Cat grass is a popular addition for pet owners seeking to provide a safe, appealing green snack for their cats. Offering these cereal grasses to indoor pets helps satisfy a natural grazing instinct and provides dietary fiber. Since it is grown both inside and outside, gardeners often worry if this rapidly growing plant will spread aggressively and become difficult to manage. Understanding the species used and their growth mechanics clarifies that cat grass is not an invasive threat like common lawn weeds.
Understanding the Plants Labeled as Cat Grass
The term “cat grass” is a marketing label applied to the young shoots of various cereal grains, not a single botanical species. Common varieties sold in kits include Wheatgrass (Triticum aestivum), Oat grass (Avena sativa), and Barley grass (Hordeum vulgare). All common cat grass varieties are classified as annuals, meaning their entire life cycle occurs within a single growing season. They are grown primarily for their young blades and are typically consumed or harvested long before they can reach maturity and produce seeds.
Growth Habits and Propagation
The physical structure of these cereal grasses explains why they do not spread aggressively like many perennial lawn weeds. Wheat, oat, and barley grasses are “bunchgrasses” that grow by a process called tillering. Tillering involves the development of new shoots from buds located at the base of the plant, resulting in a dense, tight clump rather than a creeping mat.
Unlike invasive grasses, common cat grass species do not produce horizontal underground stems (rhizomes) or above-ground runners (stolons) that allow lateral spreading. Because cat grass lacks these mechanisms, the only way it can propagate is through seed dispersal. If the plant matures and drops its seeds, new “volunteer” plants can sprout the following season. This reseeding is the primary method of propagation, but it is easily managed.
Controlling Growth Indoors and Outdoors
Managing cat grass growth is straightforward due to its clumping, annual nature. For indoor growing, the grass remains entirely within the pot or tray where it was sown. The entire pot is typically discarded once the grass starts to yellow, signaling the completion of its short life cycle.
Outdoors, controlling the spread is primarily about preventing the plant from reaching maturity and reseeding. If planted in a garden bed, simply remove the entire clump before the blades yellow and seed heads form. Unlike a perennial grass with deep, spreading rhizomes, removing the entire annual plant eliminates the potential for next season’s growth.