Step 1
Plant the first tree en draw through this tree two lines at random. On
these lines the other trees will be planted.
Step 2
Now draw a random line through the other two lines. At the crossings you plant a tree.
Step 3
Draw a random line that goes through the tree other lines. Again, plant a tree at the crossings.
Step 4
Draw a random line that goes throug 4 lines. At the 4 crossings you again place a tree.

In this way you will always end up with a garden in which 10 trees are in 5 rows of 4 trees each.
The garden of neighbor Sym would look as follows. He probably is jewish because his trees are planted as a star of David.