May 2006

Buddleia davidii ‘Peacock’ By Paul Pilon

Butterfly bush is a popular plant used to attract butterflies and hummingbirds into gardens. Buddleia davidii 'Peacock', also known as 'Peakeep', was bred by Elizabeth Keep of East Malling, England, and is marketed by Proven Winners under the ColorChoice brand of flowering shrubs. 'Peacock' offers several desirable characteristics for today's commercial growers, landscapers and gardeners. It has a compact growth habit — reaching only 4-5 ft. in height at maturity — and large, fragrant, 12- to 14-inch, rich-pink flower spikes.

The compact and tidy appearance of 'Peacock' lends itself to smaller gardens, mixed borders and container production. It is a prolific bloomer, producing flowers from mid-summer until frost. In many parts of the country it is produced and used as a shrub while in the North it is often treated as a perennial. 'Peacock' is fast growing and maintains its desirable plant habit throughout the growing season. Landscapers and gardeners use buddleia in sunny locations throughout USDA Hardiness Zones 5-10.

This is one example of how traditional nursery plants are becoming "perennialized." Many perennial producers have grown various buddleia cultivars for years, but with new cultivars and strong marketing programs backing them, many more perennial growers will be adding this shrub and others to their production plans.

Propagation

Buddleia cultivars are vegetatively propagated by soft wood tip cuttings. 'Peacock' is not patented, but it does require a license to be propagated, as do all of the plants that fall under the Proven Winners ColorChoice brand. Self-propagation is strictly prohibited.

Cuttings can be successfully rooted by sticking them directly into a well-drained growing medium. Dipping unrooted cuttings into rooting compounds is not necessary as 'Peacock' will root well without them. Place the cuttings under a low misting regime for about the first week of propagation. Increasing the misting interval (number of mists per day) or extending the number of days misting is provided will usually result in some plant losses. The average rooting time is 3-4 weeks with soil temperatures of 68-74¼ F. For best results, air temperature during rooting should be maintained above 60¼ F and below 80¼ F.

Production

For container production, 'Peacock' is most suitable for production in 1-gal. or larger containers. When growing 1-gal. pots, ç generally plant one plug per container. For larger container sizes, such as 2-gal. containers, planting multiple plug cells per pot may be appropriate. Buddleia performs best when it is grown in a moist, well-drained medium with good water-holding capacity. The plugs should be planted so the original soil line of the plug is even with or just below the surface of the new container's growing medium.

Many growers have found it beneficial to pinch butterfly bush prior to or shortly after planting in the final container. This is generally a soft pinch, only removing the growing point of the plant and leaving 4-6 leaves on each branch. Pinching increases lateral branching and the total number of flowers produced on each plant. This greatly improves the finished product's quality.

Buddleia is a moderate feeder. During production, the media pH should be maintained between 5.8 and 6.2. Growers using water-soluble fertilizers either feed with a constant liquid fertilization program using rates of 75-100 ppm nitrogen with every irrigation or apply 150-200 ppm of nitrogen as needed. Growers frequently incorporate controlled-release fertilizers into the growing medium prior to planting at a rate equivalent to 1-1/4 lbs. of nitrogen per yard of growing mix.

'Peacock' should be kept evenly moist. When irrigation is necessary, I recommend growers water thoroughly and allow the growing medium to dry slightly between waterings.

When producing buddleia 'Peacock' in containers, it may be necessary to control the plant height. Providing adequate space between plants is the best and most effective method to control plant height during production. Growers commonly spray multiple applications of Sumagic (Valent Corporation) at 5 ppm over their butterfly bushes to reduce stem elongation. It is best to begin PGR applications about two weeks following the pinch and reapply them at 7- to 10-day intervals if additional control is necessary.

Pests And Diseases

There are a number of insects often observed infesting buddleia crops. The most common pests include aphids, leafhoppers, leaf miners, spider mites, thrips and whiteflies. Of these pests, aphids and spider mites are the most prevalent. None of these insects require preventative control strategies. With routine scouting programs, the presence of insects can be detected early and if necessary, the appropriate control strategies can be implemented.

There are no major diseases known to plague this crop at this time. If plants are produced under overly wet conditions, root and crown rots such as Phythium or Phytopthora are more likely to occur. With good watering practices, adequate plant spacing and plenty of air circulation, the occurrence of most diseases can almost be eliminated.

Forcing

Buddleias are obligate long-day plants and will not flower unless grown under long-day conditions. Growers should produce them during times of the year when the photoperiods are naturally long or provide long-day photoperiods during production. After long days are provided, the time to flower largely depends on growing temperatures. For optimum development, growers should produce buddleias at 65-75¼ F. Producing them using lower temperatures results in an increased overall production time.

The amount of time to properly schedule the crop depends on the factors mentioned above — photoperiod and temperature — and also is influenced by pinching. When a 1-gal. crop is not pinched, it can be blooming in as little as seven weeks. If a pinch is conducted at the time of transplant as described above, the time to finish the crop increases to 10 weeks. For larger container sizes, such as 2-gal. containers, that may need two pinches to produce an aesthetic product, a minimum of 12 weeks should be anticipated.

Generally, it will take five weeks from the time of pinching for the plant to reach flowering. Always look ahead at the desired sales date to determine if there is adequate time to pinch plants back and reach flowering on a specific date.

Availability

Buddleia davidii 'Peacock' is marketed under the Proven Winners ColorChoice brand of flowering shrubs. Liners can be obtained only from licensed Proven Winners propagators. Finished containers are widely available from many reputable greenhouses and nurseries across the country.