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Acer buergerianum
trident maple
| The trident maple is a very popular species for bonsai, due to its small, three-lobed leaves, a readily-thickening trunk, and thick, gnarly roots which adapt well to root-over-rock style. A small tree, the trident maple usually grows only to 20 ft. in nature.
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| | Lighting: | Tomlinson disagrees with Simon and Schuster: he believes this maple needs full sun; S&S recommends partial shade.This may have a lot to do with the environment of the tree in question; tridents in climates with extreme sunlight require shade. | | Temperature: | Although hardy in zones 5-8, the trident maple's roots have a high moisture content, and are susceptible to frostdamage. This is a potentially fatal problem expereinced by members of the list/RAB and warned against in almost every book. Tomlinson goes so far as to suggest the substitution of Acer ginnala, the Amur maple, in colder areas. At the very least, this tree should be carefully winter protected. | | Watering: | Moderately in summer, easing off in winter. One poster remarked that tridents seem to get along fine in a climate with much rain. | | Feeding: | Tomlinson, as he usually does, suggests an aggressive feeding schedule: once weekly for the first month after leaves appear, then every two weeks during growth. S&S recommends feeding every three weeks during growth, with an interval in midsummer. I've used the more conservative schedule with my tree and have been happy with its growth, but find it entirely possible that more frequent feeding would improve the vigor of the tree. More frequent feeding, however, requires increased vigilance in pinching back. If a liquid fertilizer is used, it should not be sprayed on the leaves, as this may result in leaf burn. | | Repotting: | In spring, before bud burst. Roots grow very quickly,so annual repotting may be necessary for young trees; older trees tend to need repotting every 2-3 years. If root die-back has occured during the winter, trim off old root matter to allow room for new growth. Tomlinson recommends a fast-draining soil mix; I've had success with a standard bonsai soil. | | Styling: | Pinch back new growth to the first two leaves. The tree may be wired at any time during growth, but the branches are somewhat brittle and it is also wise to provide some protection for the bark. The tree, given ample pot space, will grow rapidly, so it is essential to continually check the wire to avoid scarring. Leaf pruning can be carried out in midsummer to miniaturize foliage. Make certain that the tree is healthy and vigorous before leaf pruning. Total leaf pruning should not be carried out annually, as the tree needs a year to restore its stores of energy. I've been told that it's safer to leaf prune gradually, removing only 1/3 to 1/2 of the tree's largest leaves at a time. The trident's leaves reduce readily, but it is more difficult to get short internodes and finely ramified branches. For the more advanced/courageous among us, Brent Walston suggests:For smaller pieces, in one gallon training pots, I let them grow wild for 2 or 3 years until the roots completely fill the pot and there is a noticeable decline in vigor. Theinternodes shorten and the leaves get smaller. It is at this point that I do major pruning shortening them to under a foot. The depleted state of the roots due to the rootbound conditions prevents them from forming the typical coarse growth that usually results following such a pruning. Performing this operation in summer will have an even more dramatic effect, since in essence it is a radical (very radical) defoliation. Root pruning and repotting can take place at the same time. As Michael would say, these are not procedures for beginners. Once there are potted up and the final branches are selected several defoliations a season will result in the short internodes and small leaves so desired. | | Propagation: | Trident maple can be grown from seed, air-layered, or grown from both hardwood and softwood cuttings. Tomlinson says that even wrist thick cuttings may take, and one instance of a six-inch (!) cutting being rooted successfully has been reported. Best results are achieved taking cuttings in late winter-early spring for hardwood and midsummer for softwood. Seeds require a 24 hour hot water soak, then cold-moist pretreatment for three months. Seeds need to be stored refrigerated, which will start the cold-treatment process. Seeds kept in dry storage are tough to activate, resulting in a poor percentage of germination. If you cannot collect your own seed, it seems that purchasing fresh, properly stored seed from a reputable dealer is essential. | | Pests: | As with other maples, tridents seem to be sensitive to leaf burn. Tridents are also vulnerable to caterpillar attack. |
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