Weed barriers vary as much as the preferences of the gardeners who use them. Some gardeners rely on synthetic solutions such as impermeable black plastic or porous landscape fabric. Others stick with organic weed barriers such as compost or wood mulches. For plants that reproduce through stolons, the type of weed barrier and its condition determine the plant's ability to grow and spread. Whether you want to inhibit growth or encourage it, your weed barrier holds the key.
When new plants emerge, they send up shoots to form stems and leaves. For stoloniferous plants, a second type of shoot eventually appears. Called stolons, these modified shoots differ from regular shoots. Generally long and thin, they grow from the plant crown above ground. Properly installed weed barriers inhibit plant growth from below, but don't affect growth above. Stolons develop joints or nodes along their length. They may arch up and out toward the ground or grow horizontally along the surface. At the nodes or tips, regular shoots and roots create new plants. Stolons function as pathways for nutrients between mother plants and tiny offspring.
Recognizing Types of Stolons
Many familiar plants produce stolons. One well-known example is the spider plant (Chlorophytum comosum), hardy in U.S. Department of Agriculture plant hardiness zones 9 through 11. Whether planted in warm-climate gardens or in containers, spider stolons arch toward the ground and form new plantlets at their tips. Each tiny plant has leafy shoots and roots that readily sink into soil when given the chance. Strawberries (Fragaria spp.), hardy from USDA zones 3 through 9, form stolons known as runners, which race along the ground. As runner nodes touch soil, where weed barriers allow, roots and new strawberry plants burst forth.
Fulfilling the Stolon Mission
Stolons exist solely for reproduction. They seek out new territory, seize rooting opportunities and bear new plants identical to their source. To survive without a stolon lifeline, plantlets must have a place where they can put down roots. Organic weed barriers such as compost provide a perfect medium for stolons to root and spread. Inorganic barriers, depending on their makeup, may keep roots from becoming self-supporting. Either way, stolons continue to grow on top of weed barriers and produce new, stolon-dependent plantlets, looking for places to take hold. When that happens -- or someone transplants the small plant -- reproduction is complete, and the specialized stolon shoot shuts down.
Interacting With Weed Barriers
Even with impermeable weed barriers in place, stolon plants can spread. Barriers are often beautified with mulch or compost coverings. Paired with accumulating dust, this allows stolon-borne plantlets to mature and produce stolons of their own. As exposure and decomposition break down weed barriers, stolon plants hasten the process. Many turf and weed grasses produce stolons that flourish on top of weed barriers whenever conditions allows. Bermuda grass (Cynodon dactylon), hardy in USDA zones 7 through 10, spreads by vigorous stolons above ground. It also spreads by underground shoots known as rhizomes, which tackle aging weed barriers from below.
- UCLA Life Sciences Division Mildred E. Mathias Botanical Garden: Stolon
- University of Arizona College of Agriculture Cooperative Extension: Botany: Plant Parts and Functions
- Washington State University Puyallup Research and Extension Center: The Myth of Landscape Fabric
- Missouri Botanical Garden: Chlorophytum Comosum
- Missouri Botanical Garden: Fragaria
- Seedland: Climate Maps, Grass Type Chart and More
- John A. Roncoroni, Weed Science Farm Adviser; University of California Cooperative Extension; Napa, California
- Photo Credit laurent rozier/iStock/Getty Images