Paint each cardboard tube, inside and out and allow to dry for about 20 minutes. Tubes should be dry to the touch, but the cardboard should still feel damp and pliable.
While the cardboard tubes are drying, paint each dowel green. Using a block of floral foam or Styrofoam makes a great stand!
Cut each cardboard tube in half (2-inches long each).
Each tube will yield two flowers. You should have a total of eight painted tubes.
Flatten one end of the tube, then cut a 1/2" slit at both creases.
At the cut, fold the corner of the cardboard tube inward.
Add a dab of hot glue in the corners to hold them together, but do not glue the center yet as the dowel will be inserted here.
At the open end of the cardboard tube, cut triangles to form the tulip petals.
Add some hot glue to the center of the bottom of the tube and insert the dowel. Pinch the tube around the dowel to adhere the glue. Use the handle end of a paintbrush dipped in white paint to add polka dots to both sides of your flower.
To display, add some floral foam to a vase or tall container. Insert the dowels into the floral foam. To open the flowers a bit, simply reach inside the top of each flower and stretch the cardboard outward. Once the cardboard dries for several hours, the tulips will hold their shape as the dried paint makes them stiff and sturdy.