Butterfly bush (Buddleja/Buddleia) is a genus of hardy flowering plants that produce appealing fragrant flower heads known for attracting butterflies and other insects. Despite being considered invasive by many ecologists, their striking appearance has helped them maintain their popularity in ornamental gardening.

Types and Varieties of Butterfly Bush
1. ‘Black Knight’ Produces relatively shorter, and one of the darkest shades of flowerheads, with the plants growing up to 15 feet in height Hardiness Zone: 5 to 9	2. ‘Purple Haze’ Short bushy plants of 3-4 feet, these are suitable for hedges, ground covers, and indoor planting Hardiness Zone: 5 to 9
3. ‘Miss Molly’ Comparatively non-invasive in nature, making it more suitable for ornamental gardening Hardiness Zone: 5 to 9	4. ‘Blue Heaven’ With its stunning blue flowers and silver foliage, this is one of the most attractive varieties, growing around 2-3 feet Hardiness Zone: 5 to 9
5. ‘Purple Prince’ Produces orange-blue flowers later in summer, suitable for landscaping, growing up to around 12 feet when mature Hardiness Zone: 4b	6. ‘Orange Sceptre’ Drought-tolerant and ever-flowering, this variety grows up to 6-7 feet but has a relatively slow growth rate. Hardiness Zone: 8 to 11
7. ‘Kaleidoscope’/ ‘Rainbow’/ ‘Bi-color Butterfly Bush’ The first butterfly bush variety to produce multi-colored blossoms of lavender, yellow, and orange, it is quite tolerant of drought and heat Hardiness Zone: 5 to 9	8. ‘Pugster Blue’ A dwarf variety (2-3 feet), it has a compact appearance with sturdy branches that can survive cold weathers better than most other short varieties; considered non-invasive Hardiness Zone: 5 to 9
9. ‘Blue Chip’ A miniature, non-invasive butterfly bush, it is a hardy plant with a fast growth rate Hardiness Zone: 5 to 9	10. Buddleia × Weyeriana ‘Honeycomb’ A taller variety, growing up to 12 feet, it is one of the butterfly bushes less tolerant to winter Hardiness Zone: 5 to 9
11. ‘Evil Ways’ Striking plants with golden leaves and dark gorgeous flowerheads. Hardiness Zone: 5 to 9	12. ‘Miss Violet’ Another non-invasive option like all the ‘miss’ varieties, suitable for garden borders,  it produces closely-packed thin, long flowerheads Hardiness Zone: 5 to 9
13. ‘Petite Snow’ Grows fast, attaining heights of around 4-6 feet at maturity, the compact tiny white flowers are perfect for cuttings Hardiness Zone: 5 to 9	14.‘Lavender Veil’ Hardy plants with high watering needs; produces attractive thick lavender flowers Hardiness Zone: 5 to 10
15. ‘White Profusion’ Growing around 8 feet tall, producing long pure white flowerheads, these look good when planted with bright colored flowers Hardiness Zone: 5 to 9	16. ‘Asian Moon Butterfly Bush’ Growing around 5-7 feet in both height and width, it is a good choice for mixed borders due to its non-invasive, hardy nature Hardiness Zone: 5 to 9
17. ‘Nanho Blue’ Can reach up to 10-12 feet in height, mauve flowers are suitable for cuttings Hardiness Zone: 5 to 9	18. ‘Golden Glow’ With striking yellow-orange fragrant flowers, these 5-6 feet high plants are suitable for large gardens but do not survive in wet, cold conditions Hardiness Zone: 5 to 9
19. ‘CranRazz’ Eight-inch flowerheads blooming around fall-summer, these plants are relatively shorter (5-6 feet), and suitable for growing in containers Hardiness Zone: 5 to 9	20. ‘Magenta Munchkin’ Growing about 2-3 feet in height, and 4 feet in width, a good option for borders Hardiness Zone: 5 to 10
21.‘Royal Red’ Growing around 6 feet high, its branches tend to spread around, giving the plant a fuller appearance Hardiness Zone: 5 to 9	22. ‘Peacock’ A relatively new variety, 4-5 feet high when mature, it is  ideal for mixed borders and small gardens, also suitable to be grown in containers Hardiness Zone: 5 to 9
23. ‘Pink Delight’ Dense shrubs suitable for hedges, these grow about 8 feet high, with bubblegum pink flowers Hardiness Zone: 5 to 9	24. ‘Dark Dynasty’ Dense, 2-3 feet tall shrubs with a somewhat rounded appearance, suitable for mixed garden hedges, flowers suitable for cuttings Hardiness Zone: 4b
25. ‘Miss Ruby’ One of the shorter varieties (4-5 feet), these are are non-invasive, with the flowers being suitable for cutting Hardiness Zone: 5 to 9	26. ‘Blueberry Cobbler’ Around 4-6 feet tall, the non-invasive variety with a rapid growth rate, it is suitable for sunny locations in gardens Hardiness Zone: 5 to 9
27. ‘Adonis Blue’ An English butterfly bush variety, it grows around 4 feet high and 5 feet wide, producing dark blue flowerheads Hardiness Zone: 5 to 9	28. ‘Yellow Buddleia’ Fast-growing plants, reaching up to 8 feet in height, producing bright yellow flowers Hardiness Zone: 5 to 9
29. ‘Tutti Frutti’ A small variety, it works well as ground cover, blooming around late summer Hardiness Zone: 5 to 9	30. Orange Ball Butterfly Bush (Buddleja globosa) Another popular species of Buddleja, it produces orange ball-shaped flower clusters Hardiness Zone: 5-9
31. ‘Buzz Sky Blue’ (dwarf variety) Rather short, bushy plants growing about 4-5 feet tall, these are suitable for small gardens and indoor planting Hardiness Zone: 5 to 9	32. Wooly Butterfly Bush (Buddleja marrubiifolia) Yet another species in the genus, it produces globule-shaped flowerheads, about ½ inch in diameter, with the plant growing up to 5 feet Hardiness Zone: 7

