17 Butterfly Bush Varieties (Buddleia): Ranked by Hardiness, Size, and Bloom Season
Compare 17 butterfly bush varieties by hardiness zone, size, and bloom season — from classic Black Knight to rare collector species, with invasiveness guidance by state.
Most gardeners pick a butterfly bush for the flower color and end up surprised when it spreads six feet wider than the tag suggested — or when the local nursery stops stocking it because of state restrictions. The genus Buddleja contains over 100 species, and the cultivated forms range from 18-inch sterile ground covers to 15-foot semi-evergreen trees that produce orange ball-shaped flowers unlike anything else in the summer garden.
The 17 varieties below are organized by type, with hardiness zones, mature size, and bloom season for each one. They run from the classics found at every garden center to rare collector species that rarely appear at nurseries. If your state restricts standard butterfly bush — Oregon and Washington have both banned its sale — skip ahead to the sterile series section; several cultivars have earned official exemptions. For planting depth, soil prep, and deadheading technique, see the butterfly bush growing guide.
Butterfly Bush Varieties: Quick-Reference Comparison
The table below summarizes all 17 varieties by zone, size, bloom time, and sterile status. Use it to shortlist your options before reading the individual descriptions.
| Variety | Species / Group | USDA Zones | Mature Size H × W | Bloom Season | Sterile? |
|---|---|---|---|---|---|
| Black Knight | B. davidii | 5–9 | 6–8 ft × 3–5 ft | June–Sept | No |
| White Profusion | B. davidii | 5–9 | 5–6 ft × 5–6 ft | June–Sept | No |
| Royal Red | B. davidii | 5–9 | 5–6 ft × 4–5 ft | June–Sept | No |
| Pink Delight | B. davidii | 5–9 | 5–7 ft × 5–9 ft | June–Sept | No |
| Nanho Blue | B. davidii Nanho | 5–9 | 3–5 ft × 3–5 ft | June–Sept | No |
| Nanho Purple | B. davidii Nanho | 5–9 | 3–5 ft × 3–5 ft | June–Sept | No |
| Lo & Behold ‘Blue Chip Jr’ | Buddleia × hybrid | 5–9 | 18–20 in × 24 in | June–frost | Yes |
| Lo & Behold ‘Ice Chip’ | Buddleia × hybrid | 5–9 | 20 in × 24–36 in | June–frost | Yes |
| Lo & Behold ‘Purple Haze’ | Buddleia × hybrid | 5–9 | 2–3 ft × 3 ft | June–frost | Yes |
| Lo & Behold ‘Pink Micro Chip’ | Buddleia × hybrid | 5–9 | 20 in × 20 in | June–frost | Yes |
| Pugster Blue | Buddleia × hybrid | 5–9 | 2 ft × 2–3 ft | Summer–frost | Yes |
| Miss Molly | Buddleia × hybrid | 5–9 | 4–5 ft × 4–5 ft | June–Sept | Yes |
| Honeycomb | B. × weyeriana | 6–9 | 5–12 ft × 4–8 ft | Early summer–fall | No |
| Fountain Butterfly Bush | B. alternifolia | 5–9 | 8–15 ft × 10–18 ft | Late spring–early summer | Rare spread |
| Orange Ball Tree | B. globosa | 6–9 | 10–15 ft × 8–12 ft | Early summer | No |
| Fallowiana ‘Alba’ | B. fallowiana | 5–9 | 5–8 ft × 8–13 ft | Late summer–fall | Potentially weedy |
| Himalayan Butterfly Bush | B. crispa | 8–9 | 6–10 ft × 6–10 ft | Summer | Rarely invasive |
Classic B. davidii Varieties
Buddleja davidii is the species behind most butterfly bushes sold in the US. Native to central China, it was introduced to Western gardens in the 1890s and has since produced hundreds of named cultivars. These six have the strongest track records — four carry the RHS Award of Garden Merit, and all perform reliably across zones 5–9 [2]. One consistent pattern: in zones 5 and 6, B. davidii frequently dies back to the ground in winter and regrows as a pseudo-perennial, flowering on that year’s new growth. This is not failure — it is the species’ natural adaptation to hard winters, and plants rebound vigorously each spring.
