Clematis, often called the “queen of climbers,” is a popular flowering vine known for its ability to cover walls, trellises, and arbors with vibrant blooms. The speed at which these plants grow is highly variable, depending on whether the vine is newly planted or fully established, the specific variety, and the surrounding environment. Growth rates can range from a slow crawl of a few inches annually for delicate varieties to a rapid extension of over 20 feet in a single season for the most vigorous types.
Growth Rates: Establishment vs. Mature Vines
A common saying among gardeners describes the establishment period of a newly planted Clematis: “The first year they sleep, the second year they creep, and the third year they leap.” This phrase captures the vine’s initial focus on underground development rather than visible top growth.
During the first year (“sleep” phase), the plant dedicates energy to establishing a deep, robust root system. Visible growth above ground is minimal, often only a few inches or a foot. The second year (“creep” phase) sees moderate expansion as the root system develops further and supports more foliage. The vine may add one to three feet of growth and begin to form a recognizable structure.
The “leap” phase begins in the third year, once the root system is fully established and mature. At this point, the Clematis dedicates maximum resources to vertical growth, and the annual extension rate becomes much more dramatic. Mature, vigorous varieties can shoot up 10 to 20 feet or more in a single growing season under ideal conditions, quickly providing the desired coverage.
How Growth Varies by Clematis Group
The inherent growth rate of a Clematis is strongly tied to its genetic makeup, categorized by its pruning group (Group 1, 2, or 3). These groups reflect the plant’s overall vigor and ultimate size.
Group 1 Clematis, such as Clematis montana and C. armandii, are typically the fastest and most aggressive growers. These early-flowering species can reach heights of 20 to 30 feet and quickly cover large areas. Their rapid growth is often noted in the spring before slowing down after the main bloom period.
Group 3 Clematis, including popular varieties like Clematis viticella and ‘Jackmanii,’ are also vigorous growers. Although they are pruned heavily each year (cut back to 6 to 12 inches above the ground), they regrow rapidly from the base to reach their full height of 8 to 12 feet by late summer. The mature root system ensures a quick recovery and substantial new vine extension despite the annual hard pruning.
Group 2 Clematis, which encompasses many large-flowered hybrids like ‘Nelly Moser,’ are generally the least vigorous and slowest to establish. These varieties bloom on both old and new wood, typically reaching heights of 8 to 12 feet. They require more time to achieve their mature size and are often more sensitive to environmental stress, which can further slow their growth rate.
Environmental Factors Influencing Speed
While genetics set the potential for growth, external factors determine whether a Clematis reaches its maximum speed. Providing specific environmental conditions is the most direct way a gardener can optimize growth.
Clematis requires ample sunlight to fuel rapid growth, ideally six or more hours of direct sun per day for the foliage. However, the roots prefer a cool, moist environment, leading to the common advice of planting the “feet in the shade and head in the sun.” This can be achieved by planting low-growing shrubs or applying a thick layer of mulch around the base.
The soil must be fertile, rich in organic matter, and consistently moist, as the plant needs regular water. Poor drainage significantly inhibits growth, as the roots are susceptible to rot. Clematis are considered hungry plants and benefit from regular feeding, often requiring a balanced fertilizer applied during the active growing season.