Points to Consider Before Introducing Butterfly Bush

As mentioned above, they appear in invasive plant lists in many states of US, so check with the authorities before picking any variety. The seedless or sterile types like ‘Miss Ruby’, ‘Asian Moon’, and ‘Blue Chip’ are often preferred for this reason.

Another thing worth knowing is that despite their name, they are not beneficial to butterflies in any way apart from offering their sweet nectar. None of the butterfly bushes serve even as a secondary host plant for any caterpillar.

Despite being perennials, most cultivars die in winter, especially in the Northern regions, with the roots growing fresh stems again the next season. So, they are not suitable if you want a low-maintenance evergreen garden.

How to Grow, and Take Care of a Butterfly Bush Plant

Generally hardy in nature, they do not take too much hard work and can get established in almost any type of well-drained soil. These plants have a fibrous root system, instead of a taproot, which means the roots get their nutrients from the upper layers of soil.

How to Plant

1. Prepare the soil by loosening it, and apply some compost
2. Dig a hole that is twice as deep and wide as the root ball of the plant
3. Remove the plant from the container it came in, and gently ruffle the roots to free them up a little, and put the plant in the hole (the crown should be on the same level with the soil surface)
4. When transplanting multiple plants in a row, keep them 5-10 feet apart from each other; dwarf varieties may be planted a little closer together
5. Water thoroughly to help the plant get settled

Where to plant them: Any sunny spot in your garden that remains reasonably dry throughout the year

Best time to plant: Spring, or fall (just before the frost)

When do they bloom: From summer to autumn

It is possible to start a butterfly bush from branch cuttings, but it is more common to get a small plant from nursery so you can be sure that it will not turn invasive. Propagating from seeds is often avoided for the same reason.

