swell you can re pot but if the buds fully burst you have missed your window. Trident Maples root systems can be cut back pretty aggressively which makes them a great contender for shohin Bonsai and for planting them in a shallow pot. Make sure you pay special attention to the roots close to the surface and lay them out in a radial pattern to create a nice nebari. After re potting protect the tree in a shady area protected from wind for around 2 weeks.
Substrate: For a tree in development have your tree in an organic mix that is well graining. For a tree in refinement you can either plant in 100% akadama or mix in some pumice if you live in either a really humid area or an area that rains alot. Keep in mind if you plant in 100% akadama you will need to re pot every 2 years so don't miss your re potting window, pay close attention. 100% akadama is only good for Tridents in hotter areas that have a lower humidity though, if this is not you then i suggest adding in some pumice starting at around 20% and increasing for area with higher rain fall through out the year. It is also a good idea to have more pumice in your mix if you live in a environment that experiences frost during winter as this can cause softer akadama to break down quicker.
Propagation: Growing from seed ( plant in autumn, protect during winter )
Soft Wood Cuttings ( Mid Summer )
Hard Wood Cuttings ( Late Winter Early Spring )
Air Layer ( During Spring )
I hope this information gives you a nice solid base to start from with Trident Maple, One last tip is that trident maple are a great candidate for root over rock plantings so have some fun with that style. Other then that they a suitable for Informal Upright, Formal Up right and slanting styles.
Until Next Time, Enjoy Your Bonsai Journey.
