Zoysia grass is a warm-season turf valued for its dense, carpet-like appearance. This spreading occurs through the growth of two specialized stems: stolons (above-ground runners) and rhizomes (underground runners). While Zoysia is often slow to establish compared to other grass types, specific management practices can significantly accelerate this lateral growth process. By optimizing the soil environment, nutrient delivery, mowing habits, and water application, homeowners can encourage the plant to devote more energy to producing these runners for rapid, dense coverage.
Preparing the Ground for Rapid Expansion
Zoysia’s dense growth habit makes it susceptible to developing a thick layer of thatch, which is a build-up of organic matter between the green blades and the soil surface. This thatch layer can impede the ability of new stolons to make contact with the soil and root, slowing the overall spread. Dethatching is only necessary every three to five years, but it should be done during the active growing season in late spring or early summer to ensure quick recovery.
Soil compaction is another physical barrier to expansion, restricting the movement of both roots and underground rhizomes. Core aeration relieves this compaction by pulling small plugs of soil, allowing air, water, and nutrients to penetrate deeper into the root zone. The timing for aeration, like dethatching, is best during the late spring or summer when the grass is actively growing and can quickly recover. Furthermore, core aeration can physically cut surface stolons, which often encourages them to branch and multiply, leading to faster thickening of the lawn.
Strategic Fertilization for Lateral Growth
Nitrogen is the primary nutrient that fuels the vegetative growth responsible for Zoysia’s lateral spread. Applying nitrogen too early in the spring can promote premature top growth and benefit weeds before the Zoysia is actively growing. The optimal time to begin fertilization is when the grass is fully out of dormancy and soil temperatures are consistently warm, typically beginning in late spring, around May.
During the peak growing season from May through August, Zoysia needs a steady supply of nitrogen to maximize runner development. It is best to use a slow-release nitrogen source, which provides a consistent feed over an extended period and minimizes the risk of burning the grass. Apply no more than one pound of actual nitrogen per 1,000 square feet in a single application. Using a fertilizer with a high nitrogen ratio, such as a 3:1:1 or 4:1:1 N-P-K blend, provides the necessary energy to drive the production of new stolons and rhizomes.
Mowing Techniques to Promote Spreading
The height at which Zoysia is mowed directly influences how it allocates its energy between vertical leaf growth and horizontal spreading. Zoysia performs well when maintained at a relatively short height, often between one and two inches for residential lawns. Maintaining a shorter, consistent height encourages the grass to produce dense, lateral growth rather than simply growing taller.
Mowing frequency is just as important as the height, especially during the active summer growing season. Zoysia should be mowed frequently enough that no more than one-third of the total blade height is removed in a single session. This practice prevents stress and scalping, which would otherwise divert energy away from runner production and into recovery. Using a mower with a sharp blade is also necessary, as dull blades tear the tough Zoysia leaves, leaving frayed edges that increase stress and disease risk.
Optimized Watering Schedules for Runner Development
While Zoysia is drought-tolerant once established, aggressive lateral expansion requires consistent moisture to support the energy-intensive growth of new runners. The best watering strategy involves deep and infrequent applications, aiming to deliver about one to one-and-a-half inches of water per week. This amount is typically applied in a single session or split into two sessions per week, depending on heat and soil type.
Deep watering encourages the development of strong, deep root systems, which support the extended network of surface and subsurface runners. Shallow, frequent watering is counterproductive because it encourages surface roots, making the new growth less resilient and more susceptible to heat stress and disease. Watering early in the morning is recommended to minimize water loss from evaporation and allow the grass blades to dry quickly, reducing the potential for fungal diseases like Zoysia patch.