Split neotree frame horizontally

[qohelet]

I love to use neotree but most of the time I only require the handfull of files which are located in the upper third of the frame.

To make use of the unused space below I'd like to split the frame horizontally and show a list of the currently opened buffers.
Yet the neotree-frame refuses to be split and I can't figure out how.

 Status: Installed in ‘neotree-20181121.2026/’ (unsigned). Delete
Version: 20181121.2026
Summary: A tree plugin like NerdTree for Vim
Requires: cl-lib-0.5
Homepage: https://github.com/jaypei/emacs-neotree
Other versions: 20181121.2026 (melpa).

I was looking around already but couldn't find any solution that worked. Using GNU Emacs 26.1 (build 2, x86_64-pc-linux-gnu, GTK+ Version 3.22.30)
of 2018-05-29