Tolerance versus Resistance – Understanding Drought and Its Significance to Landscape Material

Climate, the typical weather patterns of a region over an extended period of time, is generally divided into five distinct patterns in accordance with the Köppen classification system. The classifications include (1) tropical, (2) arid, (3) warm, (4) continental, and (5) polar. Each zone is then divided further based on variables including temperature and dryness. Florida falls across several divides of the Köppen classification system dependent upon whether one is discussing South Florida, Central Florida, or North Florida. However, for the most part, Florida is considered to be a humid subtropical climate. It is the climate of any given region that has a significant impact on the hardiness of plant materials including turf.

Often, in landscaping, the terms drought tolerant and drought resistant are used interchangeably at the expense of the plant material being considered. Drought tolerance implies that a particular plant, shrub, or type of turf has acclimated itself to be able to survive prolonged periods in which access to water resources are limited. Yet, survival does not necessarily mean that the plant will recover or even thrive. Tolerance allows for the acclimation to the lack of water (abiotic stressor), but it weakens the plant material or turf to the biotic stressors – disease and pests. The longer the exposure to the abiotic stressor without significant intervention the less likely the material will recover.

Drought resistance is an indication that the plant material has successfully immunized, or modified its biological responses, in order to adapt to dry conditions without being further impacted by biotic stressors. Plant materials, much like humans, attempt to defend themselves to stressors through a variety of mechanisms including avoidance, escape, tolerance, and recovery. Drought stress happens when water loss from the plant exceeds the ability of the roots to absorb water to support normal processes. Typically, drought stress is evident in turf when the blades fail to spring back from foot traffic, heavy mow lines are apparent, and the turf begins to brown and crunch when walked on. In trees the stress will appear as a dropping of foliage from the upper center of the canopy while flowers may stop growing, wilt, turn brown, and eventually die.

Understanding that Florida has an annual rainfall of 54 inches per year often coinciding with extended periods of drought is the first method for combating potential drought stress in the landscape. Armed with this knowledge, steps can be taken to select the right plant for the right place, and adjusting irrigation layouts or schedules to provide sufficient water access during drought conditions. At LMP, we have teams of highly qualified individuals whom can evaluate the irrigation system at your property, and assist in selecting the right plant for the right place. Call us at (877) LMP-PRO1 to learn how LMP can help with all your landscape needs.

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