Although Epsom salt is useful in certain situations, it’s not going to correct the problem you’re noticing. Epsom salts is a crystalline material and a source of magnesium sulfate. What you need is manganese sulfate! When soil conditions are too alkaline or too acidic, a manganese deficiency called “frizzle top” may occur in Sagos. This causes the newly emerged leaves to become yellowish-brown, frizzled and distorted.

To correct the condition, spray the leaves with manganese sulfate at the rate of 1 tsp. per gallon water monthly for 3 months. Also apply ½ to 2 pounds (depending on plant size) of manganese sulfate to the soil annually. 

Additional Resource 

http://collier.ifas.ufl.edu/CommHort/CommHortPubs/sagosMANGANESEdefic.pdf

http://hort.ufl.edu/shrubs/cycrev.pdf