An excellent way to attract butterflies to your garden is to plant annuals and perennials that are good nectar sources. Another irresistible attraction for butterflies is the butterfly bush (Buddleia davidii syn. Buddleja davidii).
Description
Butterfly bushes are medium-sized, woody shrubs. However, they're generally regarded as herbaceous perennials in Iowa because they typically die back to the ground each winter. Fortunately, their performance is not greatly affected by the extensive dieback. Butterfly bushes grow back rapidly after the dead wood is removed in early spring and bloom on the current year's growth. Plants generally have a loose, open, arching habit. By the end of summer, plants are often 5 to 6 feet tall.
The leaves of the butterfly bush are 4 to 10 inches long and 1 to 3 inches wide. Upper leaf surfaces are grayish to bluish green. The undersides of the leaves are grayish white.
In addition to attracting butterflies, the fragrant flowers also lure bees and hummingbirds to the garden. The small, 1/4 to 1/3 inch-wide flowers are borne on dense, 6 to 12 inch-long spikes (panicles). In Iowa, flowering typically begins in early summer and continues until frost. Buddleia davidii cultivars possess a wide range of flower colors including white, yellow, pink, blue, violet, and purple. The flower panicles on some varieties are upright, while others have a graceful, arching form.
Growing Conditions
Butterfly bushes perform best in moist, well-drained soils in partial to full sun. Avoid wet, poorly drained sites. Also, select sites that provide winter protection. Butterfly bushes planted in open, exposed sites are more likely to be destroyed by harsh, winter weather.
Maintenance practices are fairly simple. Remove spent flower panicles to encourage additional bloom through the summer. In late fall, mound a few inches of soil around the base of each plant. The soil protects the plant crowns and will hopefully prevent their complete destruction.
The following spring, remove the soil and prune the plants back to within a few inches of the ground. Butterfly bush is notorious for emerging late in the spring. It is typical for new growth to wait until early June to emerge. When no new growth is observed in the spring, don't assume the plant has died. Only plants with no growth by mid to late June can be considered potentially dead.
Invasive Potential
For Midwestern gardeners, the invasive potential of butterfly bush is considerably lower than in regions such as the Pacific Northwest and parts of the Northeast, where the shrub readily self-seeds and has escaped into natural areas. In Iowa and much of the Upper Midwest, cold winters reduce seedling survival, and widespread naturalized populations have not been reported. However, butterfly bush is capable of producing large quantities of wind-dispersed seed, so gardeners should not assume there is no risk. Select sterile or low-fertility cultivars when available, remove spent flower heads before seed dispersal, and monitor for volunteer seedlings near plantings to prevent any potential spread.
Potential Problems
Insects and diseases are generally not major problems in Iowa. The biggest threat to the butterfly bush is our harsh winter weather.
Notable Cultivars
There are numerous varieties of butterfly bush available to home gardeners. A listing of some of the widely sold varieties, plus a brief description of each, is provided below.
- 'African Queen' - dark violet flowers, panicles are 8 inches long.
- 'Black Knight' - dark purple flowers are produced on 6 to 8 inch-long panicles.
- Butterfly Magic™ - three different cultivars in one pot; Black Knight, Pink Delight, and White Profusion
- 'Dartmoor' - mauve-purple flowers are borne on large, multi-branched flower heads.
- 'Dubonnet' - violet-purple flowers.
- 'Empire Blue' - violet-blue flowers with orange eyes are borne on 6 to 12 inch-long panicles.
- 'Harlequin' - flowers are reddish purple, green leaves have creamy white margins.
- 'Honeycomb' - yellow flowers have orange eyes.
- Mop Top® (Buddleia alternifolia 'SMNBAB') - compact variety, lavender-blue flower clusters are held above dense foliage, creating a rounded mop-top effect.(Walters Gardens cultivar description)
- 'Nanho Blue' - compact variety, mauve-blue flowers are produced on 4 to 6 inch-long panicles.
- 'Nanho Purple' - compact variety, produces magenta-purple flowers.
- 'Pink Delight' - true pink flowers are borne on 6 to 12 inch-long panicles, gray-green foliage.
- 'Royal Red' - flowers are purple-red, panicles are 6 to 12 inches long.
- 'White Profusion' - pure white flowers are borne on large, arching panicles; vigorous variety with a graceful, fountain-like habit
- Cascade Collection - arching or cascading habit with large pendulous flowers; reduced or no seed set
- 'Grand Cascade' - enormous light lavender-purple flower panicles, 12 to 14 inches long and up to 4 inches thick.
