Native Perennials for Fall

It always seems the growing season is short in comparison to the long, gray days of winter. We want our colorful flowers to last as long as possible before surrendering our gardens to the first frost. Native perennials provide an array of flowers that bloom late into the growing season and support pollinators. Fall-blooming perennials provide much-needed pollen and nectar for the western honey bee (Apis mellifera) before winter. They also support pollinators whose life cycles begin later in summer or ones that migrate, like the monarch butterfly (Danaus plexippus) or ruby-throated hummingbird (Archilochus colubris).

Finding native perennials that bloom from late summer to fall can be more challenging than finding plants suited for spring or summer when there is a profusion of options in every nursery. However, there are a number of interesting perennials that feed pollinators and produce a pre-frost burst of color.

Joe Pye weed (Eutrochium purpureum). Photo credit: Glenn Koppel.

Joe Pye weed (Eutrochium purpureum) grows three to ten feet tall with masses of purplish-pink blooms providing nectar from August through September. Giant blue lobelia (Lobelia siphilitica) and its scarlet red relative, cardinal-flower (Lobelia cardinalis), grow one to four feet tall and provide nectar for many pollinators, including hummingbirds. New York ironweed (Vernonia noveboracensis) produces bright purple flowers, and Culver's root (Veronicastrum virginicum) has long plumes of white flowers. Both grow to six feet tall. All of these species do well in sunny to partly shaded areas with moist soils.

Cardinal flower (Lobelia cardinalis). Photo credit: Glenn Koppel.

Mountain mints (Pycnanthemum spp.) are a group of aromatic, deer-resistant plants that are pollinator magnets, attracting honey bees, beneficial wasps, butterflies, and moths. They produce small pinkish-white flowers from August to September. Short-toothed, also called broad-leaved mountain mint (P. muticum), prefers full sun to part shade with moist, well-drained soil. Appalachian mountain mint (P. flexuosum) forms a clump and is slower to spread.

Short-toothed mountain mint (Pycnanthemum muticum). Photo credit: Glenn Kopel.

A variety of goldenrods (Solidago spp.) provide sprays of bright yellow blooms that are drought tolerant, deer resistant, and good nectar sources. Goldenrods grow from one to four feet tall and flower until frost. You can find a wide variety of goldenrods that tolerate many light and soil conditions. Several to look for are zig-zag goldenrod (S. flexicaulis) for dry conditions as well as partial shade; gray goldenrod (S. nemoralis) is a short plant for dry, sunny conditions; and Solidago rugosa 'Fireworks' prefers moist, well-drained soils in full sun to part shade. Also, to correct a popular misconception, goldenrod does not cause hay fever because it does not have airborne pollen. The less conspicuous common ragweed (Ambrosia artemisiifolia) that blooms at the same time as goldenrod causes the allergic reaction called hay fever.

'Fireworks' goldenrod (Solidago rugosa ‘Fireworks’). Photo credit: Glenn Koppel.

Asters (Symphyotrichium spp.) are another large group of flowering plants that bloom in late summer and fall, often until frost. The group is diverse in color, height, and preferred growing conditions. New York aster (S. novi-belgii) and New England aster (S. novae-angliae) are perhaps two of the best-known fall asters. Both have purple flowers and grow in full sun. New York aster prefers drier conditions than New England aster. Aromatic aster (S. oblongifolium) has light blue flowers, often still blooming into late October or November.

If you plan to add native perennials for fall blooming to your garden and are concerned about the height that some species may reach, there are a couple of things you can do. One is to cut back late-blooming plants in mid-to-late June. You can cut one-third of the stem height. This will keep them shorter and bushier but still allow them to bloom in the fall, though flowering may be a little delayed. You can also look for dwarf cultivars of each species. ‘Little Joe’ Joe Pye weed grows to about three to four feet while ‘Baby Joe’ only reaches two to three feet. Likewise, there are dwarf cultivars of goldenrod. ‘Golden Fleece’ (15 inches tall) and ‘Little Lemon’ (12 inches tall) are perfect for containers and along pathways.

After planting and enjoying your late summer and fall blooming natives, leave the seed heads for birds to feed on and the stems for overwintering bees to use. Keep leaf litter on the ground for overwintering butterfly larvae. Revel in the last colors of the season while feeding the pollinators!