1. Black Knight
The darkest purple butterfly bush in widespread cultivation, ‘Black Knight’ grows 6–8 feet tall with flower panicles reaching up to 18 inches. The blooms are a near-true deep violet with a small yellow eye at the throat, and the color holds through the heat that bleaches lighter purple cultivars. It grows vigorously — count on 3–4 feet of new wood in a single season in zones 7–9, which means hard pruning in late winter is essential to keep it from swamping neighboring plants [2]. RHS Award of Garden Merit holder since 1993. Not well-suited to containers.
2. White Profusion
‘White Profusion’ earns its RHS Award of Garden Merit — received in both 1993 and 2010 — through sheer reliability. It flowers longer and more prolifically than most white-flowered buddlejas, with 12–14-inch panicles opening from midsummer until the first hard frost with regular deadheading. At 5–6 feet tall and equally wide, it works in borders where ‘Black Knight’ would overwhelm. The clean white flowers pair well with deep-purple agastaches, blue salvias, and ornamental grasses, and the fragrance is stronger than most colored cultivars [2].
3. Royal Red
‘Royal Red’ is the benchmark for red-toned butterfly bushes, though its flowers are technically a magenta-purple rather than true red — worth knowing if you’re color-matching. RHS Award of Garden Merit holder, growing 5–6 feet tall by 4–5 feet wide, with dense 10–14-inch panicles. Like all B. davidii, it blooms on new wood, so hard pruning in late winter or early spring produces the most vigorous flowering [2].
4. Pink Delight
‘Pink Delight’ is one of the few butterfly bushes that delivers true pink — not pink-purple, not lilac, but a bright clear pink that holds its color in full sun. RHS Award of Garden Merit since 1993. The plant spreads wide: specimens regularly reach 5–9 feet across, so give it room. The pink color intensifies rather than bleaches in high heat, making it particularly effective in southern gardens. Deer find it unpalatable — a meaningful advantage in rural zones 7–9 [2].
5. Nanho Blue
The Nanho Group is a series of compact, fine-textured B. davidii selections with silvery-gray willowy foliage — visually distinct from standard cultivars. ‘Nanho Blue’ grows 3–5 feet tall and wide, producing mauve-blue flower spikes up to 10 inches long from June through September [9]. In zones 5–6 it often dies back in winter but regrows reliably. The gray-green willowy foliage suits cottage and prairie-style borders. This is not a sterile cultivar — deadhead spent flower clusters promptly to limit self-seeding [9].
6. Nanho Purple
‘Nanho Purple’ mirrors ‘Nanho Blue’ in habit and size but flowers in a cooler lavender-purple. It stays 3–5 feet tall with annual late-winter pruning, or reaches 5–8 feet without it. Flower spikes are 6–8 inches, carried on arching stems that read gracefully from a distance. Effective grown alongside ornamental grasses, where the contrast in texture amplifies both plants. Not sterile — deadhead to prevent self-seeding [2].
Sterile Modern Series: Safe for Restricted States
The Lo & Behold® series emerged from a breeding program at North Carolina State University led by Dr. Dennis Werner. The goal was a butterfly bush that could not spread — achieved by crossing B. davidii with B. lindleyana and B. globosa (via B. × weyeriana ‘Honeycomb’) to produce complex interspecific hybrids with fewer than 2% viable seeds [10]. The first cultivar, ‘Blue Chip’, debuted commercially in 2007. Several cultivars from this group, along with the Miss series, are now officially approved for sale in Oregon and Washington where standard B. davidii is banned.
7. Lo & Behold ‘Blue Chip Jr’
The smallest blue butterfly bush available, reaching just 18–20 inches tall and 24 inches wide — small enough for a 12-inch container. Flowers are a truer blue than the original ‘Blue Chip’, and the plant is fully sterile, producing no viable pollen or seeds [10]. In zones 5–6 it dies back to the ground each winter but regrows reliably from thick roots in spring. One of six cultivars officially approved for sale in Oregon and Washington.
8. Lo & Behold ‘Ice Chip’
‘Ice Chip’ is the ground-cover butterfly bush. It grows only 18–20 inches tall but spreads 24–36 inches wide with a horizontal mounding habit unlike any standard buddleja. Flowers are bright white, and the plant is essentially zero-fertility, never setting viable seed [10]. Use it at the front of a border, spilling over a low wall, or in mass plantings along pathways.
