General native replacements for Buddleia, Butterfly-Bush,
clethra alnifolia cultivars
itea virginica cultivars
hydrangea arborescens cultivars
perennials and sub-shrub:
asclepias incarnata, a. tuberosa, a. syriaca
aster oblongifolius (syn. Symphyotrichum oblongifolius) ‘Raydon’s Favorite’
eupatorium dubium, and e. maculatum cultivars
Non native alternatives:
Buddleia is a popular shrub for sunny spots for its summer bloom of flowers (often purple) that attract butterflies, skippers, hummingbirds, and hummingbird moths which all like its nectar. The problem is that it can naturalize, and while not totally noticeable (seedlings with diluted flower colors can pop up in wild scrub up to an acre away) it can be pernicious and self-seeds itself prolifically in certain climates and soil conditions.
For those in the Mid-Atlantic region and down into the South there are many excellent alternatives. There are many shrubs and perennials that grow to the general size and shape of butterfly bushes and bloom around the same time if not slightly before and are even better nectar plants for butterflies.
First, native milkweeds, asclepias bloom during the same June-July time frame and are butterfly magnets. They also are the host plant for monarch butterfly larvae and are their preferred nectar source. You cannot go wrong planting tons of them.
For the beautiful alternatives for that purple or blue color, baptisia, an herbaceous perennial that acts something of a sub-shrub, blooms beautiful purple and blue lupine-like flowers on gorgeous powder-blue pea foliage in May to early June. That is earlier than most butterfly bush, but they give that great blue-purple color that is actually closer to true blue than any buddleia. Plant it with the southeast native cassia marilandica, and underused southeast native sub-shrub perennial with arresting exotic foliage and is the hardiest cassia, blooming in mid-late summer with yellow blossoms.
For other arresting blue blossoms, Agastache is another great source. Many cultivars are hybrids derived from crosses of a US Southwest native and non native species Cultivars ‘Blue Fortune’ and ‘Purple Haze’ can reach the heights and widths of butterfly bushes with huge wagging almost foxtail-like plumes of purple-blue and are supreme nectar sources and laugh off heat and are loved by pollinators, including bees which is always important. Most also have irresistible anise-mint fragrance and edible (but not to deer) leaves that can be used for the occasional herbal tea.
Bluebeard or caryopteris blooms in late summer and fall and are another source of true purple-blue color and are also extremely popular with pollinators. Their true blue flowers help bridge the summer to the fall bloom of aster oblongifolius an amazing native plant with a spicy and pleasant scented foliage and is one of the only critter-proof asters (a great replacement for mums) that also blooms very late, sometimes September, but often October to November. ‘Raydon’s Favorite’ a cultivar that can reach massive 4’ x 4’ shrub-like proportions provide very late season color and a last snack for pollinators before winter. The non-native aster ‘Monch’ is another beautiful supplement plant, it blooms super early sometimes July-August and forms a billowy 3 x 3 cloud of periwinkle blue.
Native shrubsare indispensable, spring blooming itea virginica or Virginia sweetspire provides early nectar sources for butterflies and have beautiful fall foliage. In people living in zone 7a and warmer, the tall itea ilicifolia or Hollyleaf Sweetspire with it’s fragrant foot-long racecems are surely a conversation piece. Combine with clethera, or summersweet, and ceanothus americanus, New Jersey Tea, for other mid-summer easy care bloomers that will attract tons of butterflies.
Finally, the creme de la creme are the perennial eupatorium, which often species can be considered rather tall and weedy there are many dwarf cultivars such as ‘Gateway’, ‘Little Joe’ and ‘Phantom’ of the meadow plant that attracts butterflies and bees to their dusky purple, pink and putty colored flowerheads like no other plant.
Truth be told there are many native alternatives, fothergilla, blueberries, the list really goes on, but these listed here I thought emulated the color and form of butterfly bush, without being butterfly bush. If you wish to stray from the use of unruly or just plain boring buddleia, these are are good place to start.