|1||15C+||Indoor||Grow as a houseplant or under heated glass.|
|2||10 to 15C+||Indoor / Outdoor||Grow indoors, or outdoors in summer in a sheltered spot|
|3||5 to 10C||Tender||Grow outdoors in summer, and in a heated glasshouse in winter.|
|4||1 to 5C||Tender||Grow outdoors or under glass without risk of frost.|
|5||-5 to 1C||Half-Hardy||Hardy in coastal/mild/sheltered areas. Will not tolerate hard/sudden frost. May require winter protection in situ. such as fleece or straw mulch.|
|6||-10 to -5C||Hardy||May suffer at altitude, central/northerly locations, harsh winters, cold gardens and when grown in pots.|
|7||-15 to -10C+||Hardy||Will survive most severe winters but may be at risk in central/northerly locations and in pots. Top growth may be destroyed but will usually re-grow.|
|8||-20 to -15C||Hardy||Will survive severe winter, but may need protection when grown in pots.|
|9||-20C & Colder||Very Hardy / Hardy||in the severest European climates.|
5 In stock
Originating from Europe, Asia
Strong-growing deciduous perennial with broad, dark green leaves and compact clusters of large, violet-blue flowers in spring. Attractive to bees.
Grow in moist but well-drained soil in full/part shade.
Height and spread in 1 – 2 years 50 x 50cm