Here is a brief photographic history of a Trident maple over rock (Acer buergarianum). It was originally bought as a training piece in 1996 from Ken Leaver of Windybank Bonsai and it is a combination of 5 trees fused together over the rock. The leaves as they flush in spring all flush at different times which originally caused some concern when the owner first bought the tree. The rock forms a cave also which creates an attractive scene and the tree comes into its element in autumn with the different trees displays variations in autumn colour and the timing of the colour as the back section that leafs up first also goes into autumn colour first. The pot was damaged that it was originally in which was made by the owner and now the tree is in a Walsall Studio Ceramics pot commissioned through Dave Jones.

Trident Maples are from the Aceraceae family and their Latin name is Acer buergerianum. They are deciduous and grow in a naturally upright form. They make a great bonsai tree as they have a smaller leaf than many maples and have beautiful peeling bark and have brilliant autumn colour with oranges, reds and yellows. They have a tri-lobed leaf which is glossy green above and slightly paler on the underside. They have small yellow flowers in the spring and wing shaped seeds in the autumn.

They can be positioned in full sun if they are kept in a deep bonsai pot but need to be shielded from the hot sun or wind to avoid leaf scorch or if in a shallow bonsai pot as they will dry out too quickly. They also should be protected from frosts as they are not fully frost hardy as a bonsai. They need like most bonsai to be watered regularly and not allowed to fully dry out and planted in a free draining soil mix. They are usually re-potted annually in early spring before the buds open and feed after the first flush of leaves appear. They tolerate heavy root pruning and develop a good root pad through training fairly quickly.

They grow vigorously and trimming back of the new shoots to one to two sets of leaves throughout the growing season will aid in ramifying the growth subject to the state of the development of the tree as a bonsai. They tolerate leaf cutting and defoliation but again subject to the vigour of the bonsai tree developmental stage, this should only be done infrequently. Trident maples are renowned for their growth and the majority of the growth tends to be focused on the trunk thickness. They easily develop thick impressive trunks and also fused together well when one or more trunks and placed against each other. They can be propagated from seed or from thick cuttings and they also air layer well. As bonsai they make excellent root over rock styles due to the fast trunk thickening as well as good formal and informal uprights.

There are a few cultivars of Acer buergerianum which include:

  • Acer buergerianum ‘Goshiki kaede’ (Pink and green variegated)
  • Acer buergerianum “Kifu Nishiki’ (roundish nearly un-lobed leaves)
  • Acer buergerianum ‘Mino-yatsubusa’ (slower growing more dense form with more slender lobes of the leaves)
  • Acer buergerianum ‘Mitsubato kaede’ (Cork barked)
  • Acer buergerianum ‘Miyasama kaede yatsubusa’ (smaller leafed form)
  • Acer buergerianum ‘Naruto’ (rolled leaf edges)