Perennial Solutions: Gaura lindheimeri Bantam Series
Over the last couple decades, gaura has increased in popularity. However, with its flower power and landscape resiliency, this perennial is often underutilized.Through plant selection and improved genetics, many of today's cultivars offer superior performance over the handful of gaura selections available in the past.
The Bantam series is a recent introduction from Green Fuse Botanicals, which offers a compact plant habit, prolific flowering and cold hardiness to Zone 5. There are currently two colors available in this series: 'Bantam Pink' and 'Bantam White'. Each cultivar produces loads of pink or white flowers, which hover on short, sturdy stems above the dense and neatly rounded foliage.
Its common name, whirling butterflies, refers to the flowers which resemble small charming butterflies whirling around on the slender flower stalks. The Bantam series blooms consistently beginning in midsummer and continues flowering well into the fall. Gaura can be grown across USDA Hardiness Zones 5 to 9 in locations with full sun, and it can tolerate a great deal of heat and humidity once it is established in the landscape.
With its compact size, the Bantam series reaches 12 to 16 inches when in bloom and can be produced in a wide range of container sizes. Additionally, its plant habit and prolific flowering characteristics allow its use as a great companion in mixed containers and patio pots. Gaura Bantam series offers growers, landscapers, and gardeners great versatility and can be easily used for container production, mass plantings and as border plants.
Gaura Bantam series is vegetatively propagated from tip cuttings. Moisten the growing mix or stabilized growing media prior to sticking the unrooted cuttings (URCs). Stick one URC into each cell. Rooting compounds are not necessary but do improve rooting slightly when they are used.
Place the cuttings under a low-misting regime for about the first six to eight days of propagation. When possible, it is usually best to propagate under high humidity levels (90 percent relative humidity) with minimal misting. Gaura are sensitive to over-misting; too much misting or misting for too long will result in disease issues and potentially plant losses. The misting can gradually be reduced as the cuttings develop callus and begin to root. Remove the cuttings from the mist as soon as they are rooted.
At seven to 10 days after sticking, it is beneficial to apply water soluble fertilizers using 75- to 100-ppm nitrogen at each irrigation. The cuttings are usually rooted in less than three weeks with soil temperatures ranging from 68 to 74¡ F. Liners take approximately five to six weeks from sticking to become fully rooted and ready for transplanting.
The Bantam series is best suited for production in one quart to one gallon sized containers. Gaura performs best in a growing mix with both good water-holding characteristics and adequate aeration; peat and bark-based growing mixes will work well. When transplanting, the liners should be planted so the original soil line of the liner is even with the surface of the growing medium of the new container. It is beneficial to soft pinch the plants during the bulking phase to promote lateral branching and improve overall plant quality. Large container sizes may require an additional pinch.
Whirling butterflies perform best when grown with moderate fertility levels. Growers using water soluble fertilizers commonly provide 100- to 125-ppm nitrogen plus micronutrients with each irrigation or 250 ppm as needed. Controlled-release fertilizers can be incorporated into the growing mix before planting using the equivalent of 1.0 pound of elemental nitrogen per cubic yard of growing mix. During production, maintain slightly acidic conditions: pH: 5.5 to 6.2.
Grow gaura under slightly below "average" irrigation regimes. Keep them slightly moist, but not consistently wet during production. When irrigation is necessary, water the plants thoroughly; then allow the growing mix to dry moderately between irrigations.
The Bantam series is naturally compact and should not require height management strategies. It is best to provide adequate spacing between the plants to decrease stem elongation caused by competition as well as to reduce conditions conducive for disease development. If some height control is necessary, the plants can be toned using spray applications of daminozide (B-Nine or Dazide). One to two applications of 2,500 ppm should provide adequate height control.
Insects and Diseases
There are several pests and diseases that attack gaura. Aphids, leaf miners, spider mites and whiteflies are the most prevalent pests. Of these insect pests, aphids occur the most frequently and can often be observed feeding on the growing tips of the newest shoots.
The primary diseases which infect whirling butterflies are Botrytis, Phytopthora, Pythium and Rhizoctonia. Other diseases growers may observe on occasion are downy mildew, powdery mildew and rust. Under cool growing conditions, dark-colored purple spots may develop on the foliage. This spotting is a physiological response (not disease related) and will lessen and disappear with warmer temperatures.
Insects and diseases can be detected with routine crop monitoring; control strategies may not be necessary unless the scouting activities indicate actions should be taken.
Gaura Bantam are first-year flowering perennials and can be easily be grown to flower during the first growing season. In many instances, the plants will bloom before the plants have bulked up and completely filled out the containers. It is usually best to allow some time for bulking prior to allowing them to fully flower. When possible, allow at least four to six weeks for bulking. During the bulking phase, it is recommended to pinch the plants two weeks after they have been potted to promote lateral branching. Bulking can occur during the same growing season they are to be sold or prior to being vernalized (overwintered).
It is not necessary to provide vernalization (a cold treatment) period as they do not require cold for flowering. However, they are cold beneficial plants and will have better quality attributes and more flowers per plant after they have been vernalized. When a cold period is delivered, ensure that at least six weeks of temperatures below 44¡ F are provided.
Gaura are facultative long day plants, which means they will flower under any day length, but will flower faster when long days are provided. Plants grown under shorter day lengths will still flower, but the flowering is delayed and the number of flowers produced is also reduced. To improve plant appearance and flower number, it is beneficial to grow them with high light intensities (4,000 to 9,000 foot-candles). When the day length is naturally short, long day conditions can be created by providing day extension or night interruption lighting.
The amount of time to produce flowering plants after the proper photoperiod is provided is a function of temperature. When growing gaura Bantam series with 24-hour average temperatures of 65¡ F, they will flower in approximately seven weeks while plants grown at 75¡ F will flower in about five weeks. To optimize plant development and produce high-quality plants, I recommend growers force gaura under high light levels with temperatures of 65 to 68¡ F.
Gaura Bantam series is available through H.F. Michell Company (www.michells.com). Contact your sales representative to order liners from one of the rooting stations.
Perennial Solutions: Gaura lindheimeri Bantam Series