9. Lo & Behold ‘Purple Haze’
The largest cultivar in the Lo & Behold® series at 2–3 feet tall and 3 feet wide. Flowers are a rich royal purple, blooming from June until hard frost without deadheading. Seed-sterile, approved for restricted states, hardy in zones 5–9 — the most versatile choice in the series for gardeners who want a traditional butterfly bush look without invasiveness concerns [10].
10. Lo & Behold ‘Pink Micro Chip’
The most compact pink butterfly bush available at just 20 inches tall and wide. The flowers lack anthers entirely, making the plant completely seed-sterile [10]. Bright clear pink from early summer through frost. The micro-compact size works in window boxes, mixed containers, and border edges where larger shrubs overwhelm.
11. Pugster Blue
Where the Lo & Behold® series emphasizes extreme compactness, the Pugster® series prioritizes hardiness. ‘Pugster Blue’ grows 2 feet tall and 2–3 feet wide, but its signature feature is stem thickness — significantly sturdier than comparable dwarf cultivars, which translates to better winter survival in zone 5 [11]. Flowers are true-blue with a yellow-orange eye, fragrant, and attract butterflies and hummingbirds from midsummer through frost. The National Garden Bureau named Buddleia the 2024 Shrub of the Year, with the Pugster series as a key factor [11].
12. Miss Molly
‘Miss Molly’ produces some of the deepest red flowers in the butterfly bush family — a genuine cherry-red rather than the magenta-purple of ‘Royal Red.’ It grows 4–5 feet tall and equally wide, the largest of the approved sterile cultivars. The Miss series was bred to meet invasive plant regulations and validated at fewer than 2% viable seeds [1]. Approved for sale in Oregon and Washington. If you’re choosing between butterfly bush and a similarly sized summer-blooming shrub, see our butterfly bush vs. lilac comparison.
B. × weyeriana: The Yellow and Orange Group
Buddleja × weyeriana is a hybrid between B. davidii and B. globosa, first raised in England around 1914. Its most distinctive feature is flower color — the only butterfly bush that reliably produces yellow to orange blooms in cultivation. These hybrids are fertile and share the invasiveness concerns of B. davidii. They are also slightly less cold-hardy, rated for zones 6–9 rather than 5–9 [4].
13. Honeycomb
‘Honeycomb’ is the best-known B. × weyeriana cultivar and one of the parent plants used in breeding the Lo & Behold® series. It grows 5–12 feet tall and 4–8 feet wide, producing creamy yellow panicles with orange eyes from early summer through early fall. One critical pruning distinction from B. davidii: it blooms on both old and new wood, so hard pruning in late winter removes this year’s developing flower buds alongside last year’s dead stems. Prune lightly after the first flush in midsummer instead, removing only dead or crossing stems [4].
Rare and Collector Species
These four species look and behave nothing like the B. davidii cultivars most gardeners know. Each blooms at a different time, in a different form, often in colors unavailable anywhere else in the summer garden. Track them down through specialist shrub nurseries and mail-order suppliers — they rarely appear at big-box stores.
14. Fountain Butterfly Bush (B. alternifolia)
The most winter-hardy Buddleja species, surviving to zone 5 as a full-sized shrub without dying back — and the only one that naturally takes a tree form. It can be trained as a single-trunk standard reaching 15 feet. The flowers are completely different from B. davidii: small clusters of fragrant lavender blooms stud long arching stems from late May through June, creating a cascading curtain of color. The critical pruning rule: B. alternifolia blooms on the previous year’s wood. Prune it hard in late winter — like a B. davidii — and you will cut off every flower bud for that year. Prune lightly after flowering in early summer instead, removing no more than one-third of the oldest stems [3]. The alternate leaf arrangement (leaves alternate along the stem rather than opposite, as in B. davidii) is the easiest field ID for this species.
