Brilliant Scarlet Oriental Poppy Seeds. Perhaps the most spectacular flower in the early summer garden with its brilliant red flowers and rich green foliage. Plants die back and go dormant during the summer. Try planting large flowering annuals immediately after poppies finish blooming or interplant late flowering perennials with established poppies. Avoid over-watering while dormant. Some suggested perennials to interplant are: Russian sage. coneflowers, daylilies, and lilies. Divide and transplant oriental poppies while they are dormant. Reaches a mature height of 75 cm (30").