- 'Lilac Cascade' - pale lilac flowers are borne on huge, cascading panicles 12 to 18 inches long.
- 'Pink Cascade II' - large pink flowers are produced on 12-inch-long arching panicles; improved over the original selection with larger, puffier flower clusters and a later bloom season.
- 'Violet Cascade' - deep purple flowers are borne on cascading panicles
- Humdinger® Collection - compact, early blooming, shorter
- 'Gold Drop' - compact variety, purple flower panicles are borne over dense golden foliage
- 'Little Angel' - compact variety, pure white flowers are produced on 10 to 12 inch-long panicles
- 'Lavender Cupcake' - compact variety, light lavender-purple flowers are borne on exceptionally long 12-inch-long panicles
- 'Magenta Munchkin' - dwarf variety, deep magenta flowers are produced on long, conical flower spikes; dense, rounded habit.
- 'Orchid Annie' - compact variety, orchid-purple flowers are borne on long panicles
- Lo & Behold® Series - small and mounded habit, reduced seed set
- 'Blue Chip' - compact, nearly sterile variety, produces blue flowers continuously from summer until frost.
- 'Blue Chip Jr.' - improved compact variety, abundant blue flowers are borne on a dense, mounded plant.
- 'Ice Chip' - low-growing, spreading variety, produces white flowers over a long bloom period.
- 'Lilac Chip' - compact variety, produces lilac-purple flowers throughout summer and fall.
- 'Pink Micro Chip' - dwarf variety, soft pink flowers are borne on a compact, rounded plant.
- 'Purple Haze' - spreading variety, rich purple flowers are produced on gracefully arching stems.
- Miss Series - medium height, compact habit, reduced fertility or seedless
- 'Miss Molly' - produces vivid reddish-pink flowers from summer into fall.
- 'Miss Pearl' - crisp pure white flowers are produced continuously from summer into fall.
- 'Miss Ruby' - bright magenta-pink flowers are borne on well-branched plants.
- 'Miss Violet' - seedless variety, produces dark violet-purple flowers throughout summer and fall.
- MONARCH® Collection
- 'Blue Knight' - produces blue-violet flowers on upright plants.
- 'Cherry Royale' - rich cherry-red flowers are produced on upright plants.
- 'Crown Jewels' - compact variety, magenta-purple flowers are borne on upright, branched stems above bright golden foliage.
- 'Dark Dynasty' - dark purple flower spikes are produced over a long summer bloom season.
- 'Darkest Night' - deep purple flowers are borne on dense flower spikes; noted for exceptionally dark flower color.
- 'Glass Slippers' - light blue flowers are borne on large flower spikes.
- 'Princess Pink' - bright pink flowers are borne on large panicles.
- 'Prince Charming' - bright cerise-pink flowers are borne on 10-inch-long flower spikes; upright, rounded habit.
- 'Queen of Hearts' - vibrant magenta-red flowers are produced on 7 to 9 inch-long panicles; compact, rounded habit.
- Pugster® Series - short, stocky, and compact habit with large flowers
- 'Pugster Amethyst' - rich amethyst-purple flowers are borne on sturdy stems.
- 'Pugster Blue' - produces oversized blue flower spikes on sturdy stems.
- 'Pugster Periwinkle' - lavender-blue flowers are produced on large flower spikes.
- 'Pugster Pink' - large pink flower spikes are produced from midsummer through fall.
- 'Pugster White' - fragrant white flowers are borne on exceptionally large panicles.
Alternate-Leaf Butterfly Bush
While varieties of Buddleia davidii are the most widely planted butterfly bush in the Midwest, the alternate-leaf butterfly bush (Buddleia alternifolia) is another possibility for home landscapes. This species is slightly more hardy than Buddleia davidii. As a result, it usually doesn't die back to the ground during winter. Plants are large, arching shrubs that grow approximately 10 feet tall. Lilac-purple flowers appear in June on the previous year's growth.
More Information
- Summer Blooming Perennials
- Perennials for Sun (PDF)
- Summer-Blooming Shrubs for Iowa
- Summer Blooming Trees
- Alternatives to Common or Invasive Landscape Plants
Photo credits: 1: Aaron Steil; 2: Aaron Steil; 3: Aaron Steil; 4: Aaron Steil