The Verbena plant, often known as vervain, is a gardener’s favorite for adding vibrant, non-stop color to container displays throughout the warmer months. While some varieties are true perennials, the Verbena most commonly grown in pots are hybrids like Verbena x hybrida, which are typically treated as long-blooming annuals. This plant is highly valued in container gardening because of its extended flowering season, which can last from late spring until the first heavy frost. Its natural heat and drought tolerance, once established, make it a relatively low-maintenance choice for sunny patios and balconies.
Setting Up the Container Environment
Successfully growing verbena in a pot begins with providing the right physical environment, focusing specifically on drainage and sunlight. The container must have adequate drainage holes, as the plant is highly susceptible to root rot if the roots sit in standing water. Using a high-quality, all-purpose potting mix is necessary, because garden soil tends to be too dense and holds too much moisture for container life.
Verbena demands a location that receives a minimum of six to eight hours of direct sunlight each day for optimal growth and abundant flower production. Placing the pot in full sun helps the plant thrive and also encourages the quick evaporation of excess moisture. A lack of adequate light will result in weak, “leggy” growth and a significant reduction in the number of blooms.
Essential Watering and Feeding Routines
Watering potted verbena requires a balanced approach that respects its inherent drought tolerance while recognizing the limited volume of a container. The most important rule is to allow the top one to two inches of the potting mix to dry out completely between waterings. This cycle of moisture and dryness is better for the plant than maintaining consistently damp soil, which is the primary cause of fungal diseases and root death.
During periods of high heat, especially in smaller containers, you may need to water daily, but you must always ensure the water drains completely from the bottom of the pot. Watering in the morning is generally best, as it allows any splashed foliage to dry quickly, reducing the risk of powdery mildew. Verbena in containers requires more frequent feeding than those planted in the ground because the nutrients leach out quickly with watering.
After the initial nutrients in the potting mix are depleted, usually after about a month, switch to a regular feeding schedule. The best choice is a liquid fertilizer applied every two to four weeks that is lower in nitrogen and higher in phosphorus. Excessive nitrogen encourages leafy growth at the expense of flowers, so focusing on a formula that supports bloom development will ensure continuous color.
Pruning for Maximum Blooms and Plant Health
Regular physical maintenance is necessary to encourage verbena’s long bloom season and prevent the plant from becoming sparse. The process known as “deadheading,” or removing spent flower clusters, redirects the plant’s energy away from seed production and back into creating new flowers. While some newer hybrid varieties are “self-cleaning,” manually trimming back the faded blooms helps maintain a tidy appearance and promotes a more vigorous rebloom.
To prevent the plant from becoming long and spindly, the “mid-season chop” is highly effective. Around mid-summer or when the plant looks noticeably tired, use clean shears to cut the entire plant back by about 25 to 50 percent of its length. This severe trim forces the plant to branch out laterally, creating a fuller, bushier shape and triggering a robust new flush of blooms a few weeks later. Providing good air circulation around the potted plant also helps prevent common issues like powdery mildew.
Preparing Potted Verbena for Winter
The majority of verbena hybrids commonly sold for containers are not cold-hardy and will not survive freezing temperatures outdoors. If you wish to keep a tender perennial variety for the following season, you must prepare for a period of winter dormancy. Before the first hard frost arrives, cut the foliage back by about one-third to reduce the plant’s size and energy needs.
Move the container to a sheltered, unheated location, such as a cool greenhouse, basement, or attached garage, where temperatures remain above freezing. The ideal overwintering spot should be bright but cool, maintaining a temperature between 40 and 50 degrees Fahrenheit. During this dormant phase, drastically reduce watering to only what is necessary to keep the soil from completely drying out.