Transplanting

Other Care Requirements

Watering

During the first growing season, make sure to keep the soil around the roots thoroughly moist, but not waterlogged. You don’t have to water it every day, especially during the rainy season. Just water well when the soil seems dry.

Once established, all the varieties are pretty tolerant to draught, and will only need watering during particularly long dry spells. Check your plant for signs like wilted leaves as it indicates a need for water.

Sunlight

Although it can survive and grow in partial shade, it does best in full sun, producing fuller, vibrant flowers. If you are growing your butterfly bush in a pot, keep it at a spot that receives a lot of direct sunlight.

Fertilization

They do not require constant fertilization. In fact, some gardeners find that fertilizing too much may actually affect the leaves and flower production. If you amend the soil properly with compost before planting, further application of 2-3 inch of compost around the plant roots just once every spring will be enough. In addition to feeding the plant, compost also helps the soil hold moisture for longer by enhancing the organic matter in it.

Avoid fertilizing for about two months before the beginning of frost to prepare the plant for winter. It makes sure there are no new growths that can get damaged by the cold when the plant goes dormant.

Mulching

When done once every spring, it helps with weed control. In northern climates, applying about a 6-inch mulch layer can help the roots survive the harsh winter.

Pruning and Deadheading

Though quite low-maintenance otherwise, these plants do need an annual trimming and regular deadheading (snipping off any browning flower clusters in fall to encourage more flower-growth, and prevent self-seeding in fertile varieties).

In warmer climates, prune the plant once early in spring to remove any broken or winter-damaged branches.

In northern regions, butterfly bushes die back to the ground in winter, so wait till late in spring to make sure if it is dead. If it does not come back, trim it down to just around 6 inches from the ground. Make sure not to prune at the beginning of winter, as at that time, the stems become hollow, and pruning makes water accumulate within the branches, eventually freezing them from the inside.

Butterfly Bush in Ornamental Gardening: Uses and Benefits

Though some varieties can grow up to 12 feet in height, there are plenty of dwarf butterfly bush varieties that stay within 3-4 feet, producing equally attractive, and fragrant flowers. Most of these are also sterile, solving the weed problem to some extent.

They are quite valuable in ornamental gardening as apart from butterflies, insects and birds like ladybugs and hummingbirds also like these plants. Moreover, they are all deer resistant.

Though they can be planted with other sun-tolerant flowering plants, make sure to keep a 4-5 feet open space around the butterfly bush to permit yourself get close enough to the plant to deadhead them. Overcrowding the area might make it difficult to handle any self-seeding variety. Echinacea or coneflowers seem to do well with butterfly bushes as they have similar natural requirements and the two compliment each other.

Butterfly Bush Problems and Diseases

Problems related to soil quality

Root rot can be a common problem if the plant is made to sit in flooded conditions for long, while too much acidity in the soil can lead to iron deficiency, causing the leaves to turn yellow, with green veins. Avoiding the first problem can be as simple as keeping the soil well-drained, as its fibrous roots already make it less susceptible to root rot compare to deep rooted plants, as long as the soil is maintained properly. The second issue with iron deficiency may need balancing the soil pH with lime and fertilizer.

Fungal, bacterial conditions and bugs

Despite having a good resistance against most bugs, the plant can be susceptible to conditions like downy mildew (fungal disease), and spider mites. Aphids, wasps, and flies may also infest a butterfly bush.

In most cases, keeping a good distance between two plants to keep them from becoming overcrowded, and spraying their leaves with water, and sometimes a liquid insecticide can help get rid of such problems. Though some people find it particularly difficult to get rid of aphids, which might only go away when the plant regrows after a death spell in winter.

Can Butterfly Bush be Poisonous for Pets

According to the University of California, butterfly bush is non-toxic for humans, while the American Society for the Prevention of Cruelty to Animals (ASPCA) shows no evidence of it being poisonous to dogs, cats, and other pets. However, like many other plants, ingesting the flowers and leaves might cause a little stomachache in pets.