Hickory trees, members of the genus Carya, are highly valued North American hardwoods known for their durable wood and edible nuts. These deciduous trees are generally categorized as slow-growing, a characteristic that contributes to their impressive strength and longevity. While all hickories share a reputation for deliberate growth, the exact rate at which a tree gains height each year is not fixed. The speed of growth is instead a variable factor, determined by the tree’s specific genetic makeup and the quality of its surrounding environment.
Typical Annual Growth Rate
The average annual height increase for most hickory trees places them firmly in the slow-growing category, defined by arborists as less than 12 inches of vertical growth per year. A typical hickory species, such as a Shagbark, generally gains between 6 and 12 inches annually when planted in adequate conditions. This measured pace of growth is a trade-off for the dense, strong wood that makes hickory lumber so desirable.
Hickory growth is relatively faster during its juvenile phase before settling into a slower, mature rate. Seedlings and young saplings prioritize developing a large, deep taproot for stability and nutrient access, often at the expense of above-ground height. This early investment means that while a young tree may seem slow, it is building the foundation required for decades of life.
A hickory tree exhibiting this typical slow growth rate may take anywhere from 20 to 40 years to reach a height of 20 feet. For comparison, many faster hardwoods reach that height in less than a decade. The time it takes for a hickory to reach a mature height of 60 to 80 feet is typically between 40 and 60 years, with some species continuing to add size for a century or more.
How Species Affects Growth Speed
The most significant variation in annual growth speed within the genus Carya is determined by the species’ inherent genetic programming. The fastest-growing member of the group is the Pecan (Carya illinoinensis), which can be classified as having a moderate to fast growth rate. Young Pecan trees can easily add 1 to 2 feet of vertical growth each year, and in ideal growing conditions, they may even achieve 3 to 4 feet of annual height increase. This faster growth potential makes the Pecan an outlier among its relatives.
In stark contrast, the true hickories, such as the Shagbark (Carya ovata) and the Pignut (Carya glabra), are classic examples of slow-growing hardwoods. Shagbark hickories rarely exceed 1 foot of growth per year, maintaining a consistent pace. The Mockernut (Carya tomentosa) is noted for its moderate to slow speed, and the Shellbark hickory (Carya laciniosa) is regarded as one of the most extremely slow-growing species in the genus.
These species-specific differences mean that the maximum potential speed of a hickory is pre-determined by its type. A Pecan planted under less-than-perfect conditions may still outpace a Pignut hickory planted in optimal soil, simply because of its genetic capacity for faster height gain.
Environmental Conditions That Influence Growth
Beyond the genetic blueprint of the species, the local environment acts as a powerful accelerator or decelerator for a hickory tree’s annual growth rate. Sunlight is one of the most influential external factors, as all hickories require full sun exposure, meaning at least six hours of direct, unfiltered sunlight daily, for optimal growth. Trees planted in partial shade will survive, but their growth will be noticeably stunted, often remaining at the lowest end of the species’ potential range.
Soil quality and composition also directly impact the speed of a hickory’s development. These trees thrive best in deep, well-drained, and highly fertile loamy soils, which allow their extensive taproot systems to penetrate easily and absorb nutrients. A slightly acidic pH range of 6.0 to 7.0 is preferred for efficient nutrient uptake. Growth slows considerably in dense, compacted clay or in highly alkaline soils where essential micronutrients become unavailable.
Water availability can either boost or severely restrict annual height gain, especially in young trees. While established hickories exhibit good drought tolerance due to their deep taproots, a lack of consistent moisture during the growing season will severely reduce new growth. Providing deep, infrequent watering during dry periods encourages the root system to grow downward, promoting stability and faster establishment. Managing competition from weeds and grass around the base of the tree ensures unimpeded access to necessary moisture and soil nutrients.