Buddleias are vigorous growers that remain evergreen in winters with minimum temperatures of 20 degrees. Where winters are more severe they can be deciduous, merely dropping leaves, or herbaceous, freezing completely back to the ground. Phenomenal growth is achieved the next spring, even if they do freeze all the way to the ground. Leaving branches on until spring and mulching over winter are good practices for those in the coldest areas of zone 5.
While flower colors are often referred to as blue, there are no true blue (or red) flowers in the Buddleia genus. Their colors range from very dark purple to pink to pure white. Some hybrids have orange and gold flowers.
Black Night (perhaps the darkest Buddleia davidii) is a very old variety that can easily grow to 15 feet. It has an open structure and slightly shorter flowers than more modern selections .
Twilight is a Mountain Valley Growers’ introduction. It was bred here to be extra drought resistant, to have denser growth, and to have more heat tolerance during blooming. It has a pretty dark purple flower . It tops out at about 10 feet. It also does great under normal garden conditions as long as it gets proper drainage.
Royal Red is a smaller shrub that tops out at about 6 feet. The flowers are a bit shorter than some others and the color is more maroon than red. At about 6 feet, the branches tend to splay out rather than grow upright. It might look untidy to some but we like the weeping habit and so do the birds.
Harlequin is a sport of Royal Red. It has cream and green variegated leaves and maroon flowers. This plant rarely gets over 4 feet here. It may be marginal in a true zone 5 winter so a deep mulch is recommended. Branches sometimes revert back to all green but these are easily removed.
Dwarf Blue, also known as Nanho Blue, was, at first introduction, thought to be a smaller bush. However, the bush can get up to 12 feet tall. The lilac flowers are smaller but very prolific.
Pink Delight is a tall, stately shrub with long bubblegum pink flowers. It gets about 8 feet tall and grows densely which makes it a good choice for a hedge.
White Profusion has long, pure white flowers and reaches about 8 feet tall. It looks great planted with red flowers like Maraschino Cherry Salvia.
Evil Ways is a golden leaved beauty. Perfect for darker spots in the garden. Gorgeous flower just like Royal Red.
Sungold is a Buddleia hybrid (Buddleia x weyeriana) that is a dense, well-formed shrub that reaches about 8 feet. It is loaded with lots of golden pom-pom like flowers. It may need to be mulched in the coldest zone 5 winters.
BiColor is a Buddleia hybrid (Buddleia x weyeriana) that grows a little slower and may be shorter than other B. davidii’s. The flowers are an intriguing mix of pink and gold. It may need to be mulched in the coldest zone 5 winters.
Fountain Butterfly Bush (Buddleia alternifolia) has graceful, drooping branches that are covered in the spring with sprays of lilac flowers that give the whole plant a water fall effect.
Chinese Weeping Butterfly Bush is perhaps the most beautiful of all butterfly bushes. It’s long weeping flowers are graceful and add architectural interest to the garden.
- Butterfly Bush Pruning
- Butterfly bush, hydrangea — how to prune out winter damage
- Avoiding Butterfly Bush Winter Kill: Learn How To Overwinter A Butterfly Bush
- Butterfly Bush Winter Kill
- Do I Prune My Butterfly Bush for Winter?
- How to Overwinter a Butterfly Bush Indoors
- Growing Butterfly Bushes in the Home Landscape
Butterfly Bush Pruning
Pruning butterfly bushes is an integral part of maintaining these beautiful flowering shrubs. It is fairly easy to prune a butterfly bush, as they are very tough plants. Butterfly bushes will survive just about any level of pruning they are given at any time of the year. There are, however, pruning techniques that will assure faster growth and better blooms.
When the butterfly bush goes dormant, during the winter of zones five and six, is when the most pruning should take place. During this time pruning butterfly bushes should be done all the way to the ground. This will usually take place some time after the first frost, when the above ground parts of the bush appear dead. In zones eight and up, the butterfly bush will be evergreen, and can be pruned to the ground at any time.
Pruning butterfly bushes in the spring will not kill the bushes. At worst, all that will happen is that the flowers will not appear as soon, because they need to re-sprout. Because butterfly bushes grow so fast, the blooms should reappear within a few weeks. In colder regions of zone five, a three to six inch layer of mulch should be applied to the butterfly bush after winter cutting in order to help protect the shrub for the coming winter. There is really no wrong way to go about pruning butterfly bushes. The shrubs are very stable and can take a good deal of stress without any significant side effects. Butterfly bushes will generally flower of new wood, so cutting them to the ground in winter is often times necessary for the plants to bloom.
Butterfly bush, hydrangea — how to prune out winter damage
As late-blooming shrubs and perennials are finally beginning to green up, many homeowners are just now seeing the full effects of our fiercely cold and long winter.
Hydrangea and butterfly bush (Buddleia) seem particularly hard hit, with many of the shrubs having died back right to the ground. Where you would normally see lots of new green growth all over the upper and lower branches and stems, there is none. The only signs of green growth are coming from the very base of the plant or even from the roots.
Many of the damaged plants, especially hydrangeas that bloom on last year’s growth, are unlikely to come into flower this year and possibly next year as well.
