Cultivation notes
All jasmines need a fertile, well-drained soil in full or partial sun. Summer jasmine needs a sheltered spot, full sun and a south- or south west-facing aspect. Winter jasmine is more tolerant of partial shade and a south east or north west aspect. North and north east aspects are best avoided.
Frost hardy species are fine in an unheated conservatory or a cold greenhouse kept frost-free with a small heater. Tender species may require a minimum night temperature of 13-15ºC (55-59ºF).
Jasmines make lovely container specimens. Ensure you use a container with good drainage holes, cover the holes with crocks or grit, and fill with John Innes No 2. Leave space at the top for watering, and place the pot in bright but filtered light.
Watering and feeding
Water freely during spring and summer, when plants are in active growth. Reduce watering in winter. Outdoor plants may not need watering in winter, unless the weather is extremely dry or the ground frozen (in which case watering with lukewarm water may help). Indoor and glasshouse plants need only sparse watering in winter.
Feed containerised jasmine plants monthly with a high potassium liquid feed (such as tomato fertiliser). Border specimens can be top dressed with a balanced, granular fertiliser such as Growmore, or with a high potassium feed such as sulphate of potash. Seaweed feeds and wood ash are potential organic sources of potassium.
Hardiness
Jasminum nudiflorum (winter jasmine) is fully hardy and can be grown outdoors throughout the UK.
Jasminum officinale and J. officinale f. affine (syn. J. grandiflorum), the common summer jasmine, is frost hardy and suitable for outdoor cultivation against a sunny, sheltered wall in mild UK regions only. Elsewhere, it can be grown as a conservatory or glasshouse climber. The same applies to J. fruticans, J. humile, J. beesianum and J. × stephanense.
Jasminum fruticans and J.humile are evergreen or semi-evergreen. J. officinale and J. × stephanense are generally deciduous in the UK. J. beesianum is deciduous or semi-evergreen, depending on the local climate.
Jasminum parkeri, a dwarf shrubby jasmine from the Himalayas, is borderline fully hardy. It can be grown outdoors in mild areas, but is unsuitable for outdoor cultivation in cold areas and in most areas of northern England and Scotland.
The following jasmines are all half-hardy or tender, so must be grown indoors, or in a heated conservatory or glasshouse: J. rex, J. capense (syn. J. angulare), J. floridum, J. mesnyi, J. odoratissimum, J. polyanthum, J. sambac, J. dichotomum and J. azoricum.
Pruning and training
Summer jasmine: Is best pruned just after flowering, in late summer or early autumn. Early flower flushes develop on the previous year’s growth, but later flushes develop on the tips of the current year’s growth. Pruning after flowering gives the new growth time to mature and flower early next season.
Winter jasmine: Is best pruned in spring, immediately after flowering. Flowers develop on the previous year’s growth. Pruning after flowering gives the new growth time to mature and flower next season.
For both summer and winter jasmine, cut back flowered stems to a strong sideshoot lower down; thin out crowded, crossing or misplaced branches and remove weak or thin stems.
Both types of jasmine tolerate hard pruning and renovation. If the plant has outgrown its allotted space, cut back hard to within 60cm (2ft) of the base. Re-growth will be vigorous, so select strong shoots for training into the new framework, and remove unwanted shoots. The plant will take two or three years to start flowering again.