‘Hakone Double Blue’ balloon flower Platycodon grandiflorus 'Hakone Double Blue' Type:perennials Notable Traits:resistant: deer Hardiness:Zone 3 – 8 Mature Height:18-24in Light:part to full sun (6 hours or more sun) Water:requires regular watering Bloom Color:blue Bloom Shape:cup Bloom Time:fallsummer Foliage:green Description Beautiful double flowering bells of violet-blue make quite a splash on this 15-24″ tall perennial in summer. Long blooming period, the flowers make great cuts.