Known as pikake in Hawaii and Arabian jasmine elsewhere, Jasminum sambac's tiny white flowers pack a wallop when it comes to fragrance. Native to India, this olive-family plant thrives in U.S. Department of Agriculture plant hardiness zones 9 through 11. Gardeners in colder regions can grow it in containers indoors.
Light and Temperature
Give the jasmine a sunny, warm location. Daytime temperatures between 80 and 90 degrees Fahrenheit and night-time temperatures between 70 and 80 degrees are optimal for flower production. In fact, just one night with temperatures in the low 60s “can shut down flowering for one to two weeks,” according to tropical plant and social scientists at the University of Hawaii Cooperative Extension.
Water and Fertilizer
The moisture content of the soil in which the jasmine is planted is the most important aspect of its care.
Excessive moisture will kill the jasmine, so water the plant only when the top 2 inches of soil is dry. As a general rule of thumb, provide the plant, whether grown in a container or in the garden, one inch of water per week.
Promote more and larger blooms by fertilizing an outdoor jasmine with a high-phosphorus fertilizer, such as 10-30-10. A water-soluble liquid 10-10-10 fertilizer works well for an indoor jasmine. Apply fertilizer three times during the year, with the first application at pruning (in late fall or winter, after the plant finishes blooming) and two more applications during the growing season.
For an outdoor jasmine, use 1.5 pounds of the fertilizer granules per 250 square feet of planting area. Sprinkle the granules evenly on the soil at the plant’s drip line, completely surrounding it. Use a hand rake to scratch the fertilizer into the soil and water as you normally do.
Apply a liquid fish fertilizer for an indoor-grown jasmine at the rate of 1 tablespoon dissolved in 1 gallon of water. Pour the solution over the soil, stopping when it runs from the bottom of the pot.
To maintain the size and shape of the jasmine, prune it when it stops flowering, in fall or winter. Depending on the size of the plant, use hedge trimmers or hand pruners you’ve disinfected in a solution of 1 part of household bleach to 3 parts of water.
Remove any crusted-on soil from pruning equipment before soaking it in the bleach solution for five minutes. Rinse the tool with water before using it on the plant.
Cutting the plant back to a height of 2 feet will rejuvenate it for the following season. To promote additional flowers during the growing season, trim the tips of shoots back to just above a lateral bud. These buds are located along the sides of the stems, not at the tips.
Arabian jasmine is listed as a Category II invasive plant in Florida.
Spider mites are the most common pest you’ll find on an Arabian jasmine. It's difficult to see them with the naked eye, so check the leaves for tiny black or brown dots that move. Prevent spider mite infestations by keeping the jasmine’s leaves dust-free.
Control the pest with a pre-mixed commercial insecticidal soap spray or mix 5 tablespoons of a concentrated product in 1 gallon of water. Water the jasmine as you normally do before the application. Spray the solution on all surfaces of the plant, ensuring they are completely covered. This spray will also control aphids but requires another application after 10 days.
Insecticidal soap may harm new foliage and shouldn’t be applied to the jasmine when outdoor temperatures exceed 90 degrees Fahrenheit.
Insecticidal soap spray may irritate your skin, so wear protective clothing and eye protection during the application. It may also irritate your lungs, so wear a breathing mask to avoid directly inhaling the fumes. As when using any insecticide, wash hands and clothing with soap and water afterward.