My tuppenceworth, and to be clear, I think this is a challenging subject & I'm not claiming that I'd have done any better ...
I don't think it helps that we've got an equal split along the horizon, dividing the image into two halves. Moving that shoreline up or down might have helped. The tree fills one side of the image, leaving the other side just (relatively) boring sea & sand. There's no interest in the sky either - clear blue skies tend to be quite boring photographically.
The texture of the tree trunk probably offers the most opportunity for interest, but it's a small part of the overall photo. It's what draws the eye (mine at least), but it's hard to appreciate the detail. A more abstract shot of close-up detail of the weathered wood might be better. A stronger composition might work. I'd have been tempted by the flowers to the right of the uncropped image - placing them as foreground interest, with the trunk leading away from them.