Your neighbor's yard is ablaze with color every summer, yet for some reason, those ornamentals you planted a few years ago still have not flowered.
Plants fail to flower for several reasons.
One of the more common reasons is plant immaturity. Trees, in particular, must reach a certain age before they begin to flower. Even if the plant is old enough, the growing conditions may be too poor to allow flowering. Plants that require full sun, for instance, may grow but fail to flower in the shade. Cold winter temperatures may kill the flower buds.