Downy Skullcap has attractive foliage and flowers; it is one of the more showy species in this genus. It is similar to Agastache foeniculum (Anise Hyssop) in the appearance of its foliage and habitat preferences, but its flowers are larger and more attractive. Therefore, it's surprising that this plant is not grown in flower gardens more often. Distinguishing Scutellaria spp. (Skullcaps) is rather tricky, but here are some key characteristics of Downy Skullcap
This perennial plant is 2-3' tall and little branched, except near the apex. The erect central stem is whitish green, bluntly 4-angled, and finely pubescent. The opposite leaves are up to 3" long and 1½" across; they are ovate in shape and crenate along their margins. The upper leaf surface is pale-medium or yellowish green and glabrous or nearly so (except for young leaves), while the lower leaf surface is whitish green and finely pubescent. The pubescence on the elevated veins of the leaf undersides is somewhat longer than the pubescence between the veins. The petioles are short (up to ½" in length), whitish green, and finely pubescent. From the middle to upper leaf axils, short secondary stems with smaller leaves may form. The upper stems terminate in spike-like racemes of flowers up to 6" in length. These racemes are held upright and they have densely-spaced pairs of flowers. Each flower has a 2-lipped tubular corolla about ¾" long that is mostly blue-violet, and a short tubular calyx about ¼" long that is whitish green and finely pubescent. The reproductive organs of the flower are inserted within the corolla. The upper lip of the corolla is hood-like with lateral margins that are curled back, while its lower lip is larger and broader; there is a conspicuous patch of white in front of the throat of corolla. A very fine pubescence (canescence) covers the outer surface of the flower, particularly on the hood (visible with a 10x hand lens). The calyx has a conspicuous protuberance on its upper side. Both the central rachis of each raceme and the pedicels of the flowers (up to ¼" in length) are whitish green and finely pubescent. At the base of each pedicel on a raceme, there is a small leafy bract up to ½" long that is lanceolate or elliptic in shape. None of the hairs on this plant are glandular or sticky. The blooming period occurs from mid- to late summer, lasting about 1-1½ months. There is no noticeable floral scent. The flowers are replaced by oddly shaped capsules that contain 2-4 nutlets. The upper surface of each capsule is concave with a protuberance on one side. At maturity, these capsules turn brown and split open to release their nutlets; this process may be facilitated by raindrop logistics. The root system is rhizomatous, often forming tight colonies of clonal plants.
Flower-Visiting Insects of Downy Skullcap in Illinois:
Scutellaria incana (Downy Skullcap) (Bumblebees collect pollen or suck nectar; beetle activity is unspecified; other insects suck nectar & are non-pollinating; wasps suck nectar by perforating the flower, while short-tongued bees suck nectar from these perforations [sn@prf]; most observations are from Robertson, although some observations are from Hilty and MacRae as indicated below)
Bees (long-tongued) Apidae (Bombini): Bombus auricomus sn, Bombus griseocallis sn, Bombus impatiens sn cp, Bombus pensylvanica sn cp fq, Bombus vagans sn cp; Anthophoridae (Ceratinini): Ceratina dupla dupla sn fq np
The preference is partial sun and mesic to dry-mesic conditions. Full sun or light shade and moist conditions are also tolerated. The soil can contain loam, clay-loam, or some rocky material, which corresponds to the conditions in which this plant normally grows. Foliar disease rarely bothers this plant; some of the lower leaves may turn yellow and drop off the stem if there is a severe drought, but this member of the Mint family withstands dry conditions rather well. Occasionally, insects may chew holes in the leaves, sometimes causing major damage. Overall, this plant is easy to grow in a garden setting. Range & Habitat