Step 1:
The papers for the flowers are 3x3inch.
Prefold over these 4 lines.

Step 2:
Valley-fold over the 2 lines at the bottom right. Then mountain-fold over the 2 diagonal lines. And valley-fold over the 2 lines at the top-left.

Step 3:
Valley-fold over these 2 lines.

Step 4:
Unfold the folds of step 3.

Step 5:
Valley-fold the end at the bottom of the arrow upwards.

Step 6:
Push/press the edges indicated by the arrows flat.

Step 7:
Valley-fold the flap downwards.

Step 8:
Repeat steps 3 to 7 on the backside.

Step 9:
Prefold over this line.

Step 10:
Open the model, see arrow.

Step 11:
Mountain-fold the center downwards.

Step 12:
Push the model inwards again, see arrows,
by folding over these (prefolded) lines.

Step 13:
Push the 2 corners indicated by the arrows against each other.
Then turn the model.

Step 14:
Squash-fold the petal indicated by the arrow downwards, against the fingers which are holding the model.

Step 15:
Repeat step 14 on the other three petals, see arrows.

Step 16:
Mountain-fold over these 4 lines.

Step 17:
Mountain-fold over these eight lines.

Step 18:
Valley-fold the tip of the petals upwards.

Step 19:
Make enough of these flowers for one plant.

Step 20:
Roll up about five a4-papers together.

Step 21:
Valley-fold the top in half over this line.

Step 22:
Wrap tape around the top.
(You can use strong metal/florist wire instead of these five white a4-papers too).

Step 23:
Use one crumpled brown a4 paper for the main branch.

Step 24:
Wrap the brown paper around the white main stem.

Step 25:
Press the top inwards from all angles

Step 26:
Fold/bend/curve the stem, use the picture of step 27 as guidance

Step 27:
The arrow shows how the main-stem should look

Step 28:
The other stems/branches are made of brown crumpled 6x6inch papers. Fold in half.

Step 29:
Fold in half.

Step 30:
Fold in half.

Step 31:
Fold in half.
If necessary, fold in half one more time.

Step 32:
Fold the top of the stem in half.

Step 33:
Bend/curve the stem.

Step 34:
Use metal/florist wire if your branches are not strong enough to hold the flowers.

Step 35:
Open the bottom of the flower on the left and glue it to the top of the stem. Glue the edge of the flower on the right inside the opening of the stem. Glue the little flap of the flower in the middle in the opening of the stem

Step 36:
This is another example how to make the glueing more easy: Glue the edge of the flower inside the opening of the flower below, see arrows.

Step 37:
Glue more flowers to this stem, see final picture as guidance. Make enough of these branches with blooming flowers for one completed plant.
These branches are glued and/or taped to the main-stem, see final picture

Step 38:
I wrapped a newspaper around the base of the main stem and placed it in this white pot.
You can use florist foam or large paper balls too, if you want.
Finally I covered the newspaper with smaller paper balls.

This is a video with me folding the Bonsai Origami Dogwood Tree: