|My back yard is exposed to a two storie business building. Is there a fast growing tree or hedge that would reach 15 feet for privacy.|
|There are several possibilities to consider, so your choice will depend on the amount of space available and the growing conditions. Privet is a traditional hedging material and grows very fast, it also can be sheared to form a relatively tall narrow barrier.
Red barberry grows tall and has a fairly tidy natural shape, it can also be sheared. However, it is thorny and may not be a good choice if children play in the area. The reddish foliage can also be difficult to integrate into the landscape.
Many of the old fashioned flowering shrubs grow fairly quickly and can be used for informal hedging, meaning not trimmed into shape but planted in a line and allowed to grow to their full natural size. Forsythia will reach eight feet tall and wide very quickly. It offers the bonus of early spring bloom (bright yellow) and also holds its foliage late into the fall. The old fashioned white-flowered spirea would be another possibility.
Rose of Sharon (Hibiscus syriacus) is yet another possible choice. This plant can grow over eight feet tall and has a fairly upright shape. It can be pruned as needed in late winter or early spring and blooms heavily from mid summer onward. Newer varieties do not seed about the way the old fashioned ones did.
All of the above plants require at least a half day of sun (more is preferable) to grow well.
For sun to partial shade you might consider Euonymus "Manhattan" which is a fast growing plant that can be sheared.
If your area is shady you might consider installing a fence or lattice panels and growing a vine on it such as fall blooming clematis (very vigorous and large growing) or perhaps the evergreen English ivy (hedera helix).
I hope this gives you some ideas.