Four O’Clocks (Mirabilis jalapa) are garden favorites, prized for their vibrant, trumpet-shaped flowers that unfurl in the late afternoon and fill the evening air with a sweet fragrance. Originating in tropical South America, these plants are also known as the Marvel of Peru and thrive in many environments. Gardeners who share their space with white-tailed deer often wonder if these attractive plants will be destroyed by browsing.
The Standard Status of Resistance
Four O’Clocks are widely classified as a deer-resistant species across gardening resources. They are consistently placed in categories designated as “rarely damaged” by browsing animals, confirming a high degree of natural defense. This means that while the plant is not entirely immune, it is highly unpalatable to deer under normal circumstances. Deer tend to avoid Mirabilis jalapa when more palatable food sources are readily available.
Browsing typically only occurs in scenarios of extreme resource scarcity, such as during severe drought or high deer population density. Even then, an animal will usually sample the plant, quickly reject the taste, and move on without causing lasting damage. Gardeners can generally rely on Four O’Clocks to remain untouched, making them a dependable choice for planting near borders or in open areas.
Factors Contributing to Deer Avoidance
The deer resistance of Four O’Clocks is directly linked to the plant’s internal chemistry, which includes compounds that make it bitter and potentially toxic. The entire plant, especially the seeds, contains a complex mix of phytochemicals, including alkaloids, tannins, and saponins. Alkaloids are nitrogen-containing compounds characterized by a bitter taste, which serves as an immediate deterrent to herbivores.
These compounds act as the plant’s natural defense mechanism, signaling unsuitability for consumption through taste and mild toxicity. The combination of these substances ensures that even a small exploratory bite is unpleasant enough to condition the animal to avoid the plant. Additionally, the plant’s strong, sweet scent, while attractive to night-pollinating moths, may not be appealing to deer.
Managing Four O’Clocks in High-Pressure Areas
While Four O’Clocks possess strong natural defenses, the plants are not completely deer-proof, especially when young or stressed. Deer in areas with limited forage may sample tender new growth or young seedlings before the deterrent compounds are fully concentrated. Gardeners in high-pressure zones, where deer are frequent visitors, should be aware of this vulnerability during the plant’s establishment phase.
To mitigate risk, temporary caging or fencing can be used to protect small plants until they reach a mature size. Once established, the plant’s robust unpalatability can be strategically leveraged by planting Four O’Clocks around other, more desirable flowers. This creates a natural barrier that may encourage deer to bypass the entire section of the garden.