Here are the two sketches of the hedgerow in my backyard.  Left: I used a palette of Ultramarine Blue, Cadmium Red Light, Alizarin Crimson and Hansa Yellow Medium.  Right: I used Ultramarine Blue, Cadmium Red Light, Alizarin Crimson and a very cool yellow (I believe it is Winsor Yellow).  

Below are a few examples using variations of the same technique and including more of the surrounding landscape.  For me, it is playing between the paper being wet and dry ... taking advantage of it being dry to create hard edges where I want them and taking advantage of it being wet (or damp) to drop variations of color into the dampness for soft transitions between colors as well as shapes whether they be trees or land.

 

Just outside Murs, Provence, France

Hooper's Island, Maryland

Vermont

Mount Diablo, California

Provence

Maryland - I used ink line to define the trees after the watercolor dried.

New Jersey

New Jersey

New Jersey - ink lines added as watercolor was drying

Rather than adding the tree trunks and branches to dry paper blending into the damp foliage, I waited for the foliage of the trees to dry and created the illusion of the trunks and branches by painting the negative shapes of the purple mountain as it is seen through the branches of the trees.

I encourage you to experiment and play.