“We’ve seen this before after a rough winter,” says Amy Albam, community horticulture educator with Cornell University Cooperative Extension of Westchester. “In colder climates, Buddleia acts as an herbaceous perennial. While the plants are relatively drought tolerant, the dry conditions last fall probably didn’t help either, as the plants were not well hydrated before the ground froze.”
Butterfly bush blooms on new wood produced this year, so you may finally get some flower heads, but they will be later than usual because of the cool spring and previous stress from the dry fall, Albam says.
“The only thing to do now is cut out the dead areas and hope it will grow back,” she says.
In general, butterfly bush should be pruned — you can prune them hard, down to 12 to 18 inches from the ground — in early spring when you see the first new growth emerging on the lower stems. Don’t prune them in the fall, when you do the rest of your garden cleanup chores. Besides, their gray-green stems and remaining leaves look gorgeous in winter. (They do self-seed; if you worry about them becoming invasive, cut off the seed heads in fall.)
You may be tempted to fertilize your damaged plants to help them come back to life, but don’t, Albam says. “Fertilizer is likely to do more harm than good, especially given the stress the plants have endured. Buddleia normally grows happily in waste areas with low fertility.”
“We’ve seen winter injury on many evergreen plants as well,” she adds.
Keep an eye (and hose) on all of these damaged plants throughout the summer because they will continue to be under stress when we inevitably get hot weather and prolonged periods without rain.
Avoiding Butterfly Bush Winter Kill: Learn How To Overwinter A Butterfly Bush
Butterfly bush is very cold hardy and can withstand light freezing temperatures. Even in cold regions, the plant is often killed to the ground but the roots can stay alive and the plant will re-sprout in spring when soil temperatures warm up. Severe and sustained freezes will kill the roots and plant in United States Department of Agriculture zone 4 and below. If you are concerned about butterfly bush winter kill in your region, take some tips on how to save the plant. There are several steps to preparing butterfly bushes for winter and saving these colorful plants.
Butterfly Bush Winter Kill
Even in a temperate zone, there are chores to do to help plants withstand winter storms and weather. Butterfly bush winter protection in warmer climates usually just amounts to some extra mulch around the root zone. We’ve been asked, “do I prune my butterfly bush for winter and what other preparation should I take?” The extent of overwintering preparation depends upon the severity of the weather the plant will experience.
Buddleia lose their leaves in fall in most areas. This is a common occurrence and may make it appear the plant is dead but new leaves will arrive in spring. In
zones 4 to 6, the tops of the plant may die back and no new growth will come from this area, but not to worry.
In spring, new growth will rejuvenate from the base of the plant. Prune off the dead stems to retain an attractive appearance in late winter to early spring. Container grown plants are at the most risk of damage from winter chill. Move potted butterfly bush indoors or to a sheltered area to protect the roots from the cold. Alternately, dig a deep hole and put the plant, pot and all, into the soil. Unearth it when soil temperatures warm up in spring.
Do I Prune My Butterfly Bush for Winter?
Pruning butterfly bushes annually actually enhances the flower display. Buddleia produces blooms from new growth, so pruning needs to be done before new growth appears in spring. In areas with ice storms and severe weather that can break plant material and cause damage to the structure, butterfly bush can be severely pruned and it will not adversely affect the flower display.
Removing errant stems and growth will help prevent more acute damage from winter weather and is a sensible way of preparing butterfly bushes for winter in any region. Place a 3- to 4-inch layer of mulch around the root zone as further butterfly bush winter protection. It will act as a blanket and keep roots from freezing.
How to Overwinter a Butterfly Bush Indoors
It is common to move tender plants inside to protect them from cold weather. Buddleia grown in cold zones should be dug up and placed in potting soil in containers. Do this in late summer to early fall so the plant has a chance to adjust to its new situation.
Water the plant regularly but slowly diminish the amount of moisture you give the plant a couple weeks before the date of your first frost. This will allow the plant to experience dormancy, a period when the plant is not actively growing and is, therefore, not as susceptible to shock and site changes.
Move the container to a location that is frost free but cool. Continue to water sparingly throughout winter. Gradually reintroduce the plant to the outdoors when soil temperatures warm up. Replant the butterfly bush in prepared soil in the ground after all danger of frost has passed.
Growing Butterfly Bushes in the Home Landscape
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).
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.
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.
Insects and diseases are generally not major problems in Iowa. The biggest threat to the butterfly bush is our harsh winter weather.
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.
- ‘Charming’ – flowers are pink with orange throats, borne on 6 to 8 inch-long panicles.
- ‘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.
- ‘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.
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. Butterfly bushes are available in garden centers and mail-order catalogs. Mail-order sources include:
|Bluestone Perennials7211 Middle Ridge Road Madison, Ohio 44057||Plant Delights Nursery9241 Sauls Road Raleigh, NC 27603||Wayside Gardens1 Garden Lane Hodges, SC 29695|
A colorful brochure, “Common Butterflies of Iowa”, is available for $1.00. If your local County Extension office does not have this publication, you may order it from: Extension Distribution Center Printing and Publications Building Iowa State University Ames, IA 50011
This article originally appeared in the February 22, 2002 issue, pp. 17-18.