15. Orange Ball Tree (B. globosa)
Nothing in the butterfly bush world looks like B. globosa. Instead of spike-shaped panicles, it produces spherical orange-yellow flower balls — each about 2 cm across — clustered at branch tips in early summer. The RHS has awarded it the Award of Garden Merit and lists it as a Plant for Pollinators, noting strong attraction to bees and butterflies [6]. It is semi-evergreen — holding dark green leathery leaves through mild winters but dropping them in cold snaps. Like B. alternifolia, it blooms on the previous year’s wood: prune after flowering, not in late winter. Hardy in zones 6–9, reaching 10–15 feet tall by 8–12 feet wide at maturity [5].
16. Fallowiana ‘Alba’ (B. fallowiana)
B. fallowiana grows wild in the Himalayas and western China, and it shows — the stems are covered in dense white woolly hair, and the gray-green leaves have a felted texture unlike any other butterfly bush. ‘Alba’ is the hardiest form, rated to zone 5a, producing white flowers with yellow throats from late summer through fall — a different bloom window from any B. davidii cultivar [13]. The silvery woolly foliage is the main attraction in spring and early summer before flowers open. Find it through specialist shrub nurseries; it rarely appears at garden centers.
17. Himalayan Butterfly Bush (B. crispa)
Buddleja crispa is the rarest variety on this list — a Himalayan species with intensely white-woolly stems and fragrant lilac-pink flowers. Hardy only in zones 8–9, but in warm coastal gardens it is extraordinary. Every part of the plant — stems, leaves, and young buds — is covered in dense white hairs, giving it a ghostly silver appearance even before flowers open. The species is a wide botanical cross, entirely distinct from B. davidii, placing it in a different branch of the genus. Source it through specialist shrub collectors or botanical garden plant sales.
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→ View My Garden CalendarThe Invasiveness Question: What to Know Before You Plant
Standard B. davidii is invasive in the Pacific Northwest and increasingly documented in the mid-Atlantic. Oregon and Washington have banned its sale entirely. In Maryland, the species spread from 4 counties in 2019 to 12 counties by 2025, and the state is reviewing its regulatory status for 2026 [7]. North Carolina’s Invasive Plant Council lists it as a severe threat in the mountain and Piedmont regions [2].
The spread mechanism is simple: each flower capsule produces dust-like seeds that disperse by wind and water. A plant can produce 3–15 feet of new growth in a single season and establishes readily along streams, roadsides, and disturbed ground [7]. One ecological nuance most gardening guides skip: adult butterflies do visit the nectar, but butterfly bush leaves provide no nutrition for caterpillars. A garden that replaces native shrubs with butterfly bush may attract adult butterflies while eliminating the larval host plants their caterpillars depend on [7]. For a pollinator planting that supports the full butterfly life cycle, see our flowers that attract bees and butterflies guide.
The sterile series is the practical workaround. To qualify as non-invasive under Oregon’s regulations, a cultivar must demonstrate fewer than 2% viable seeds and must result from a wide cross — breeding between two distinct Buddleja species [12]. The following six cultivars currently hold official non-invasive status and are approved for sale in Oregon and Washington: Miss Molly, Lo & Behold® Blue Chip Jr, Lo & Behold® Pink Micro Chip, Miss Violet, Lo & Behold® Purple Haze, and Miss Ruby [12].
Old Wood vs. New Wood: The Rule That Changes Everything
Most butterfly bushes bloom on new wood — the stems produced in the current growing season. This is why hard pruning in late winter produces the best flowers: it forces vigorous new shoots, each carrying a flower spike. B. davidii, B. fallowiana, and all the sterile modern series follow this pattern.
Three groups break this rule. B. alternifolia and B. globosa bloom exclusively on the previous year’s wood. B. × weyeriana blooms on both old and new wood. Hard-prune B. alternifolia or B. globosa in late winter and you remove every flower bud for that year — a mistake that costs an entire season of flowers. The correct approach is to wait until just after flowering in early summer, then cut back no more than one-third of the oldest stems [3][6].
| Species / Group | Blooms On | When to Prune |
|---|---|---|
| All B. davidii cultivars (Black Knight, White Profusion, Royal Red, Nanho group, etc.) | New wood (current season) | Late winter / early spring |
| Lo & Behold®, Pugster®, Miss series | New wood | Late winter / early spring |
| B. × weyeriana (Honeycomb) | Old + new wood | Light prune after flowering; do not hard prune |
| B. alternifolia (Fountain Butterfly Bush) | Old wood only | After flowering, early summer |
| B. globosa (Orange Ball Tree) | Old wood only | After flowering, early summer |
| B. fallowiana ‘Alba’ | New wood | Late winter / early spring |
| B. crispa (Himalayan) | New wood | Late winter / early spring |
Choosing the Right Butterfly Bush for Your Garden
Three factors drive the decision: available space, your USDA zone, and whether your state has restrictions.
