Ask Mr. Smarty Plants

Hydrangea quercifolia (oakleaf hydrangea) is native to North America, but  not to Texas. It requires shade and ordinarily blooms white, green and purple in June and July. Our Native Plant Database gives us this information about the oakleaf hydrangea:

"Conditions Comments: Susceptible to sunscald, chlorosis in alkaline soils, and winter dieback. Many weak, brittle canes are easily broken in wind and ice. Forms colonies from a shallow root system. Canes can be cut to the ground every two or three years to keep the shrub smaller, but if the canes are allowed to grow, the naturally peeling bark is attractive. Pest free. Prune immediately after flowering."

If, as you say, it bloomed in early spring, then there is something out of focus. In North Central Texas, you probably have alkaline soils, and the hydrangeas all need acidic soil.  Blooming early may have been the plant's need to survive by propagating itself, which it does by blooming and seeding. 

About all we can do is suggest some things you can try to make your plant feel more at home. First, if it is not in pretty good shade, it will not do well. Second, cut out the fertilizer, especially high-nitrogen lawn fertilizer. Nitrogen inspires heavy leafing, but not blooms. Prune it back, particularly the canes that bloomed in the spring. You didn't say how old the plant was; they usually have to mature two to three years before they begin blooming. You can't turn alkaline soil acidic, but you can try amending it by adding compost to the soil, and mulching. If you can get some pinebark mulch or even pine needles for mulch, they will add to the acidic character of the soil. We don't think you can expect another bloom this year-blooming, while necessary for plant survival, also requires a great deal of energy, and the plant is not only trying to adapt to conditions for which it is not suited, it is also recovering from blooming and trying to survive.

Hydrangea quercifolia

Hydrangea quercifolia

Hydrangea quercifolia

Hydrangea quercifolia