First time submitter - would appreciate feedback on what I can do to avoid being rejected in the future

Zoom in and look at the small patches of sky between the leaves - some strange artifacts there.

Stock contains 100 million plants, trees, bushes, grasses, leaves and flowers. 

Find other subjects that have less saturation. 

This is what you’re competing with:

https://stock.adobe.com/search?k=bamboo+tree  5.2 million

https://stock.adobe.com/search?k=bamboo  2.5 million

This is what Stock has to say about “similar content.”

https://helpx.adobe.com/stock/contributor/help/similar-vs-spamming.html

Try someting that is different, not a regular shot as there are many ‘similar’ shots in the data base.

This is an often-asked question that has been discussed on this forum for nearly a year. Do a search for “similar content” and perhaps you can glean some information on how to avoid (or at least learn to live with) this is particular reason for rejection.