How to Care for a Star Jasmine Vine

Fertilize star jasmine only if its leaves turn yellow, and then only in spring. Select a formula intended for trees and shrubs, such as a granulated, 19-8-10 fertilizer with micronutrients. Sprinkle about 1/2 cup of the granules evenly over each 1 square yard of soil around the base of the vine and water well. Fertilizers of different strengths require different application rates; always follow the application instructions of the brand you choose.

The goal in watering star jasmine is to keep the soil evenly moist without being waterlogged. As the roots are getting established, water it two to three times each week. You'll know they're established when the vine begins putting out vigorous new growth. At that point, reduce the water until the plant is managing on rainfall. Overwatering exposes the plant to fungal root rot.

Occasional heavy pruning keeps star jasmine within bounds, when necessary. After the plant finishes flowering in spring, cut all its stems back by two-thirds to side shoots. Heavy pruning stimulates new growth at the base of the vine and along its woody branches.

Do an annual light spring pruning to remove dead, crowded or out-of-control shoots. Spring is also a good time to refasten escaped branches to their supports.

Star jasmine is not prone to any serious disease problems other than root rot from overwatering or poor drainage. Root rot surfaces as brittle, brown leaves and general weakening. It occurs when a soil-borne fungus kills enough of its roots that the plant can't get enough water to survive. Root rot is incurable; lift and dispose of an infected plant.

Watch for Japanese beetles, sap-draining scales and nearly invisible, web-spinning spider mites.

• Japanese beetles arrive in early summer to devour the leaves down to their veins.
• Scale insects resemble colonies of tiny barnacles on the stems and leaves. They drain sap and excrete large amounts of clear, sticky waste called honeydew.
• Spider mites look like tiny, scurrying dots as they ingest the leaves' cellular fluids.

Use cultural controls to manage light insect infestations:

• Early in the morning, when Japanese beetles are lethargic, handpick them from the vine and drown them in a bucket of soapy water.
  
• Prune branches with large scale colonies and dispose of them in sealed plastic bags. Disinfect the pruners in rubbing alcohol between cuts so they don't spread eggs or nymphs to other parts of the vine.
• Spray the jasmine thoroughly every two or three days with a strong blast of hose water to dislodge spider mites; make sure the water hits the undersides of the leaves.

When cultural controls aren't enough, consider spraying with ready-to-use, organic plant-based neem oil.

If a mild frost -- temperatures between 27 and 34 degrees Fahrenheit -- is expected, cover the star jasmine with a bed sheet or other light fabric. Remove the protection before temperatures rise significantly in the morning. Frost damage may result in twig dieback, sparse future flowering or death.