What is wrong with my bonsai tree?
Your tree I am assuming is better known as a Trident Maple and to be honest it is not an indoor tree. Yes, they need winter protection from frosts etc. but are best kept outside. Yes, your tree needs water but dont over water, the soil (compost) should be damp but never sodden (tree’s can drown). This means it may not be necessary to water every day. The leaves growing back larger and darker is because it will always try and revert back, remember in open ground it would grow into a full sized tree. Best advice is to place it outside in a sheltered spot, not necessarily in full sun, water when required and dont start to feed again until tree has fully recovered and the leaves have stopped falling. Invest in a Bonsai book, good ones are by Peter Chan, Harry Tomlinson, Colin Lewis. There are many web sites that are worth a look. There are methods that will reduce the leaves and return the colour again, dont despair, your best friend is patience.
