Hydrangea help?

[csziggy]

4. Could you have an oak leaf hydrangea?

Those are always white.

https://en.wikipedia.org/wiki/Hydrangea_quercifolia

There are some varieties of Hydrangea macrophylla that were selected to be white and are never a color. And there are varieties whose color is static and not dependent on soil chemistry.

For the varieties that do change color there needs to be aluminum in the soil:

Flower color in H. macrophylla is dependent on cultivar and aluminum availability. Aluminum is necessary to produce the blue pigment for which bigleaf hydrangea is noted. Most garden soils have adequate aluminum, but the aluminum will not be available to the plant if the soil pH is high. For most bigleaf hydrangea cultivars, blue flowers will be produced in acidic soil (pH 5.5 and lower), whereas neutral to alkaline soils (pH 6.5 and higher) will usually produce pink flowers. Between pH 5.5 and pH 6.5, the flowers will be purple (see image at left) or a mixture of blue and pink flowers will be found on the same plant.
http://www.usna.usda.gov/Gardens/faqs/hydrangeafaq2.html#How-change-flower-color