Posted: 30/09/2014 at 08:16
It's the calcium content in tap water that is bad for ericaceous plants, not the other chemcals so leaving it to stand will not help. However you can buy sequestered iron in good garden centres and add that to water to help plants take up the iron they need.
Camellias, rhodos and azaleas need plentiful water in late summer and autumn to ripen their flower buds for spring. Soak the root ball in water to make it easier to pull out all those weeds then pot up in a bigger pot, if possible, and use good ericaceous compost. Put out a container to collect rain water for it if you can.
Yellow leaves (chlorosis) on green plants can be caused by lack of nutrients, lack of iron and also lack of magnesium. If they persist after all the TLC, use a solution of 1 tbs of Epsom salts dissolved in a gallon of water and spray it over the foliage next spring. Repeat as necessary with this and any other plant with similar problems.