by Tom Kruegl
The tree, a Ficus salicaria/salicifolia Willow Leaf Fig, was adopted from Carl Rosner in the winter of 2009 and brought to my home in May. It was vigorous and in excellent shape.
It lived happily outdoors in full sun all summer. Once temperatures were consistently dropping into the 50's, I moved it inside for the winter. It was sitting on a propagation mat in a west facing window under a 48", 5 bulb T-5 florescent light along with my other tropicals.
In late August, the crown was thinned lightly to allow in more light and air circulation but I don't believe this process had anything to do with the problem about which I am writing.
Soon after bringing the tree inside, I began noticing a few yellowing leaves.
Some foliage loss is normal indoors in the fall
I assumed that this was due to the stress of moving it into the house. I continued to water the tree when it started to dry out using the bamboo stick with which I monitored the soil. The stick was located at the edge of the pot. When the stick was dry to within the last inch, the tree was thoroughly watered or so I thought. Soon I discovered a fallen leaf here and there. I continued to carefully water and every once in a while I would put the tree in the bathtub and thoroughly water the crown and substrate. The soil was a mix of 1/3 turface, 1/3 lava and 1/3 sifted pine bark. Originally, potted about March of 2009, it was a nice open soil with a bit of moisture retention.
At one point, I thought I had the problem under control. This was after soaking the pot in a tub of warm water. The yellowing and dropping of leaves temporarily slowed and new red leaf buds seemed to be swelling. I then resumed my normal watering routine.
Suddenly, 90% of leaves were yellowed, and seemingly overnight they all dropped!
Unhealthy and showing nearly all foliage dropping off
After studying about emergency repotting in Jerry Meislik's book "Ficus: The Exotic Bonsai", I decided it was time to act. I carefully lifted the tree out of its pot. I found long large roots circling the rootball at its edge. They had very few fine root hairs at their ends. I teased them out and removed them. Then I combed out the fine roots within the rest of the rootball. During repotting, I found the fine feeder roots in dry, caked substrate at the top of the root pad. The bottom was sparsely populated by long, thin roots which escaped from the hard dry substrate. I loosened the underside and removed as much of the old soil as possible. The surface had been top dressed with plain lava for aesthetic reasons.
The tree was then put back in the same pot using pure lava. The lava was carefully and thoroughly worked into the remaining root pad. The tree was watered from above with warm water until the excess water ran clear of lava dust and placed back on the warming mat. At this point there were few leaves remaining. However, at the end of each branch there were living red leaf buds. There were a few fine desiccated and dead twigs which were removed.
Reconstructing the problem I think that when I watered, the water seemed to penetrate properly, but in reality it went through the lava, hit the hard compacted, dry soil beneath and ran off and down the sides of the pot without wetting the bulk of the soil and roots. The soil was never being totally moistened except when I put the pot in the tub and thoroughly drenched the soil mass.
In about 3 days the leaf buds began to swell. I was encouraged. Now, two weeks later, the upper part of the tree has fresh new bronze colored leaves. The buds on the lower branches are also beginning to show some life although I think it will take some time and a lot of careful attention for the tree to recover fully.
New sprouts in bronze coloration after repotting into good soil
In summary, normal watering, and checking with the bamboo pick was not reliable as the pick indicated the water situation only in the small area where the pick was inserted and was not indicative of the whole soil mass.