Don't forget the little strip of background between the large tree trunks on the left.
Make a light bluey grey using ultramarine and burnt umber, a weak mix (more water); this will be used for all foreground trees.
Paint the whole trunk on the right leaving slight thin gaps so the white shows through in places.
Then using burnt umber paint over again, once more leaving slight thin gaps so that the blue grey shows through this time.
Make a darker mix with a touch more blue added, then add little strokes of paint to resemble the rough bark.
Using the same dark brown mix, paint in the branches using a rigger brush.
Holding the brush right at the end will give a more realistic look as the brush will shake and wobble as you paint the branches.
The left trunks are first painted with the blue grey mix. Then before they dry use a rigger and paint in the horizontal lines in the bark. Make them varied and patchy to be realistic.
Closeup showing bark detail.
While you have the dark brown mix handy. Add some more dry horizontal brush work to the nearest trees on the far bank, making them a bit stronger in tone than the distant ones.
Using your weak blue/grey mix paint the two other trunks.
While the center one is still wet drop in some burnt umber to give a bit of texture and shading with soft edges.
Wait until dry and apply some dark brown to the front tree leaving gaps allowing the grey to show through.
I realized the right tree needed the trunk extending down a bit more, so I lengthened the trunk with my darkest mix of brown.
Using a weak mix of raw sienna I painted in the reflections of the tree trunks and the house.
While wet I added a touch of weak burnt umber to represent the shadow side. Remember that the reflections of the trunks will not be seen right up to the edge of the bank.
We are painting the reflections on dry paper, not wetting at this stage. using the original colours paint in the tree foliage reflections and the far shrub reflections.
Paint a mirror image of the original shape as you paint them in.
Allow the last painting to dry completely. Now apply masking fluid over the painted tree trunk reflections to protect them from future washes.
Also add the odd horizontal streak of fluid which will preserve some of the light coloured paper and will look like sparkling ripples on the surface.
Then allow the masking fluid to dry completely. Now using a mop brush wet the wnole river water area with clear water. Brush lightly so the paint is not disturbed.
While the surface is wet , paint in the foliage reflections using light red and burnt umber. The colours will disperse slightly and give a soft edge.
Also paint the reflected bank using burnt umber.
Trying to show the reflections painted into the wet surface but it catches the camera flash and looks odd.
This photo shows the refections painted in and you can see where the masking fluid is showing.
After the paper is completely dry rub off the masking fluid. Make absolutely sure the paper is dry or it may tear the paper when removed.
Closeup showing the reflections.
If after removing the masking fluid you find some edges are too hard you can easily soften them with a damp brush.
The foreground grass was added by applying a wash of green ( ultra marine/lemon yellow) and while wet a touch of burnt umber . When dry the blades were added with a darker green ( add extra ultramarine ) and the odd white flecks produced by scratching with a hobby knife blade.