Acer x conspicum Silver Cardinal

this maple in my garden s fast growing around 35-40 cm/year in spring is stunning!!wonderful!!in june many leaves burned in summer remain only a few number of leaves ,maple open many reserve buds and re-sprout again but new leaves down before autumn  .i put pine bark mature fertilize of cow .general conditions remain no well..this year 2014 halleluja!! one cold spring and one cold summer ,and leaves reamain on the branch.the expo is full sun