2019 ASHS Annual Conference

The landscape maintenance industry generates important economic contributions in the United States; over 1 million jobs and $54.7 billion in total sales in 2013 (Hodges et al., 2015). According to Lawn & Landscape (2015) State of the Industry Report, landscape maintenance is the category predicted to grow the fastest in this industry. Among all landscape plants, shrubs are an essential part of the landscapes. Shrubs provide color, forms, textures, shades, coverage, and noise-cancelling features to the place they are set (Rainbow, 2016). Shrubs draw attention at first sight, and this impact can be negative if shrubs are not correctly treated and maintained. In other words, shrub maintenance is a major way for landscape maintenance companies to convey the quality of their services.

Labor is the single largest expense in agriculture, and the landscape maintenance industry is not an exception. Labor costs can represent between 30% to 55% of all costs for landscape business (IBIS World, 2018). Thus, labor savings is one of the most important tasks for business owners and managers in the industry. In looking for cost-effective ways to lower labor costs, landscape maintenance businesses have started using Plant Growth Regulators (PGRs), being Paclobutrazol one of the most tested products. PGRs are regularly applied in commercial ornamental plant production to control growth (Gent and McAvoy, 2000). PGRs suppress shoot growth by blocking the production of phytohormones associated with plant cell elongation (Hedden and Graebe, 1985).

Some of the industry claims on the benefits of PGRs for shrub maintenance are reducing shorter pruning time, delaying spring and early summer pruning, increasing labor safety, improved plant appearance, and freeing labor time for other jobs. Our study investigates the economic benefits of PGRs on the labor savings of landscape maintenance companies. Specifically, we investigate the labor savings (in dollars) determined by shortening pruning time and waste disposal reductions. We also draw conclusions on potential labor reallocation savings and labor safety.

Our data comes from experiments conducted in Buena Vista & Western Bay (Florida), Cinco Ranch (Texas), Raceway area by golf course (Indiana) and Leesburg, Ocala (Florida). We used number of prunes per year and hours of pruning to measure the reduction of growth in 5 shrub species: Confederate jasmine, Asiatic jasmine, Thorny eleagnus, Viburnum odoratissimum and Ligustrum japonicum.

We used a partial budget analysis to evaluate the financial effect of incremental changes in labor savings due to an adoption of PGRs for shrub maintenance. The partial budget analysis uses only the additional inputs and outputs generated due to the use of PGRs in shrubs, rather than an entire company budget. Similar studies have used partial budget analysis to understand the money saving effect of technologies in agriculture (Barret et al., 2012).

We will also perform a sensitivity analysis on two different variables: the variations in growth reduction due to PGR rates and labor wages. The sensitivity analysis can allow us to understand how savings respond to changes on shrub growth reduction and labor wages (Boardman et al., 2001). Finally, we will survey landscape businesses to understand their labor reallocation preferences due to shorter pruning time, delayed pruning time peaks, and occupational safety.

PGR treatments were issued in periods of 6-week and 12-weeks, with application rates of 9.6 fl. oz./gal and 6.4 fl. oz./gal. Shrubs received, on average, 2 applications of PGR per year, with a reapplication interval of 12 weeks after the initial treatment. Pruning of untreated shrubs occurred 8 to 30 times/year, while treated shrubs were pruned 2 to 7 times/year, depending on the specie. PGR application took 2.86 minutes/gallon covering 461 square-feet, on average. Additional variables analyzed were pruning time, waste biomass reduction (averaged between 34% and 36% based on Ligustrum japonicum).

Some results show that applying PGRs can, on average, reduce the number of prunes by 64.5% and the time of pruning by 56%. Together, these results show landscape maintenance businesses can reduce 443 hours of labor per year due to labor savings in pruning, depending on shrub specie. Considering a minimum wage of $7.25/hour, this translates into savings of around $3,217 per year. In addition to the data obtained from the study, our study will draw conclusions on improved occupational safety, labor reallocation savings, and labor productivity due to shorter maintenance time.