Panorama Snapdragon Seeds. Exceptionally vigorous plants 50-60 cm (20-24″) tall with flowering so prolific, the foliage almost disappears! Clear, vibrant colours and a good garden habit make this the recommended variety for mass plantings. While it performs best in cooler weather, they will generally bloom for the entire growing season. They may languish somewhat during the very hottest (30 C and up) humid summer weather but usually rebound when temperatures moderate.