Plant growth regulators, or PGRs, are chemical tools developed to reduce the growth of turf and ornamentals. Their advantage is obvious: the slower plants grow, the less maintenance required by you. This is especially useful in situations where you are working to maintain large areas where the cost of applying these chemicals is significantly less than what it would cost for frequent maintenance. While this is perhaps their best-known attribute, there are other reasons to use PGRs.
When you use a PGR on turf, it can improve the overall health of the plant and boost stress tolerance. There is even evidence to suggest that it promotes root development and results in better color of turf. PGRs also can eliminate tall seedheads, which improves the look of the landscape and means that you won’t be tempted to mow again just to knock down the seedheads for aesthetic purposes. During overseeding, you also can use PGRs to slow growth of existing turf to give new seedlings a head start. Another popular use of PGRs is as an “edger” around mowing obstacles, such as trees and other permanent landscape fixtures, which will cut down time spent trimming around these objects.
In ornamentals, you may want to use a PGR to stop fruit growth in areas where pedestrians could be in danger of falling fruit.
If you’re looking to add PGRs as a chemical tool in your business, or if you simply want to review the PGR products available to you, we have outlined them by active ingredient in the following tables, separated by those registered for turfgrass and those registered for use on landscape ornamentals. In “Sources of PGRs,” you’ll be able to cross reference each active ingredient to find brand names and suppliers.
Remember, these specification charts are only for reference. They are not a recommendation for use, nor are they a substitution for application instructions. Some of these chemicals are not for residential use, only for commercial use on turf and ornamentals. As always, consult the product label and follow all label instructions.
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Look for these chemical guides in coming months:
May ~ Insecticides
June ~ Fungicides
July ~ Adjuvants/wetting agents
August ~ Non-selective herbicides
December ~ Vertebrate pest controls