Placing green leaves on graves was mentioned in one of the Prophet's hadiths and there is no prohibition, and so is the case for pouring water,on graves. But the problem is that nowadays, flowers are very expensive and purchasing them is a waste of money, and it is not beneficial for the deceased. With that amount of money, it is better to benefit the deceased by giving charity on his behalf. As for placing green leaves and
pouring water on graves, it is not costly..

لا يوجد نهي وورد أنه وضع فرع شجر أخضر ورش بعض الماء، لكن المشكلة أن الورود أصبحت غالية الثمن ويسرف الناس فيها ولا فائدة من ورائها للميت، فَلَو تصدق بثمنها بنية المتوفى لكان خيرا له، فوضع فرع أخضر ورش الماء لم يكن يلف شيئا