When is the absolute best time to plant shrubs?
Written by
Michael Sullivan
Reviewed by
Prof. Martin Thorne, Ph.D.Identifying the best time of year to plant shrubs can significantly affect your gardening success. In all climates and for all plant types, the autumn months always outperform the other seasons. Warm soil temperatures promote active root growth, and cooler air temperatures reduce stress on the plants. This phenomenon can create the perfect environment for the establishment of the plants before they enter winter dormancy.
Soil Preparation
- Test drainage with water-filled hole method before planting
- Amend soil with 3:1 native soil to compost ratio
- Ensure pH between 6.0-7.0 for most shrubs
Root Management
- Tease circling roots gently with fingers
- Trim damaged roots at 45° angle with sterilized pruners
- Soak bare-root plants 1-2 hours before planting
Post-Planting Care
- Apply 2-3 gallons water immediately after planting
- Maintain 3-inch mulch ring away from stems
- Monitor for frost heave weekly during freeze-thaw cycles
Soil warmth in the autumn is essential for roots to establish. Quartzo 28-36° b, follows summer temperatures, the soil in the fall/early spring (the soil retains summer temperatures longer than the air cools), and when the roots are in a temperature zone of 10-21° cooling, the root regaining energy is diverted into foliage. Hydrangeas established in the October spring or further hydrangeas established in early fall are typically greener in the spring than a plant in April.
Regional differences dictate planting windows. Northern areas should try to finish before the frost. Southern reaches should be able to extend planting until November. All of this can be monitored using a thermometer to measure soil temperature performance. I adjusted all of this year's dates to the next year, depending on the frost dates in my area.
Container plants still retain the advantages of being planted in the autumn. Container plants are more flexible than in-ground planting; they establish faster when cool-season planting occurs. Just avoid extreme temperatures below 25°F (-4°C) or above 95°F (35°C). My potted azaleas transition the best when they are moved in October.
Read the full article: When to Plant Shrubs: Complete Guide
