garden tree

So I have been fortunate to know someone that said I could have this tree (height: around 50in/1.3 meters). I won't need to immediately remove it, I can leave it in its natural habitat for quite some time. What are measurements I can take while this tree grows further, to add to its aspect as a...

So as title says, I'm looking for a tree for the bottom left area of my garden. Sorry think I have asked this somewhere before, but making a thread so I can find easily! Parts of this area get boggy so I'm happy to look into drainage if needed? Clay soil, south west facing, gets some PM shade...