Step 1:
This paper is for the flowers, the backside is white. Prefold in half over these four lines.

Step 6:
Squash-fold the flap

Step 5:
Fold this flap straight upwards

Step 2:
Valley-fold over these four lines.

Step 4:
First, make 2 valley-folds below, on the right. Then, make 2 mountain-folds in the middle. And make 2 valley-folds at the top left.

Step 3:
Turn the model.

Step 10:
Press these edges downwards / flat

Step 8:
Unfold both folds

Step 9:
Fold this edge upwards.

Step 7:
Fold over these two lines

Step 16:
Repeat steps 13 to 15 on the other 3 same triangle flaps

Step 15:
Close the model again

Step 12:
Repeat steps 6 to 11 on the other 3 pieces indicated by the arrows.

Step 11:
Fold the triangle flap downwards by making a valley-fold over the green line.

Step 14:
Fold the triangle flap to the inside of the model

Step 13:
Pull these two petals outwards, in the direction of the arrows.

Step 21:
Bookfold one edge to the left.

Step 19:
Fold over these (prefolded) lines

Step 20:
Now you've made an extra petal.
Repeat steps 17 to 19 on the other 3 same places.

Step 18:
Pull the upper paper layer loose from both edges

Step 17:
Fold these two edges upwards

Step 22:
Fold the petal upwards

Step 28:
Pull this petal outwards and curl it by just rolling it up.

Step 25:
Fold over these two lines.

Step 26:
Repeat step 25 on the other 3 same places of the model.

Step 24:
Bookfold one edge to the left.

Step 23:
Repeat step 22 on the other 3 same petals of the model.
(These 4 petals are made of more paper layers then the other 4 petals)

Step 29:
This is the petal of step 28.
Repeat step 28 on the other 3 same petals.

Step 27:
Bookfold one edge to the left

Step 30:
Pull these 4 petals out of the model too and curl them by rolling them up outwards.

Step 31:
One cactus flower is done....

Step 32:
This is the leaf paper.
Prefold in half over both lines.

Step 33:
Make a valley-fold over these 2 lines.

Step 35:
Make a valley-fold over these 2 lines.

Step 34:
Make a valley-fold over these 2 lines.

Step 36:
First, (pre)fold the model in half over the line in the middle. Then, prefold over the 2 outer lines (The ends at the smaller arrows are folded to the prefolded centerline).

Step 37:
Now you've made 3 helplines for step 37 and 38.
Make an inside reverse fold over these 3 lines.
Do this by making a mountain-fold over the short line in the middle and a valley-fold over the 2 longer lines.
The line in the middle is on the same place as the folding line on the right in the picture of step 36

Make the same folds as above on the place indicated by the arrow (mirror wise)

Step 38:
Repeat step 37 two times, using the prefolded lines as guidance.

Step 39:
Insert a metal / florist wire in the model, you can use a little tape on the inside of the model to keep the wire on its place.

Step 40:
Glue a flower to the tip of the model.

Step 41:
Make enough of these pieces to get a nice arrangement.
Finally, place these pieces in a pot filled with foam.