Containers and very small borders (under 2 feet): Lo & Behold® ‘Blue Chip Jr’ (18–20 inches), Lo & Behold® ‘Pink Micro Chip’ (20 inches), Lo & Behold® ‘Ice Chip’ (ground cover). All sterile, all state-approved.
Compact border plants (2–3 feet): Pugster Blue and Lo & Behold® ‘Purple Haze’. In zone 5, Pugster Blue has the edge in winter survival due to its thick stems [11]. Both are sterile.
Mid-border (3–5 feet): Nanho Blue, Nanho Purple, Miss Molly. The Nanho cultivars are not sterile — deadhead regularly. Miss Molly is sterile and state-approved.
Large shrub or specimen (over 5 feet): Black Knight, White Profusion, Royal Red, Pink Delight. All are standard B. davidii — verify your state’s regulations before planting.
Yellow or orange flowers: ‘Honeycomb’ (B. × weyeriana, zones 6–9) is the only readily available option. B. globosa provides unique spherical orange flowers but needs zones 6–9 and specialist sourcing.
Zones 5–6: Expect all B. davidii cultivars to die back in winter. Pugster Blue is the strongest compact performer at zone 5 due to thick stems [11]. For a full-sized cold-hardy shrub that doesn’t die back, B. alternifolia (Fountain Butterfly Bush) is the best choice in this genus.
Restricted states (Oregon, Washington): Choose from the six officially approved sterile cultivars listed in the invasiveness section above. All are compact, all bloom from June through frost, and none set viable seed.
Frequently Asked Questions
What is the most cold-hardy butterfly bush?
Buddleja alternifolia (Fountain Butterfly Bush) is the most winter-hardy species, surviving to zone 5 as a full-sized shrub that does not die back. Among compact sterile cultivars, the Pugster® series has the best zone 5 winter survival due to thick stems. Standard B. davidii cultivars survive zone 5 but typically die back to the ground and regrow each spring.
Are any butterfly bushes truly native to North America?
Buddleja americana is native to parts of the southern US and Mexico, but lacks the ornamental flower spikes of B. davidii and is found only in specialist collections. For a native alternative that supports adult butterflies and caterpillar larvae, consider buttonbush (Cephalanthus occidentalis), New England aster, or Joe-Pye weed — all recommended by the University of Maryland Extension as butterfly-friendly native alternatives [8].
Can I grow butterfly bush in a container?
Yes. Lo & Behold® ‘Blue Chip Jr’ (18–20 inches) and Pugster Blue (2 feet) both work in 12–16-inch containers with well-draining potting mix. Container plants in zones 5–6 should be moved to a sheltered unheated space before hard frost. Standard B. davidii can be grown in large containers (15+ gallons) but grows vigorously and requires annual hard pruning to stay manageable.
Sources
[1] NC State Extension — Buddleja genus overview
[2] NC State Extension — Buddleja davidii
[3] NC State Extension — Buddleja alternifolia
[4] NC State Extension — Buddleja × weyeriana
[5] NC State Extension — Buddleja globosa
[6] Royal Horticultural Society — Buddleja globosa (Orange Ball Tree)
[7] University of Maryland Extension — Butterflybush invasiveness (updated 2025)
[8] University of Maryland Extension — Butterfly Bush
[9] Missouri Botanical Garden — Buddleja davidii ‘Nanho Blue’
[10] Trees and Shrubs Online — Buddleja Lo and Behold Series
[11] Proven Winners — Pugster Blue Butterfly Bush
[12] ButterflyBushes.com — Which Butterfly Bushes Are Not Invasive
[13] NC State Extension — Buddleja fallowiana
Related: Growing Butterfly Bush in Zone 4: Survive the -30°F Winters and Bloom Every Summer
