Nerium oleander, known as oleander or rose bay, is found in the United States in hardiness zones 8 through 11. The plant's blooms appear in spring and come in a number of shades. However, several factors may inhibit the flowers' growth.
Oleanders tolerate a wide range of soil conditions, but if the soil isn't well-drained, the plant may not grow as well. Proper sunlight exposure is also necessary to the oleander, so without full or partial sun, its growth suffers.
Not pruning an oleander leads to inhibited flowering. Oleanders develop suckers that need to be removed so that the plant can flower. In addition, removing old flower clusters boosts the amount of new flowers produced.
Diseases and Pests
Certain diseases and pests damage plants to the point that they may not flower. Oleander leaf scorch affects the leaves of the plant, and can kill the plant if unattended. Oleander aphids eat young growth on oleanders, causing flowering problems.