Broadleaf Ironweed blooms in August and September, producing large showy clusters of deep purple flowers with fine petals. Vernonia glauca is somewhat more compact than its cousin V. noveboracensis, and tolerates dryer conditions. Hiding in the background for much of the summer, it really stands out when in bloom in late summer. Butterflies cover the flowers, adding to the show.
'Iron Butterfly' Narrowleaf Ironweed has many bright purple star-like flowers that appear in late summer and fall. Foliage is delicate and thread-like on a compact plant. This Vernonia is very tolerant of site extremes, both dry and wet. Introduced by Dr. Allan Armitage and North Creek Nurseries. One of the native plants chosen by Piet Oudolf for the newly planted meadow garden at Delaware Botanic Gardens.
PRN Preferred: Not only beautiful purple flowers, but also delicate unusual fine foliage.
'Royal Candles' ('Glory') Spiked Speedwell has violet blue flowers in June and July over deep green disease resistant foliage. A fantastic plant from Heather and Mike Philpott of England. Veronica spicata 'Royal Candles' reblooms well if deadheaded.
'Georgia Blue' Speedwell is an attractive fine textured groundcover which is covered with small deep blue flowers in midspring into early summer. The ground hugging green foliage takes on hues of burgundy in the fall and winter. Since 'Georgia Blue' is drought tolerant as well as semi-evergreen, it would make an interesting green roof plant. Because of its extended bloom period, it also has an excellent application in containers and rock gardens.
Culvers Root has tall white spires of Veronica-like flowers in July and August. It tolerates wet sites very well. There's an amazing patch of Veronicastrum virginicum at the Scott Arboretum in full bloom during the Woody Plant Conference in July. It's worth a visit.
'Fascination' Culver's Root is a lovely tall native which is topped in July and August by graceful 12" lilac to pale blue spikes. The lanceolate leaves cover the tall stems in a distinct climbing whorl pattern. Veronicastrum 'Fascination' is a tough long lived perennial that is particularly effective in prairie gardens and the back of perennial beds and borders.
'Silver Gem' Prostrate Blue Violet has beautiful silvery heart-shaped foliage, crowned in March by bluish lavender flowers. The undersides of the leaves are burgundy, making a striking contrast to the silver-netted tops. The trailing habit of this tough native Violet makes it an excellent shade groundcover or rock garden plant. Viola 'Silver Gem' reblooms sporadically throughout the summer. Mt. Cuba found this little beauty and the folks at North Creek introduced it.