Jasminum grandiflorum (synonym Jasminum officinale f. affine), a species of jasmine, has common names like Spanish jasmine, summer jasmine and poet's jasmine. Native to central Asia, this deciduous to partially evergreen climbing vine grows 15 to 25 feet tall. The pointy leaflets on the green leaves make an attractive foil for the 1.5-inch diameter flowers that are perfumed and white with pink-tinged petal edges. Grow it outdoors where winters are mild, in U.S. Department of Agriculture hardiness zones 7b and warmer.
Whether planted in a large container or in the ground outdoors, provide partial to full sun exposure to the poet's jasmine, meaning no less than six hours of direct sun daily. In hot summer climates or where air is arid, provide some shading across the hottest part of the afternoon for best looking foliage. If grown indoors as a houseplant, poet's jasmine needs as much direct sunlight as possible through windows.
From spring to late summer when the vine is actively growing and flowering, water the soil freely. The soil should be moist and well-draining, never dry or soggy/waterlogged. Touch the soil surface and to a depth of 1/2-inch with your fingertip to determine if the soil is slightly dry. If it is, you should add 1 to 2 inches of water. Irrigate to supplement natural rainfall. From mid-autumn through winter, reduce watering to prevent root rot or other fungal problems. Allow the soil to become slightly drier between waterings, adding no more than 1 inch of water.
Fertilize Jasminum grandiflorum only in spring and summer when the plant is actively growing. Container-grown plants can be fed with a water-soluble fertilizer that is rich in potassium, as recommended by the Royal Horticultural Society. Overall, a well-balanced fertilizer suffices (10-10-10). The third number refers to the amount of potassium, so that could be higher than the others. Do not fertilize plants in the fall and winter. Outdoor vines can receive water-soluble feedings, but a slow-release granular fertilizer and organic mulches and compost are the best approach.
Jasminum grandiflorum produces its pink flower buds on last year's woody stems in the earliest parts of midsummer, and the mature current year's stems in late summer and early fall. If you must prune for size or rejuvenation, cut back stems to 1/3-inch above healthy lower leaf, bud or side branch. Prune in late summer or early fall as flowering subsides to allow new growth to mature before the later fall frosts. Alternatively, if you live in USDA hardiness zone 7, consider pruning early in spring and allow regrowth to mature over summer and produce its flowers a bit later. Remove damaged or diseased stems any time you encounter them.
A healthy, vigorously growing poet's jasmine typically is free of insect pests. Inadequate lighting can lead to infestations of aphids on new growth; spray with insecticidal soap to rid the plant of them. Indoors, be particularly vigilant to squish white mealybugs on stems and leaf undersides. Red spidermites occur under leaves when temperatures are hot and there is no air movement. Spray leaves with regular water to deter spidermite colonies.