Night jasmine, or Cestrum nocturnum, a member of the nightshade family, is also known as night-blooming cestrum and night jessamine. Although Cestrum can bloom during the day, flowers don't become fragrant until the evening hours. Hardy in USDA Zones 8 to 11, freezing will kill it back to the ground in Zones 8 and 9, but it happily returns in the spring if roots and trunk haven't been frozen. A sun worshiper, night jasmine thrives and blooms best when grown in full sun, but will tolerate partial shade. Established plants are easily maintained and typically ask for little more than protection from prolonged freezing.
Test your night jasmine's soil for pH level. The ideal range is 5.5-6.5 for these acid-loving plants, so make the appropriate adjustments.
Water deeply about once per week through the growing season. The root ball needs to be saturated to a depth of about 18 inches. The surface soil should be evenly moist, but not soggy or wet. These plant's don't like wet feet. Don't water night jasmine at all during the winter, unless you're experiencing an excessively dry season for your area. Winter rainfall will typically suffice.
Feed your night jasmine in early spring with a good quality all-purpose fertilizer that contains phosphorus. The phosphorus content is indicated by the center number labeled on the bag or container. Fertilize once monthly after that throughout the rest of the growing season.
Remove spent night jasmine blooms as they wilt to prevent them from forming seeds. Slough the blossoms off by gently running your hand across them. They'll fall right off, soon to be replaced with new flowers. This will direct the plant's energies and resources to producing lush foliage and even more blooms next year.
Prune night jasmine following its final blooming cycle of the season, from early fall to late winter depending upon your location, to prevent it from becoming leggy or rangy. Cut out any dead, damaged or diseased wood. Remove limbs that cross over each other to allow increased air circulation and sunlight to reach the plant's interior. Pinch or trim the tips of lateral limbs and stems to encourage new branching and blooming growth. Nip the ends of any stems that you think make the jasmine appear untidy.
Rejuvenate the older or overgrown night jasmine specimen by cutting it completely back to about 3 feet above ground level. Feed and water it well following such an aggressive pruning.
Apply a layer of organic mulch about 6 inches deep if you're expecting a prolonged hard freeze. Protect the roots by extending the mulched area as far as the longest stems reach. Wrap the plant's trunk in several layers of burlap or canvas, or any other heavy cloth that will allow for air circulation. Don't use plastic.