I love Redon’s artwork, both early and late. I feel that they are very emotive, he is able to take mere ideas and turn them into expressive works of art.
Redon’s earlier work consisted of black and white drawings, known as his “noir” work, as he describes it. These pieces are very detailed and realistic (e.g. Two trees) . However he did not feel that these pieces were emotive enough and so turned to more abstract and dream inspired work. (e.g. The crying spider)
While sticking to his new style, he stared using more and more colour in his work. He would start with a black and white under drawing and then go over in colour.
He used a verity of mediums and would layer them in order to create his desired effect. He was very experimental with his techniques. I too enjoy experimenting with mediums and techniques and so this draws me toward his work. (e.g. Buddha in His Youth)

Two Trees 
The crying spider 
Buddha in His Youth
Redon does not outline his work and merely uses shadows to create substance and depth. The artwork bellow has a busy yet calm feel to it. He has used cross hatching on the main trunk of the tree which makes it seem rough and sturdy and tells the viewer that these trees/ this forest is old and holds many stories. the smaller branches are smooth and light. The leaves in the top left corner look so small and delicate in comparison to the trees.
The dark shadows behind the trees and in the hole of the center tree creates a feeling of depth. It creates a stark contrast and gives the trees substance. I feel as though if I were to go beyond the trees I would fall into nothingness.

Sources :
- https://www.odilon-redon.org/biography.html
- http://www.artic.edu/aic/collections/artwork/90316
- https://cool.conservation-us.org/coolaic/sg/bpg/annual/v14/bp14-08.html
- https://www.odilon-redon.org/I-Plunged-Into-Solitude.-I-Dwelt-In-The-Tree-Behind-Me.-Plate-9.html
- https://www.wikiart.org/en/odilon-redon/two-trees-1875
- https://steemit.com/art/@fineartnow/to-honor-old-masters-odilon-redon