By Joyce Latimer
Concise (uniconazole, Fine Americas, Inc.) is a plant growth regulator (PGR) used in greenhouse and nursery structures (lath or shade houses) to regulate shoot growth of bedding plants, garden mums, poinsettias, herbaceous perennials, bulb crops, woody ornamentals, and other containerized crops. Concise typically reduces the elongation of stem, petiole and flower stalk tissues. Lesser effects are seen as reductions of leaf expansion, resulting in thicker leaves with darker green color. Other benefits of using Concise in plant production include improved plant appearance by maintaining plant size and shape in proportion with the pot. Concise also increases the stress tolerance of plants, which improves their tolerance to shipping and handling and retail marketing, e.g., improving shelf-life and extending plant marketability. Concise can improve plant quality and appearance without a noticeable reduction in plant height.
Concise is a great product for use on herbaceous perennials to optimize growth control. It is a very potent PGR that is generally used at low rates (5 to 30 ppm sprays). We like it for use on perennials because we have a fairly wide range of rates that give a linear amount of growth control. In other words, we can see a consistent increase in growth regulation with higher rates before the response is saturated. With the variability in responsiveness to PGRs, this makes uniconazole our product of choice for containerized perennials.
Tips on optimizing growth regulation with Concise:
- Species respond differently to Concise applications. In addition, cultivars of the same species may respond differently to Concise rates. More vigorous cultivars generally require higher rates of Concise for optimal height control than dwarf or slower growing cultivars.
- Concise can be used in conjunction with a number of non-chemical control options to manipulate plant growth and quality:
- Plants grown in small pots at close spacing will require more Concise for adequate growth control than those receiving ample light.
- Spacing will often determine the need for, and amount of, additional chemical control necessary for optimum height control under high light levels.
- Growers who tend to “run their plants dry” will use less Concise than growers who run their plants “wet”.
- As with “dry” plants, nutrient-hungry plants require less Concise for growth control than lush plants.
- Lower rates of PGRs like Concise are required for plants grown under lower temperatures.
- Optimizing plant growth control requires an understanding of the effects of environmental and cultural conditions on plant growth. Experience and onsite trials – along with good records – will allow you to combine PGRs with a number of non-chemical control options to optimize the quality, compact plants.
Tips on Concise applications:
- Look for recommendations on the Concise label for time of application, in terms of plant development or plant size as opposed to production time. Generally, this will be just prior to rapid shoot growth following transplanting, or when new shoots are visible and starting to elongate on pinched or overwintered plants. You must learn how your crop grows and when to intervene to obtain the desired results. The earlier the application, the greater the growth control.
- Be accurate in measuring, mixing and applying Concise. Remember that Concise is very potent. Consistent results will depend on proper preparation and a consistent volume of application. Consider using multiple applications to improve crop uniformity.
- Be aware that Concise is not yet labeled for use in the irrigation system (chemigation).
- Treated plants may be irrigated one hour after treatment.
- Applications, especially foliar sprays, should be made when plants are not under environmental stress.
- Read the label for any additional warnings on how irrigation or environmental conditions will affect plant response to the Concise treatment.
- The label also identifies legal methods of application. In addition to foliar sprays, pre-plant substrate applications, drenches, and bulb soaks, the most recent label update includes the use of Concise for liner soaks (See figure 1).