Through much of the Northern Hemisphere, October means harvest time. Golden shocks of hay and brilliant orange pumpkins bask under deep blue October skies. Brilliant autumn foliage flames overhead. October's color, however, isn't confined to plants that have finished their summer's work. Many plants have flowers that are in season in when October's cooler, shorter days arrive. They provide color and form during the garden's final weeks.
Windflower (Anemone x hybrida 'Lady Gilmour')
Windflower (Anemone x hybrida 'Lady Gilmour' ) is a mounding, buttercup family perennial native to Japan. Windlfower, hardy to minus 30 degrees Fahrenheit, stands from 3 to 4 feet tall and up to 2 feet wide. This plant has attractive, deep-green lobed foliage and long, branching stems. Between August and October, its yellow-centered, pink flowers appear. This largely insect-and-disease-resistant plant likes partial shade and fertile, moist well-drained soil. Plants in full sun are vulnerable to leaf burn. Use windflower, advises the Missouri Botanical Garden, in woodland gardens or perennial borders. Where winters are cold, advises the Missouri Botanical Garden, the plant benefits from mulch. Stake taller plants as needed.
Aromatic Aster (Aster oblongifolius 'October Skies')
Aromatic aster (Aster oblongifolius 'October Skies'), a perennial hardy to minus 40 degrees F., usually stands 18 inches to 2 feet high with an equal spread. 'October Skies,' an aster cultivar, seldom exceeds 18 inches. Its smooth, 3-inch deep green leaves emit a pleasant fragrance when bruised. From August to October, the plant's stems have profuse clusters of blooms. The flowers, with deep blue rays (petals) around flat yellow centers, bring butterflies to the garden. Although susceptible to wilt and powdery milder, the aromatic aster is relatively problem free. Mass it, suggests the Missouri Botanical Garden, in wildflower or woodland gardens. The drought-tolerant plants are happiest in full sun and dry to averagely moist sandy or clay soil. (References 2 and 4)
Turtlehead (Chelone glabra)
Turtlehead (Chelone glabra), a plantain family perennial, grows along streams and in moist woods and swamps. The 2- to 3-foot-high plant is hardy to minus 40 degrees F. Its upright clumps, up to 30 inches wide, have lance-like, toothed deep green leaves. From August to October, its dense spikes of pinkish-white, hooded blooms appear. They resemble snapdragon flowers. Plants in dry soil or with inadequate air circulation may develop mildew. Turtlehead, says the Missouri Botanical Garden, is a good choice for shade or bog gardens, or for planting along ponds. Plants like partial shade and moist or wet, humus-rich soils. Those in full shade become leggy and may need staking. In sunny locations, they benefit from a layer of leaf compost. Pinch turtlehead back in spring to keep it from becoming too tall.