TreeView Binding List<String> - treeview

Question

I can't seem to figure out how to get the TreeView to display a List
I checked SO, but can't sem to find the same scenario the leafs always seem to be objects and not simple strings.
I can't figure out the correct combination of HierarchicalDataTemplate and DataTemplate to get it to work. Using the following Object. The binding happens I just only see the first level and not the leaves.
public class Trunk
{
public Trunk(string tn)
{
TrunkName = tn;
Branches = new List<Branch>();
}
public List<Branch> Branches { get; set; }
public string TrunkName { get; set; }
}
public class Branch
{
public Branch(string bn)
{
BranchName = bn;
Leaves = new List<string>();
}
public List<string> Leaves { get; set; }
public string BranchName { get; set; }
}
Tree = new Trunk("Root")
{
Branches =
{
new Branch("Branch1"){Leaves = {"Leaf1","Leaf2"}},
new Branch("Branch2"){Leaves = {"Leaf3","Leaf4"}}
}
};
And the following Template
<TreeView ItemsSource="{Binding Trees}" >
<TreeView.ItemTemplate>
<HierarchicalDataTemplate ItemsSource="{Binding Branches}">
<TextBlock Text="{Binding Path=TrunkName}" />
<HierarchicalDataTemplate.ItemTemplate >
<DataTemplate>
<TextBlock Text="{Binding BranchName}"/>
</DataTemplate>
</HierarchicalDataTemplate.ItemTemplate>
</HierarchicalDataTemplate>
</TreeView.ItemTemplate>
</TreeView>
EDIT:
Of course after spending days trying to figure out what wasn't clicking. I figured it out after posting for help.
PS the TreeView ItemsSource is set from the ViewModel bound to the Window DataContext.
<TreeView ItemsSource="{Binding Trees}" >
<TreeView.ItemTemplate>
<HierarchicalDataTemplate ItemsSource="{Binding Branches}">
<TextBlock Text="{Binding Path=TrunkName}" />
<HierarchicalDataTemplate.ItemTemplate >
<HierarchicalDataTemplate ItemsSource="{Binding Leaves}">
<TextBlock Text="{Binding BranchName}"/>
<HierarchicalDataTemplate.ItemTemplate >
<DataTemplate>
<TextBlock Text="{Binding }"/>
</DataTemplate>
</HierarchicalDataTemplate.ItemTemplate>
</HierarchicalDataTemplate>
</HierarchicalDataTemplate.ItemTemplate>
</HierarchicalDataTemplate>
</TreeView.ItemTemplate>
</TreeView>