Hello, 

I am growing one of my first Brazillian Rosewood bonsai, it is now about 6-7 months old and has grown quite tall. The top leaves have started falling off and I am wondering if I should be repotting it, or if it is too soon? The roots have begun growing through the bottom drain hole (see picture). I bought a small bonsai pot and some new soil, so I guess 2 questions:
1. Should I consider repotting it?
2. Is it too young to trim roots if I do repot / should I be pruning at all at such a young age?

Appreciate any insight!

For your Brazilian Rosewood bonsai, it sounds like you're at an important stage in its early growth. Since the roots are growing through the bottom drain hole, it is a sign that the bonsai may need more space. Repotting can help ensure the roots have enough room to continue developing. As long as the tree is healthy (despite the top leaves falling), repotting could benefit the plant. Ensure that when you repot, you are gentle with the roots, as they can be delicate.

Why do you think it needs re potting? There has to be a reason to do it, as this is just a seedling then I would have thought it does not need it possibly for a couple of years.

You are correct that young trees usually do not need repotting for several years, especially slow-growing trees like Brazilian rosewoods. However, if roots are growing through the drainage holes in the bottom, it is a sign that the tree may outgrow its current pot sooner than expected. If you see roots coming through the drainage holes, it is a sign that the tree could benefit from a little more space. Repotting to a slightly larger pot can give the tree enough room to continue to grow healthily without stressing the roots.

I am with Geoff. If you repot every time the roots grow out of the pot you will have a huge pot in a couple of years and creating a bonsai with nice nebari will be more difficult.

Uppotting approx once a year for maximum three times is a good guideline. After that first real repot including root pruning and back into the same pot.