Planting low-growing ground covers between flagstones transforms a hardscape pathway into a cohesive, living part of the landscape. This technique softens the harsh, geometric lines of stone, integrating the path into the surrounding garden environment. Beyond aesthetics, filling these spaces with resilient plants helps suppress unwanted weed growth by occupying the available soil surface. The foliage and, in some cases, flowers add welcome texture and fragrance, enhancing the sensory experience of walking along the pathway.
Key Considerations for Plant Selection
Successful planting between flagstones requires selecting species specifically adapted to the unique, challenging environment of a paved walkway. The primary factor is foot traffic tolerance, which determines whether a path can sustain daily walking or only occasional use. Plants must be able to withstand being compressed without significant damage, a resilience that often correlates with a low, mat-forming growth habit.
The spaces between flagstones offer shallow, confined soil pockets that heat up quickly and retain limited moisture. Flagstones absorb and reflect solar radiation, accelerating water evaporation and requiring plants to possess strong drought-tolerance once established. The limited root space necessitates the selection of shallow-rooted species capable of thriving in poor, quickly-draining soil with minimal nutrients. Final selection depends heavily on the specific sun or shade exposure of the path, as this will limit the viable options for a given location.
Recommended Plants for High and Low Traffic Areas
For pathways that receive frequent foot traffic, selecting durable, low-profile groundcovers is important. Creeping Thyme (Thymus serpyllum) is a favored choice, forming dense mats highly tolerant of being stepped on, releasing a pleasant, herbal scent when crushed. Low-growing Sedums, such as Goldmoss Stonecrop (Sedum acre), are succulent species that handle sun, heat, and poor soil well, offering colorful foliage but tolerating moderate traffic only. Green Carpet (Herniaria glabra), also known as Rupturewort, is another resilient option, forming a dense, bright green mat capable of withstanding considerable pressure.
Pathways with low or occasional traffic, such as a patio border, allow for a greater variety of plants with more visual interest. Blue Star Creeper (Isotoma fluviatilis) is a fast-spreading perennial that forms a dense, bright green mat dotted with small, light blue, star-shaped flowers throughout the summer. While it handles light foot traffic, it prefers consistently moist conditions and partial sun, making it less suitable for hot, dry areas. Irish Moss (Sagina subulata) and Scotch Moss (Sagina subulata ‘Aurea’) are not true mosses but form a velvety, cushion-like carpet of bright green or gold foliage in partial shade and moderate moisture.
For areas with deep shade, choices narrow to plants that do not require constant sun exposure. Baby Tears (Soleirolia soleirolii) is an excellent shade-lover that forms a delicate green mat, thriving in moist soil conditions. Creeping Jenny (Lysimachia nummularia ‘Aurea’) has bright, chartreuse foliage and is a vigorous spreader that tolerates both sun and partial shade. However, its tendency to trail requires more frequent trimming to keep it confined to the gaps, and these varieties prefer minimal foot traffic.
Preparing the Space and Planting Techniques
The physical act of preparing the spaces between flagstones ensures the newly planted groundcovers establish quickly and thrive. First, all existing weeds and debris must be thoroughly cleared from the gaps, ideally leaving a space at least one inch wide and four to six inches deep to accommodate root growth. This cleared space should then be filled with an appropriate planting medium, as the native soil is often compacted and nutrient-poor.
A well-draining mix is achieved by combining existing soil with materials like coarse sand, fine gravel, or compost to increase porosity. When planting, the groundcovers are typically purchased as small plugs or mats, which should be divided into smaller sections using a knife or scissors. Each small plant division is then placed firmly into the prepared soil, ensuring the crown of the plant is level with the surface of the flagstone to prevent water pooling or being covered by the stone. A thorough, deep watering immediately after planting settles the soil around the roots and is a crucial final step for establishment.
Ongoing Maintenance for Healthy Pathways
Maintaining a lush, healthy pathway requires focused and consistent care to manage both the plants and the surrounding hardscape. Once the plants are established, the watering schedule should transition from frequent, shallow applications to less frequent but deep soaking. Deep watering encourages the roots to grow down into the soil pocket, increasing the plant’s resilience to drought and heat reflected by the stone.
The vigorous, creeping nature of these plants necessitates regular trimming to prevent them from overtaking the flagstones. Allowing the foliage to grow over the stone edges can create a tripping hazard and trap moisture, which may promote moss or algae growth on the stone itself. Any shoots that spread beyond the desired margin should be snipped back with shears to maintain clean, defined edges.
Weed management remains an ongoing task, as wind-blown seeds will attempt to germinate in the joints. The dense cover of the desired groundcovers helps suppress new weed growth, but any invaders should be manually pulled as soon as they appear. These groundcovers are adapted to lean conditions, so fertilization is rarely necessary; too many nutrients can encourage leggy growth that is less durable.