We are having trouble with California fan palms. We planted two (about 6 feet tall) in a planter, along with a couple of other palm breeds (Sylvester Dates and Windmill Fans). The others look great, but the California fan palms are getting more yellow every day. The bottom fronds are sagging, and even the top ones are starting to get yellowish and a little crinkly/brittle. Is it possible that we are overwatering? Once we noticed the problem about 10 days ago, we started watering the hell out of them, thoroughly soaking the soil at least 2 times a day. But they still seem to be getting worse. Help, please!