Mexican petunia (Ruellia simplex) is a popular and durable garden perennial, valued in warmer regions for its long blooming season and ability to thrive in varied conditions. A common concern in areas with high wildlife activity is whether this attractive plant will become a meal for browsing deer. Understanding the plant’s characteristics and the feeding habits of local deer populations provides the answer to this frequent gardening question, helping home gardeners make informed decisions.
Identification and Characteristics of Mexican Petunias
Mexican petunia (Ruellia simplex) is an ornamental herbaceous perennial that forms an upright, shrubby clump. It is characterized by linear, lance-shaped, dark green leaves that can grow up to 12 inches long. Its showy, trumpet-shaped flowers resemble true petunias, appearing in shades of purple, pink, or white, and are beloved by pollinators like butterflies.
The plant is highly adaptable, tolerating a wide range of moisture levels, from boggy soils to drought conditions once established. While it is a vigorous grower, its tendency to spread aggressively via rhizomes and self-seeding has led to it being considered invasive in some warm regions, such as Florida. Breeders have developed less aggressive cultivars, including dwarf varieties like ‘Katie’ and sterile forms like ‘Purple Showers,’ which offer a more controlled growth habit.
The Primary Question: Deer Resistance
Mexican petunias are classified as highly deer-resistant, making them a reliable choice for landscapes prone to browsing pressure. Deer tend to avoid this plant and seldom damage it, even when other garden plants are heavily browsed. This resistance is attributed to the plant’s physical and chemical makeup, which makes the foliage unappealing.
The leaves possess a slightly bitter taste, acting as a major deterrent to grazing animals. Deer are selective feeders, preferring soft, succulent, and highly digestible plants. They typically pass over plants with unpalatable flavors or tougher textures, selecting more palatable food sources first.
Situational Exceptions and Prevention
While Mexican petunias are resistant, no plant is completely deer-proof, and browsing can occasionally occur under specific environmental conditions. Deer may resort to eating less desirable plants during periods of extreme food scarcity, such as severe drought or late winter when preferred forage is unavailable. Young, newly planted Mexican petunias, which have softer, more tender growth, are also slightly more vulnerable than mature, established clumps.
If deer browsing is a persistent issue, gardeners can employ several preventative measures. One effective non-chemical method is installing temporary physical barriers, such as netting or fine-mesh fencing, around new plants until they mature. For broader protection, gardeners can apply topical deer repellents that use scent or taste to discourage feeding. These commercial repellents often contain ingredients like putrid egg solids or capsaicin, which must be reapplied after heavy rain or at regular intervals to maintain effectiveness.