Kathryn Fontenot, Holzapfel, Alessandro
Strawflowers in a garden. Photo by Kathryn Fontenot
The strawflower (Bracteantha bracteata) Raspberry Rose is a beautiful species, known for its vibrant raspberry rose-colored blooms and the papery texture of its petals. The petals feel stiff and bristly even when on the plant. Strawflower is native to Australia. It is a member of the Asteraceae family. This family includes lettuce, daisies, sunflowers and coneflowers. It was originally used by indigenous people for medicinal purposes, likely treating burns, skin conditions and respiratory disorders. The strawflower’s ability to thrive in various soil types, including sandy, loamy and clay soils, makes it an adaptable plant for different garden settings. These flowers are drought-tolerant and prefer well-drained soil, indicating their suitability for xeriscaping and low-water garden designs. Strawflower made its way to Europe in the late 18th century, during the era of Australian botanical exploration, and became highly admired for dried flower crafts, especially in the Victorian era. Today, it’s celebrated worldwide for its resilience, beauty and low maintenance needs with ongoing research exploring its potential therapeutic applications.
In Louisiana, strawflower is an ideal spring-planted cut flower. We recommend transplanting these flowers. The seed should be sown four to six weeks before the last frost. For optimum germination, leave the seed uncovered to receive light. We recommend starting seed in 50-96 count trays. After the last frost has passed, harden off the seedlings by placing them outdoors but out of direct sunlight for three to seven days. Strawflowers prefer full sun and soil with good drainage. Transplants should be spaced 12 inches apart in a single drill down the center of the row. Prior to planting, apply a complete fertilizer such as 13-13-13. Fertilizer was applied at a rate of 300 pounds of 13-13-13 per acre in the 2023 trails. Once plants have established, about three weeks after planting, we recommend fertigating weekly with nitrogen fertilizer such as calcium nitrate at a light rate. Raspberry Rose strawflowers grew very quickly in the 2023 LSU AgCenter trials. We recommended trellising these plants. The research team noted that Raspberry Rose strawflower stems become heavy and easily break at the growing point causing the flowers to fall onto their sides, or worse, suffer from broken stems. Soils vary throughout the state and therefore making exact fertilizer and exact irrigation recommendations is difficult. We do recommend using drip irrigation with emitters set no further apart than 12 inches. Drip irrigation maintains soil moisture and is not meant to take completely dry soil and replenish all water. Therefore, we recommend daily irrigation simply to maintain a moist but not saturated soil. Overhead irrigation is not recommended as it enhances disease probability especially in rainy years. To prevent weeds, a white plastic mulch was applied to the row prior to transplanting and after fertilizer applications. This practice is recommended as cultivation may further damage the stems that break easily. Herbicides are effective in weed control between the plots. Herbicides containing the active ingredients trifluralin, sethoxydim, or fluazifop-p-butyl would be acceptable in row middles.
2023 LSU AgCenter spring cut flower trial Raspberry Rose strawflower data
|Average Number of Stems per Plant on the First Harvest||7.4 stems|
|Average Stem Length||23 inches|
|Average Number of Flowers per Stem||4.4 flowers|
|Average Flower Width||2.7 cm|
Data collected from five random plants per plot, four plots planted in a randomized complete design with 10 plants per plot, for a total of 20 plants collected for data analysis.
The primary pests observed in the LSU AgCenter plots were snails and slugs. Iron phosphate bait products can attract snails and slugs with their smell. These products can be applied along the row middles and are most effective when applied in the evening. Avoid applying these baits before rain or early in the day. Other snail and slug baits contain the active ingredient metaldehyde. This active ingredient is known to be toxic to dogs, affecting their nervous system. Therefore, we do not recommend using baits with metaldehyde if you have dogs near your cut flower fields or if you operate you-pick fields and allow customers to bring animals.
A second insect pest in the spring strawflower crop was the cucumber beetle (Diabrotica undecimpunctata howardi). We found the beetles chewing on the foliage. However, the damage incurred in the spring 2023 planting did not reach an economic threshold. Therefore, we chose not to spray the flowers since they do attract pollinators. Biological control methods can be employed if cucumber beetles become a problem. Kaur Gill et al., 2020, recommends deploying natural enemies such as tachinid flies, soldier beetles and entomopathogenic nematodes. Cultural practices such as keeping cucurbit, beans and corn crops away from these flowers also help reduce populations. Organic control methods include using kaolin clay and spinosad products. Make sure not to spray spinosad when the plants are near or during bloom.
To obtain optimal yields and to maintain a neat and tidy appearance, Raspberry Rose strawflower blooms should be kept harvested or deadheaded. The Raspberry Rose strawflower can be harvested when two to three layers of petals have unfolded but before flowers fully open. Mature petal color varies from light peach to deep raspberry pink. The flowers look great from closed bud through dried color fade stages for bouquets. However, try to harvest before too many of the flowers on the stem are fully open as these buds tend to close back up at night and shatter easily. Lower stems tend to break at the joint. Harvest these first. During harvest, bring buckets of water with fresh flower food solution to store flowers between the field and cooler. Multiple trips during the harvest to a cooler or air-conditioned facility may be necessary to extend vase life. Post-harvest storage in a cooler will extend vase life; the ideal cooler temperature for strawflowers is 35-40 F (2-4 C). Typical vase life for strawflower ranges from seven to 10 days at an optimal storage temperature of 70-75 F (21-24 C). Raspberry Rose is an excellent variety for spring cut flower production in Louisiana, yielding thick long high-quality stems with multiple booms per stem. Strawflowers are an excellent choice for fresh cut flower displays and for creating dried flower arrangements and crafts.
The tall, bold blooms on the Raspberry Rose strawflower can form beautiful bouquets on their own or paired with other flowers.
To create the simple bouquet featured:
Photo by Allison Huddleston
Jersey Friendly Yards. No date. Bracteantha bracteata. https://www.jerseyyards.org/plant/bracteantha-brac... accessed on June 20, 2023.
Gast, Karen L.B. “Postharvest Handling of Fresh Cut Flowers and Plant Material.” Kansas State University Cooperative Extension Service. 1997. https://ag.umass.edu/sites/agcenter/files/pdf-doc-...
Johnny’s Selected Seeds. 2023. Sunny Ball. https://www.johnnyseeds.com/flowers/matricaria/sun... accessed on June 20, 2023.
Kaur Gill, H., G. Goyal, J. Gillett-Kaufman. University of Florida IFAS. 2020. Featured Creatures. spotted cucumber beetle - Diabrotica undecimpunctata howardi Barber (ufl.edu) accessed on June 20, 2023.
Kathryn Fontenot, Associate Professor, School of Plant, Environmental and Soil Sciences
Allison Huddleston, ASPIRE Intern, School of Plant, Environmental and Soil Sciences
Alessandro Holzapfel, Extension Associate, School of Plant, Environmental and Soil Sciences
Daniel Leiva, Graduate Student, School of Plant, Environmental and Soil Sciences
Kirill Rozhentsev, Student Worker, School of Plant, Environmental and Soil Sciences
The “Raspberry Rose” variety range from a pale yellow to pink, to orange and deep raspberry when ready to harvest. Photos by Kathryn Fontenot
These plants are ready to harvest.
Space strawflowers at least 12 inches apart in a single row. As plants mature, they will fill in this space. Disease pressure will intensify with closer planting.
Trellis strawflowers early in the season to prevent stems from breaking and leaning over.
Strawflowers in the fully open, partially open and bud phases of bloom.
Strawflowers with dark brown centers should be removed. Harvest stems when the majority of blooms are in a partially open phase of bloom.