QuestionsHow to growTrees and ShrubsWateringtrees 0 Vote Up Vote Down louise lally asked 14 years ago Im just wondering about my silver birch and acer drummondi trees. they leafed well but now have started to lose some leaves and some have gone brown. 1 Answers 0 Vote Up Vote Down Gerry Daly Staff answered 7 years ago Young trees can take a while to root out into surrounding soil. Water every week or ten days about 10 to 20 litres.