The Wisteria varieties listed are a selection we consider the best currently available from our original seventy plus forms that were collected locally and also imported from around the World . All are grafted to ensure early vigour and flowering . When planting always put the graft union a few inches below soil level . Any sucker growth that may sometimes occur coming from below the soil should be removed . Flowering times will vary depending on climate and some forms may take time to display their true flower colour . All prefer full sun positions but light filtered shade can be tolerated and on some forms can improve the flower colour . Colder climates tend to mask the strength of the scent and warm humid areas tend to amplify it . Pruning to promote flower production , once the plants have established and reached a desired size , is best done in late summer cutting back the seasons lanky water shoot growth down to three buds from where growth started the preceding spring. Extra watering when in flower will extend the display.