Daylilies (Hemerocallis ) are one of the most diverse and heavily hybridized perennial flower  in existence. The variation of flower forms, sizes, not to mention color and color variations is satggering in the number of cultivars . With over 50,000 registered day lilies recognized by the American Daylily Society it is hard to imagine what else one could expect to find new or different in a daylily.
The amazing largely overlooked attribute of day lilies  is the other extremely variable characteristics that day lilies exhibit. Bloomtime, Foliage type,  Foliage color, Scape height,  Scape color are just a few of the largely overlooked attributes in Hemerocallis.
    To really explore these attributes one must look to the original species and closely  related cultivars.
The H. citrina species is characterized by lemon yellow flowers, trumpet shape and typically a fragrance. There is a large number of H. citrina  species variants. Because the originally species have been cultivated for so long it is difficult to absolutely figure out which variants are true species types originating from the wild or early hybrids that occurred naturally or through hybridizing. These variations typically include scape height, flower shape and bloom time.
One interesting attribute of the H. citrina types is the foliage. Largerly unknown there is a minor fungus called leaf streak whoch affects most day lilies. While mostly innocuous Leaf Streak can make older leaves brown with yellow streaking in extreme cases such as highly susceptible cultivars or stressful conditions, Leaf Streak can be very unsightly. The H. citrina types all exhibit except able resistance to Leaf Streak. While not immune to Leaf Streak H. citrina  types show only minimal infection and almost never any yellow streaking. Because of this most H. citrina types assays have impeccable clean foliage. Added to the fact that all have a blue-green foliage these day lilies can almost be appreciated by their foliage alone. The new shoots that emerge in the spring exhibit a radiant lush coloration that catches the eye from a distance.

H. citrina H. citrina vespertina, H. citrina thunbergii, and H. altissima all fall into the H. citrina complex.  These day lilies  all are unusually tall for day lilies 48 inches are more and buds coints of over 20 per scape. The classic H. citrina is about 48' in height with a bud count of around 20. The foliage is typically about 24" in height and a blue green. Blooming in mid season (mid July here in Vermont) H. citrina last into August.