Ficus salicifolia is one of the few Ficus that I like to cultivate as bonsai. They are easy to care for and manage, and given the proper conditions are rampant growers.
My favorite salicifolia at the moment is a hapless tree that I purchased for a bargain from a local highway robber. An uneducated highway robber, because the tree had dropped all its leaves and the owner considered it dead. A scratch of the cambium revealed otherwise, and now it resides in my collection. Originally it was shohin sized, but no thought had been given to soil conditions, design, etc., so I decapped it about three inches above the soil leaving a pencil thick low branch to take over as a leader. It should make a great mame sized bonsai, and is well on the way to meeting my design goals. Here are some observations about how to keep it happy:
Soil-- I have been using a mostly inorganic soil, the mixture being 4 parts sifted Terragreen to 1 part sifted Oak Leaf mold. This has resulted in a profusion of fine feeder roots sans those annoying 'carroty' type roots which often preclude the use of a suitable bonsai pot. Once those heavy roots were initially pruned they have not returned. There has been a corresponding breaking of buds along the trunk, which is a chunky two and a half inches at the base. I think if you use a freely draining soil like this one you will say good-bye to yellowing leaves. Also, bear in mind that fresh growth is a very pale green with some yellow and red (sometimes). This will darken to bright green later when the leaf sets.
Light-- Obviously, more is better. These are tropical trees, and length of daylight is just as important as intensity. Salicifolia creates long, narrow lancelet leaves, so keeping daylight at a maximum will help keep leaves in scale with the design. I have been told that Ficus narifolia is a small leafed cultivar of salicifolia. I would suggest extending, through the use of artificial light, the tree's 'day' to 16 hours. Bottom heat is also welcomed.
