|Grow as a houseplant or under heated glass.
|10 to 15C+
|Indoor / Outdoor
|Grow indoors, or outdoors in summer in a sheltered spot
|5 to 10C
|Grow outdoors in summer, and in a heated glasshouse in winter.
|1 to 5C
|Grow outdoors or under glass without risk of frost.
|-5 to 1C
|Hardy in coastal/mild/sheltered areas. Will not tolerate hard/sudden frost. May require winter protection in situ. such as fleece or straw mulch.
|-10 to -5C
|May suffer at altitude, central/northerly locations, harsh winters, cold gardens and when grown in pots.
|-15 to -10C+
|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.
|-20 to -15C
|Will survive severe winter, but may need protection when grown in pots.
|-20C & Colder
|Very Hardy / Hardy
|in the severest European climates.
Out of stock
Originating from Japan, Korea, southern China and Southeast Asia
Will grow in dry shade where it spreads slowly. White flower spikes in late spring. Can be grown as a pond marginal.
May become invasive in damp soil. Gorgeously garish.
Eventual mature plant size :
|Season of interest