The butterfly bush has large, showy flowers that attract pollinators such as butterflies

Source: http://gardencoachpictures.wordpress.com/tag/butterfly-bush/

Hummingbirds are also attracted to the fragrant flowers of the butterfly bush

Buddleia davidii

Description: 

Buddleia davidii, also known as summer lilac, butterfly bush, or orange eye is flowering plant in the family Scrophulariaceae. It is characterized as a medium to large deciduous shrub, reaching heights of up to fifteen feet and a width of about eight feet at full maturity. Native to China and Japan, it is commonly used as an ornamental plant and growers are attracted to its beautiful fragrant flowers that attract a variety of pollinators, including birds such as hummingbirds and butterflies. The flowers bloom in the summer and fall in a variety of colors including pink, rose, blue, violet, red, white and yellow. The honey-scented inflorescences are terminal panicles and the flowers are perfect (having both male and female parts). The leaves are silver to green and variegated.

The butterfly bush thrives in full sun and is characterized as a zone 5-10 plant. It is fairly easy to grow and growers are attracted to it for several reasons including its drought resistance and deer resistance. There are approximately 180 cultivars and numerous hybrid varieties. Several countries in temperate regions, including the United Kingdom and New Zealand, have classified butterfly bush as an invasive species (www.wikipedia.org). It is important to check local restrictions before planting butterfly bush to make sure it is not an invasive species to your region.

The shrub is fairly easy to care for, producing new shoots in the presence of full sun; it is well-tolerant to heat, humidity, drought, and average or poor soils. Butterfly bush is also easy to propagate. Three commonly used methods for propagation are by seed, cutting and division. Generally, it is not propagated by tissue culture or leaf cutting because other methods are easier and more affordable.

Important notes about cuttings:

• Be sure that the tool you are using to take cuttings is sharp and clean.
• Make sure that any propagation container is sterilized and soil media is clean.
• Pinching off the apical tip of a cutting can promote bushier plants.
• Sterilize propagating tool with household bleach or Clorox
• Taking cuttings on a diagonal cut will promote nutrient absorption and root production.
• Choose healthy plant material to take cuttings from without any visible signs of pests, stress, or disease.

Propagation Methods:

Seed:

Butterfly bush can be propagated by seed rather easily, but not as easy as with cuttings. The seeds need to be pre-chilled for up to four weeks prior to planting and can take several months to germinate once in the soil. It is important to sow the seeds close to the surface of the soil because they require a lot of sun. Once the seeds are sown, keep them moist. If you are sowing seeds in a pack, be sure the medium is well-drained and kept moist. Once the seedlings have established roots and are about six to ten inches in height, they may be transplanted. Unlike propagation by cuttings, seed propagation does not preserve genetic uniformity. This can be problematic because the seeds may not grow into superior plants.

Division:

Another common method to propagate butterfly bush is by division. This can be done by carefully digging up a mature bush and separating the roots by hand or dividing the plant with a spade shovel. Be sure that each division has about three stems. The divided bush can be placed in containers or transplanted to suitable areas in the landscape. Once transplanted, be sure to keep the soil moist and fertilizer can be applied to enhance growth.

Cutting:

Propagation by cuttings is the easiest and most widely-used method for butterfly bush. One of the greatest benefits of propagating by cuttings from the selected bush of optimum health ensures that the cuttings will maintain that genetic uniformity. Either hardwood or softwood cuttings can be propagated, but softwood cuttings are easier to root. For softwood propagation, simply take cuttings of the new, succulent growth in the spring or early summer, before the bush blooms in mid-late summer. Using a sharp pair of pruners or knife, make cuttings atleast three inches long and remove the bottom-most leaves and any buds or flowers. Removing buds and flowers allows the cutting to focus its energy on root production.

The bottom end of the cutting can be placed in some type of rooting hormone to enhance its production before planting in the soil media. (Common rooting hormones are Dip-N-Grow and Hormodin) Hartmann & Kester recommend 8,000 ppm of IBA (Plant Propagation, p. 782). Stick cuttings about an inch deep into moist, peaty sand or potting soil and keep moist. Give about 2-3 inches between each cutting to allow for root formation. To ensure that the cuttings are sturdy in the soil, gently pack the surrounding media around the cutting to keep it in place. Place the cuttings out of direct sunlight and maintain warm (approximately 70 degrees Fahrenheit), humid conditions (80-100% humidity). If you do not have a controlled environment to raise the humidity, sufficient misting will keep the humidity high. Roots should begin to develop within a few weeks. Hardwood cuttings of butterfly bush can be taken in the Fall using the same procedures described above for softwood cuttings.

After the plant is well-rooted, you can begin to harden it off by reducing humidity and introducing greater amounts of sunlight to prepare it for transplant in the field.

A picture of a softwood cutting (Source: www.mastergardeners-rc.org)

A video tutorial on propagating Butterfly Bush by softwood cuttings:
https://www.youtube.com/watch?v=IqI0Hf22t6Q

Planting Instructions:

When the seedling or cutting has been sufficiently hardened off and there has been adequate root formation, plant in the field in the spring or fall. Allow five to ten feet between the plantings to allow room for growth into mature bushes of typical widths of eight feet. Before planting, prepare the garden bed with a garden fork or tiller to loosen up any compacted soil, allowing for roots to grow easier and minimizing transplant shock. Be sure to loosen the soil to a depth of twelve to fifteen inches and mix in a two to four inch layer of compost. The organic matter in compost provides many benefits to soil including nutrients, high CEC, pH buffering capacity, water retention and improved soil structure. Dig a hole in the garden bed twice the diameter of the container that the plant is in. Carefully remove the plant from the container and place it in the hole so that the top of the root ball is level with the soil surface. Gently fill in the space around the root ball and firm the soil around the newly transplanted field plant. Finally, water thoroughly.

Care Instructions:  

• When the bush is in its active growth stage, water freely. When it is not actively growing, water sparingly.
• If rainfall in the summertime is less than 1 inch per week, water the plant.
• Avoid fertilizing the butterfly bush. It typically does not require any nutrient amendments for growth and fertilizers can stimulate leaf growth over flower production
• Remove spent flower spikes to stimulate the development of new shoots and flower buds
• Each spring, incorporate a thin layer of compost and mulch to the soil around the butterfly bush for enhanced nutrient and water absorption and to control weeds
• In northern climates, apply a layer of mulch about six inches deep around the trunk of the butterfly bush before the onset of winter for insulation from the cold
• In northern climates, the butterfly bush behaves as an an herbaceous perennial and will die back to the roots in cold winters
• In warm climates, the butterfly bush will grow into a tree with peeling bark
• Buddleias are commonly late to break dormancy; do not be concerned if is late to bloom in the spring
• The bush typically blooms abundantly even in its first year of growth
• Butterfly bush blooms on new wood and severe pruning can promote abundant growth of new wood from which flower can grow
• Even if there is no die-back of the bush in the winter, cutting them back to the ground can stimulate growth

(www.almanac.com)

References: 

“Buddleja Davidii.” Wikipedia. Wikimedia Foundation, 22 Feb. 2014. Web. 26 Feb. 2014.