From Perennial Solutions Consulting
This exclusive Perennial Solutions Consulting web article discusses methods commercial perennial growers can implement to improve the quality characteristics and over-wintering survival of premium Echinacea cultivars from tissue culture.
By Paul Pilon
For many growers, most of the newer 'premium' Echinacea cultivars from tissue culture are typically smaller then desirable (often a single flower stem and little basal foliage). In most cases, these plants do not produce many basal branches and due to their size and appearance are considered lower quality or may be unacceptable for certain markets or customers. This growing habit is typical of many of these premium cultivars, particularly from plants started by tissue culture during the same growing season the plants are intended to be sold or when liners are planted in the late summer or early fall of the previous year. Additionally, many growers experience significant plant losses with premium Echinacea cultivars after over-wintering them. Significant losses occur regardless of geographic location and over-wintering temperatures (minimal heat and no heat). The exact causes of these losses have not yet been determined. It appears that the majority of the losses occur on plants with a single terminal stem (flower stalk) or with plants that have no or few basal branches present before they go dormant. Main Causes of Poor Bulking and Plant Losses Plants easily turn reproductive shortly after they are placed into production, reducing their ability to develop basal branches and bulk up. Plants with a single flower stem and no basal branches typically do not survive the winter. Plants with no, few or weak basal branches tend to survive poorly following the dormant period. Goals and Methods to Improve Quality and Plant Survival There are several strategies that can be implemented that will both improve the quality characteristics of these crops and reduce overwintering losses. Bulking Until further work in the industry is done to improve the bulking and branching characteristics of many of the premium Echinacea cultivars genetically, it is necessary to change the current production practices of these items to allow growers to produce better branched plugs and fuller appearing containers. To improve bulking (and plant survival following dormancy), it is necessary to produce non-flowering, well-branched plants. This may entail growing finished containers of Echinacea as 12-15 month crops as opposed to 3-4 month or 6-9 month crops as many current practices entail. Liner producers will also need to allow additional production time for sufficient bulking. This additional time combined with lighting and/or the Configure applications described below will greatly improve the appearance and marketability of your premium Echinacea cultivars. These steps will use energy to develop a better plant as opposed to flowers, allow adequate time for bulking up the basal branches (mature enough to overwinter), greatly increase the plants ability to survive the dormant period, and produced higher quality, better branched plants for late spring and summer sales. Research by Michigan State University (see Image 2 above) indicates that: Echinacea are intermediate day plants that flower best under intermediate photoperiods (day lengths). Plants that are exposed to 12 hours of light or less or 16 hours or longer will flower poorly. Echinacea also requires a minimum of 13 to 14 hours of light each day for them actively grow. Shorter photoperiods will cause them to cease active growth and appear small and stunted. Plants grown under continuous light will remain actively growing and will NOT produce flowers. Eliminate Flowering Based on the research results from Michigan State University, growers must produce Echinacea with daylengths greater than 13 hours or the plants will not begin to grow or continue active growth. Many growers observe this when forcing Echinacea in the early spring- there is often an initial flush of growth followed by a period where the plants appear stunted or as if they have been sprayed with PGRs. These plants essentially cease to continue active growth after they are exposed to short photoperiods (less than 13 hours). Following the dormant period, the growth begins as a response to temperature, after several leaves have unfolded they stop growing as a result of short daylengths. Then as the days become naturally longer (by late April), they begin to resume active growth. Unfortunately, they also become reproductive at daylengths of 13 to 14 hours. (In most of the U.S., the natural day length is 13 hours by early April.) Since they easily turn reproductive at nearly the same photoperiods they require for active growth, it is difficult to bulk them up or to produce additional basal branches following the dormant period. Therefore, it is important to bulk them up and obtain adequate basal branches that are well developed before the dormant period. To improve the performance and appearance of containers planted from vernalized liners in the spring, propagators need to take steps to improve the branching and size of basal branches present before overwintering liners. With Echinacea becoming reproductive so easily during the growing season (early April through early September) under the natural photoperiods, it is difficult for growers to bulk them up properly- even when additional production time is provided. However, there is one strategy growers can implement that would keep the plants growing actively AND keep them from becoming reproductive. The research from Michigan State University mentioned above also demonstrated that Echinacea does not flower and remains actively growing when they are grown under continuous light (24 hours). This can be done commercially by providing lights to plants beginning about one hour before dusk until one hour after dawn. This type of lighting should be delivered to any Echinacea, particularly the premium cultivars from tissue culture, which are being propagated and intended to be sold as a vernalized liner, containers that are scheduled to be overwintered, and to spring planted containers intended for same year sales. Continue lighting until the plants reach the desired size- meaning they have an adequate quantity of basal branches and these branches reach a certain size or maturity. This will improve the basal branches ability to survive through the dormant period allowing them to become viable shoots in the spring. Lighting to promote bulking and basal branching also improves plant appearance and quality attributes of plants that are not being overwintered and sold the same year they are transplanted. Basal Branching To increase the number of basal branches, make applications with the plant growth regulator Configure (6-BA) [www.fineamericas.com] as early in the production cycle as possible- the earlier the better. Early applications will allow enough time for the