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How to Grow Buddleia – Butterfly Bush

Buddleia, butterfly bush

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Buddleia or Buddleja — commonly called butterfly bush — produces a great profusion of mostly long, colorful racemes in shades of lilac and purple mostly. Flowers appear in tapered sprays at branch tips. The blooms attract butterflies. They are also excllent cut flowers with a long vase lift.

Buddleia is an evergreen, semi-evergreen, or deciduous plant depending on where it is grown. Buddleia has a fountain to spray-shaped habit. It can grow from 4 to 8 feet tall and 3 to 6 feet wide depending on the variety. Buddleia favors just moist, fertile soil, but will grow in average soil and is drought-tolerant once established.

Buddleia’s flowers are lightly scented. Place Buddleia where the flower scent and color can be appreciated and where attracted butterflies can be seen. Buddleia is at home in informal mixed border. It is often placed in the back or midground of cottage gardens.

Get to know Buddleia

  • Plant type: Evergreen, semi-evergreen, or deciduous shrub
  • Growing zones and range: Zones 5-10
  • Hardiness: Hardy to Zone 5; tops dies back to the ground in zones 5 and 6.
  • Height and width: 4-8 feet tall; 3-6 feet wide
  • Flowers: Panicles of small, tubular, fragrant flowers in shades of pink, white, purple, or red.
  • Bloom time: Summer
  • Uses: Place at rear of sunny flowerbed or near sitting area to show off blossons and butterflies; makes good cut flower.
  • Common name: Butterfly bush
  • Botanical name: Buddleia or Buddleja
  • Family name: Scrophulariaceae
  • Origin: Tropical and tremperatre regions in America, Asia, and South Africa

Where to plant Buddleia

  • Plant Buddleia in full sun or light shade. Full sun yields the best flowers.
  • In very hot summer regions, Buddleia is best planted in full sun to part shade.
  • Average to sandy soil is best; soil must be well-drained.
Pink Buddleia in the sun
Pink Buddleia in the sun

When to plant Buddleia

  • Plant established Buddleia in either spring or fall.
  • Set container-grown Buddleia outdoors in spring or in fall in mild-winter regions.
  • Sow Buddleia seeds in spring.
  • Start Buddleia softwood cuttings in summer.

Planting and spacing Buddleia

  • Sow seeds 1/8 to ¼ inch deep in six-packs or flats filled with sterile seed-staring mix or polling soil. Sow seed outdoors in evenly prepared soil
  • Space plants 3 to 10 feet apart depending on the variety.
  • Buddleia is fountain- to vase-shaped if left unpruned; pruned speciments grow 5 to 8 feet tall

How to water and feed Buddleia

  • Keep the soil evenly moist until Buddleia is established; Buddleia is drought-tolerant once established.
  • Fertilize Buddleia with an all-purpose fertilizer in spring.

Buddleia pruning and care

  • Prune Buddleia in either spring or fall to encourage blooming
  • Periodically remove some older branches.
  • Prune out all dead or damaged stems in spring.
  • Some Buddleia varieties bloom only on wood that grew the previous year. Buddleia davidii, the most common Buddleia, blooms on new wood produced each spring.
Buddleia davidii against a blue mid-summer sky
Buddleia davidii against a blue mid-summer sky

Buddleia propagation

  • Sow Buddleia seed in spring at about 70°F.
  • Root semi-ripe cuttings in summer. Root hardwood cutting in autumn.

Buddleia varieties to grow

  • Buddleja alternifola, Fountain buttery bush, deciduous Chinese origin; grows to 12 feet tall and wide; bears small clusters of fragrant lilac-purple flowers; prune after bloom.
  • B. asiatica, evergreen in Zones 8 and warmer; grows 10 to 15 feet tall and wide; bears 10-inch spikes of tiny very fragrant flowers; prune after bloom; will die back to the ground in freezing weather.
  • B. crispa, decidious, native to Himalayas; grows 6 to 10 feet tall and wide; bears 4-inch clusters of fragrant lilac flowers; cut back nearly to the groudn in winter in cold-winter regions; grows well in containers.
  • B. davidii, Butterfly bush, Summer lilac; semi-deciduous native ot East Asai; grows 5 to 15 feet tall; flowers spikes 4 to 24 inches long appear in arching clusters; cut back before spring growth starts. Many excllent cultivars — ‘Empire Blue’ large dark blue flowres; ‘Fascination’ salmon-pink flowers; ‘Harlequin’ variegated leaves, maroon flowers; ‘Royal Red’ dark purple-red leaves; ‘Black Knight’ deep purple flowers; ‘White Bouquet’ white flowers; ‘Wilsonii’ drooping light pink-prple flowers.
  • B. globosa, Orange butterfly bush, evergreen to semi-evergreen from South America; grows 10 to 15 feet tall and wide; orange balled flowers in spikelike clusters to 8 inches long.
  • B. ‘Lochinch; mostly decidous; grows 5 to 8 feet tall and wide; gray foliage with light lavender-blue flowers in late summer and fall.
  • B. marrubiifolia, Wooly butterbly bush; evergreen in mild winter regions; grows to 5 feet tall and wise; dense silvery foliage; orange flwoers in spring and summer; prune after flowering.
  • B. x weyeriana, hybrid resembles. B. globosa; deciduous except in mild-winter regions; elongated orange yellow-flower culsters in late spring or early summer: grows 6 to 10 feet tall; cultivars include ‘Bicolor’ with mauve-pink with peach-pink centered flowers; ‘Sungold’ blooms orange; ‘Honeycomb’ bloom yellow.

Written by Stephen Albert

Stephen Albert is a horticulturist, master gardener, and certified nurseryman who has taught at the University of California for more than 25 years. He holds graduate degrees from the University of California and the University of Iowa. His books include Vegetable Garden Grower’s Guide, Vegetable Garden Almanac & Planner, Tomato Grower’s Answer Book, and Kitchen Garden Grower’s Guide. His Vegetable Garden Grower’s Masterclass is available online. has more than 10 million visitors each year.

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