Hi Tom, thank you so much for sharing your beautiful drawing. I think this piece is very lovely, capturing the characteristics of a horse accurately and depicting it using delicate lines and excellent value balance.
As to possible approaches to the background, I recommend that you check some of your fellow artists’ works for reference. As far as I know, we have at least two super stars here at the forum when it comes to animal portraits. You can check Deb’s and Lori’s works posted in this forum to see how they handle the background for animal portraits. Blurring the background like you often see in animal photos is a pretty popular approach, which is helpful to make the focal point stand out. Some examples include Deb’s pastel pencils drawings of Robin Redbreast, and Lori’s pastel drawing of parrot, all of which are marvelous. If you want to choose this approach, you would perhaps need to:
- delete the plants parts you’ve included in your current drawing
- digitally edit the background part of your photo reference so that you can see how it will look when blurred
- draw the background all over again using the edited photo reference
Or you can also skip step 2 & 3 and choose to add a completely different background. You can, for example, draw some flying leaves, flowers swinging in the wind etc. to add a sense of movement to your work. You can even decide to leave the background empty or non-objective as this artwork is basically a portrait, not a landscape including a horse like this one.
That said, I will share with you a completely opposite approach too, which is mine actually.
In this cat&plantlife ballpoint pen drawing, I drew all of these tiny plants very clearly, but made the overall background pretty dark. By so doing, the cat in the middle, despite the fact that it is not so detailed as the surrounding plantlife, ends up shining as the focal point because it is a white cat (Matt mentions this in the critique, at around 8:45 of the video). Right now, your horse is pretty light in the value, so if you are going to maintain the value as it is, darkening the background in some way, not necessarily with plantlife, would be another effective approach to a successful drawing.
Hope this helps a bit, and thank you again for sharing your work ! 