basal shoots to develop and mature- increasing their ability to survive the winter and resume active growth the following spring. Configure applications are most effective when multiple applications are made using 150 to 300 ppm; making applications every 10 to 14 days until the desired quantity of basal branches (3 to 6) are observed. Each cultivar responds to Configure applications differently and will likely require a different number of applications (1 to 3 applications should be sufficient in most circumstances). Configure Trial Results on Echinacea Cultivars - Basal Branches Formed After Midnight Configure 150 ppm (2 appl.): 4.1 Configure 300 ppm (1 appl.): 3.3 Untreated Control: 0.5 Fatal Attraction Configure 150 ppm (2 appl.): 6.2 Configure 300 ppm (1 appl.): 6.5 Untreated Control: 0.7 Pink Double Delight Configure 150 ppm (2 appl.): 9.0 Configure 300 ppm (1 appl.): 4.6 Untreated Control: 3.1 (Research conducted by Perennial Solutions Consulting) Configure is significantly less effective when the plants have visible flower buds present prior to the applications. For the best results, make applications to plants that are actively growing and not reproductive. Applying Configure when the natural photoperiods are less than 13 hours will also decrease the efficacy of Configure applications (unless lighting is provided). The best results will likely be obtained when Configure is applied to plants that are grown with continuous light since these plants remain non-reproductive and actively growing. A slight amount of leaf abnormalities (crinkling and distortion) may occur on the newest foliage following Configure applications. This reaction to Configure is short term and does not negatively affect plant quality later on. Example Echinacea Program for Propagators Begin 24 hour lighting immediately upon placing recently planted stage 3 materials into the propagation environment. If possible, work with the tissue culture laboratories and encourage them to provide 24 hour lighting as well if they are not already doing so. If necessary, transplant to rooted Echinacea liners to larger plug liners and continue 24 hour lighting. Apply 100 ppm Configure around day 14 (after transplanting) once the majority of the plants cells have developed roots to the outside of the liner. It may be necessary to apply Configure to different varieties at different times or to wait until the majority of the varieties are rooted to apply Configure. Apply a second Configure application 14 days after the first application using 150 ppm and make additional applications every 14 days to all varieties that do not have 3 to 6 basal branches on them. Continue with 24 hour lighting until the plants have reached the desired size and the basal branches are well formed, viable, and nearly as large (thickness) as the terminal shoots. Example Echinacea Program for Container Growers Receive vernalized liners week 14 to week 15. Fresh liners (unvernalized) will often have fewer basal branches which will take slightly more time to bulk up. (Do not plant dormant liners – wait for active growth before transplanting, otherwise significant losses may occur). A preventative fungicide drench (Subdue Maxx + Medallion or Subdue Maxx + Cleary's 3336) at transplanting may be beneficial particularly if the root health of the liners is questionable. Begin 24 hour lighting immediately upon receiving and transplanting the liners. Apply 150 to 300 ppm Configure around 14 days after transplanting- once the majority of the containers are actively growing and have roots to the edge of the pot. It may be necessary to apply Configure to different varieties at different times. Make a second Configure 150 to 300 ppm application 14 days after the first application (28 days after being transplanted) to all varieties that do not have at least 3 to 6 basal branches on them. Make a third Configure application 14 days later (42 days after transplanting) to all varieties that do not have at least 3 to 6 basal branches on them. It is not necessary to continue applying Configure to plants that have an adequate number of basal branches. Continue 24 hour lighting until the plants have reached the desired size (fullness – adequate number of actively growing basal shoots) and the basal branches that are present are well formed, viable, and nearly as large (thickness and height) as the terminal shoots. Plants started this year should be intended to be available for sales the following year. Depending on the quality and branching characteristics of some of the cultivars, it may be possible to sell some plants during the same growing season, but for the best quality the majority of them will not be marketable until the following growing season. Fall Fungicide Drench Apply a broad spectrum fungicide drench effective at controlling Fusarium, Phytopthora, and Rhizoctonia approximately one month before the plants are allowed to go dormant. This will allow adequate time to re-grow any roots that have been infected with these pathogens during the growing season and allow the plant to become as strong as possible before the over-wintering period. If the roots are unhealthy going into the winter, they will be weaker and may not be able to survive the dormant period. Fertility During the late summer and fall (late August to late September) only apply enough nutrients to sustain normal growth and development. The fertility levels can be reduced by about half the rates usually applied during the growing season. As the plants go dormant, reduce the rates further or altogether. During the winter months the EC should be at or below 0.7 using the 2:1 media extraction method or 1.5 using the Pour Through Method. Moisture Levels The Echinacea should be kept at moderate moisture levels, but not wet to the touch during the winter months. Keeping them overly wet often leads to the development of crown rots and keeping them overly dry reduces their ability to withstand cold temperatures and may adversely affect their survival. These methods (continuous lighting and Configure applications) when performed properly and early in the production cycle will greatly increase plant quality and appearance, provide a better, stronger plant for overwintering (well branched and non-flowering), and should greatly improve plant survival and quality once plants break dormancy in the spring. Please contact me (firstname.lastname@example.org) to discuss how to implement these strategies into production or if you have any questions about growing Echinacea. The chemicals recommended above have been proven effective and non-phytotoxic under experimental and/or under specific environmental conditions. However, all chemicals and fertilizers should be applied, as directed, on a small scale under existing conditions prior to broad scale use in order to prevent possible plant damage. All pesticides must be applied strictly according to EPA regulations, and label direction on the pesticide containers.