Didier in La Chapelle sur Loire, is having problems with a Polyscias, a magnificent indoor plant whose leaves are turning yellow and falling off. Here is the answer of Maryse Friot, President of the Horticultural Society of Touraine
the Polyscias is a green indoor plant with decorative foliage native to New Zealand requiring heat and humidity (tropical zone). The plant, due to its origin, is capable of losing its leaves to protect itself and put itself in a state of vegetative dormancy. This is the case during a lack of light, if the temperature is below 18°, during a lack or excess of water.
This plant therefore requires: light, a temperature above 18°C and constant humidity without excess. It is a cool but not flooded soil plant.
I think your Polyscias has been over-watered this summer. Root asphyxia caused widespread yellowing of the leaves, which became soft and gradually fell off.
A lack of watering would have caused a drying out starting with the tip of the foliage then a hardening of the leaves and a beige or brown color for all the leaves.
In the case of an excess or a lack of water, the foliage falls because the plant protects itself.
– If there is excess water, the stems soften, the roots rot and the plant dies.
– If there is a lack of water, the stems lose their flexibility, they break easily, the roots are still healthy. You have to soak the root ball so that it fills up with water. The plant may be able to survive.
In any case, before condemning the plant, check the condition of the stems (soft or still hard), unpot it to check the roots. If they’re rotten, there’s no hope, but if they’re dry, you can still save her!