Shrubs are woody perennial plants that provide structure, color, and habitat in the landscape. Their long-term success is determined by when they are initially planted. Planting a shrub at the right time allows its root system to establish itself before the plant is subjected to seasonal stresses like extreme heat or freezing temperatures. Understanding the optimal windows for root growth, rather than just the air temperature, is the most important factor in ensuring a healthy start.
The Best Times: Spring and Fall
The two best times for planting shrubs are spring and fall, as these periods offer the ideal balance of soil warmth, moisture, and air temperature. Spring planting should occur after the last hard frost but before the intense heat of mid-summer begins. This timing allows the shrub to establish new feeder roots capable of absorbing the water needed to survive summer stress and potential drought conditions.
Fall planting is often preferred because it provides an extended window for root development without the competing energy demands of top growth. Ideally, a shrub should be planted six to eight weeks before the ground is expected to freeze solid. The soil retains warmth, encouraging root growth, while cooler air temperatures minimize the plant’s need to produce new leaves or flowers. This energy is channeled downward, allowing the root system to become robust and ready for growth the following spring.
Timing Based on Shrub Type
The physical state of the shrub significantly influences the flexibility of its planting schedule.
Bare-Root Stock
Shrubs sold as bare-root stock have had all the soil washed from their roots and must be planted immediately. These plants should only be planted when they are fully dormant, typically in very early spring before buds break, or sometimes in late fall if the ground is soft. Planting bare-root stock outside of dormancy means the exposed roots will dry out quickly, reducing the plant’s survival rate.
Containerized and Balled and Burlapped (B&B)
Containerized shrubs or those sold balled and burlapped (B&B) offer a much wider planting window due to the protection around their root systems. Container-grown plants can be planted successfully well into late spring or early summer because their roots are intact and surrounded by soil. This flexibility requires consistent watering after planting to prevent the root ball from drying out in warmer weather. The presence of the soil minimizes transplant shock, allowing for a more forgiving schedule.
Adjusting Timing for Regional Climate Zones
The terms “spring” and “fall” are relative and must be interpreted based on the local climate, often referenced using the USDA Plant Hardiness Zones. These zones categorize regions based on the average annual minimum winter temperature.
Cooler Climates (Lower USDA Zones)
Gardeners in Northern or cooler climates often prefer spring planting. This preference gives the shrub’s root system the longest possible period to establish before facing a long and harsh winter.
Warmer Climates (Higher USDA Zones)
In Southern or warmer climates, the fall planting window is frequently considered superior. The mild winters in these regions allow for continuous, slow root development throughout the cool season, avoiding the immediate onset of intense summer heat. Fall planting also capitalizes on reduced water stress when air temperatures are lower and natural rainfall is often more consistent.
Planting During Off-Seasons
Planting shrubs outside of the optimal spring and fall windows—in mid-summer or mid-winter—is possible but significantly riskier and requires increased effort.
Mid-Summer Planting
Mid-summer planting places extreme stress on the newly transplanted shrub due to high temperatures and potential drought conditions. If planting must occur, it requires daily monitoring and watering to prevent the root ball from drying out, sometimes necessitating temporary shading to reduce moisture loss.
Mid-Winter Planting
Mid-winter planting is only viable in regions where the ground does not freeze solid and the shrub is completely dormant. Attempting to plant in frozen ground should be avoided. In areas with freeze-thaw cycles, a major risk is frost heaving, where the expansion and contraction of freezing water can push newly set roots out of the ground. If winter planting is necessary, selecting a containerized shrub and applying a thick layer of mulch can help insulate the soil and protect the roots.