Plant of the Week: Aromatic Aster

Aromatic aster (Symphotricum oblongifolium) or fall aster is aptly named because it is a sure sign that fall is almost over and winter is just around the corner.  Only the frost aster (S. pilosum), the small white, weedy aster, appears on the landscape later.  This species is an easy one to identify because it has a more compact form due to its densely branched nature giving it a bushy appearance.  It also has larger flower heads, an inch or more wide, than most asters and anywhere from 20 to 35 bluish to purplish ray flowers in the head.  The disk flowers are typically yellow and turn lavender as the flowers mature. The 2" long leaves get progressively shorter as they ascend up the stems and are linear to oblong in shape, have short hairs, and attach directly to the stem.  Be aware that many of the cultivars or plants in the mainstream nursery industry are actually a hybrid of aromatic and New England aster (S. novae-angliae) and have a tendency to be larger plants with larger, more colorful flowers.  This is an easy to grow plant in full sun and prefers soils that are not rich, rather poor limestone soils, because it does not compete well against more aggressive species.  This species also likes it dry which makes it an excellent rock garden plant. The normal habitat for this species in Kentucky is along limestone cliffs and rock outcroppings and limestone glades.  The plant gets its name from the balsam like fragrance that is omitted when the leaves and flowers are crushed.  This is a great butterfly, bee, and insect attractor and on warm, sunny days the bugs will be all over the flowers as will the caterpillars of the silvery checkerspot.