Hoary verbena, or Verbena stricta, is known for its tall plumes of purple flowers. It will easily overtake an overgrazed pasture, but it is not known to be aggressive or invasive. It germinates easily from seed.
I. Appearance and Characteristics
Verbena stricta, also known as hoary verbena or hoary vervain, is a small purple wildflower native to a large region of the central United States.
Verbena stricta is native to Oklahoma, Kansas, Nebraska, South Dakota, North Dakota, Colorado, Wyoming, Minnesota, Wisconsin, Michigan, Iowa, Indiana, Illinois, and Ohio. Because of its versatility and hardiness, the species is even more widespread; the only states where it does not appear are Oregon, California, Louisiana, Florida, South Carolina, Virginia, New Jersey, Connecticut, Rhode Island, Massachusetts, Vermont, New Hampshire, and Maine.
It is mostly found in meadows; fields; dry, sandy soils; and anthropogenic biomes, which include man-made or disturbed habitats. Due to the habitats V. stricta lives in, it is an extremely drought-resistant and nonaggressive species.
Growth
In ideal growing conditions it can grow up to 2–4 feet (0.6–1.2 m) with a spike topping the plant. This spike includes a densely packed cluster of half-inch (1 cm) flowers.
Flower
The flowers can bloom in a variety of colors, the majority of them purple or a lavender shade, with rose pink or white rarely appearing. The flower includes five petals fused at the base, forming a short tube. The petal lobes are unequal in size and length, with the two later lobes being the largest and a notched lobe at the top of the bottom lobe. As the plant ages, the spike atop the plant will elongate. The spike topping the plant will eventually seed and encapsulate tiny nutlets. The fruit is usually 0.08–0.12 inches (2–3 mm) in length when ripe.
Leaves
The leaves are, on average, 2–3 inches (5–8 cm) long with an opposite pattern along the stem of the plant. The leaves have a heavy serrated edge with an oval to egg shape and a pointed tip. All leaves are covered in dense hair and are completely stalkless. The stems of this plant are square and are also covered in short, dense hair. The base of the stem can include a reddish color.
Season
Verbena stricta blooms in the early summer and stays flowering through September until its seeds ripen.
II. How to Grow and Care
Hoary verbena thrives best in full sun exposure and well-drained soils, demonstrating a preference for drier conditions. Watering should be moderate to low, as hoary verbena is tolerant of drought and overwatering can lead to root rot. No specific requirement for fertilization makes hoary verbena a low-maintenance choice for gardeners seeking resilient flowering plants.
Sunlight
For the small clusters of flowers to maintain their bright colors in pink, yellow, and purple, the hoary verbena must have plenty of sunlight. While you can grow it in a slightly shaded area, it is recommended that the hoary verbena has a minimum of six hours of sunlight each day. Any less than this and your flowers may be dull in color.
Temperature
Native to Northern America, Asia and Europe, the hoary verbena is a hardy plant. While it can survive in temperatures between 14 to 19 ℃, it prefers temperatures between 20 to 26 ℃ to encourage an abundance of flowers. While it is technically a perennial, some find it easier to grow the hoary verbena as an annual plant, depending on location and variety.
Watering
Thriving in its native prairie habitat, hoary verbena is well-adapted to periodic dry spells, exhibiting a preference for moderate moisture levels. This species maintains a balance between drought resistance and the need for consistent hydration. For optimal growth, watering every week is recommended. As an herbaceous perennial commonly grown outdoors, hoary verbena has adapted to seasonal rainfall patterns, which influence its growth cycles and water requirements.
Soil
While the hoary verbena is not too fussy about what type of soil it is planted in, it does need to be in a well-draining one. For example, loamy soil with a PH value of 6-7 (so slightly acidic) would be absolutely ideal. If possible, choose a soil that is fertile and rich in nutrients, but not one that is heavy, such as clay.
Fertilizing
For hoary verbena, use a balanced fertilizer to encourage robust growth and vibrant blooms. Apply it once a month during the growing season at the manufacturer’s recommended dose. Over-fertilization can lead to excessive foliage with fewer flowers, so adhere to guidelines. Inactive periods require less frequent feeding. Granular or liquid options are suitable; however, liquids are preferred for more immediate uptake. Always water hoary verbena after fertilizing to help nutrient absorption and prevent root burn.
Pruning
Depending on the variety of hoary verbena, it can grow between 10 to 140 cm in height and 2 m wide in its spread.
The hoary verbena will bloom from the beginning of summer until the middle of winter, when the first frost arrives. Because of the plant’s large amount of bloomage, it can quickly start to look a little disheveled if not pruned regularly. To avoid this, prune every month in the summer. Throughout the rest of the year, consider pruning your hoary verbena twice each season if it requires it.
During summer, when the plant is in bloom, trim back any spent flowers or withered foliage. If regularly pruning, trimming back by 2.5 to 5 cm each time will help to maintain your plant’s shape. Also, pinch tips to encourage more abundant blooms in other areas of the plant. Avoid removing over a third of the plant overall, as this may affect flowering in the future.
Propagation
Hoary verbena thrives when propagated through cutting methods, which fosters robust root development and ensures genetic consistency in new plants. Gardeners should select healthy, non-flowering stems for cuttings to increase success rates. Once cut, stems should be placed in a rooting medium that is kept moist but not waterlogged, promoting optimal root growth. This allows for effective acclimation when transplanting to a permanent outdoor environment.
Transplanting
The twilight of summer into autumn’s embrace is an ideal time to transplant hoary verbena, ensuring milder weather for root establishment. Select a sun-kissed spot with well-drained soil to optimize growth and vigor.
III. Uses and Benefits
Verbena stricta is an extremely important component of many butterfly gardens, as the leaves are the ideal food for the larval form of the common buckeye butterfly. The seeds are also an important dietary portion of many small birds and mammals.