Lavender 'Phenomenal' One of the hardiest lavenders! This hybrid lavender flowers in midsummer, a little later than English types, and has exceptional winter survival. Plants form a mound of silver foliage, above which long spikes of purple-blue flowers wave. Lavenders prefer well-drained soil, so plant in a raised bed if your soil is claylike. 'Phenomenal' is a butterfly-attracting flower that's ideal for nature gardens, herb beds, and cutting gardens. Zones: 5-9