My Japanese maple looks like growing too heavy on the left size. Is that ok to remove the lowest branch out so to make it grow like a weeping canopy?
You may certainly do so, although many people prefer a more waterfall style of growth in Japanese maples. Not knowing which cultivar this is, it’s hard to say what it’s natural growth habit may be.
You may like to review our Gardening Guide on Japanese Maples, here.
And this article provides an excellent overview on pruning them.