Why is fall considered better than spring for some perennials?
Written by
Michael Sullivan
Reviewed by
Prof. Samuel Fitzgerald, Ph.D.Planting in the fall can provide unique benefits to many perennials because of the custom soil and temperature conditions. The heat retained in the soil from summer allows roots to develop well, while the cooler air reduces stress on the leaves. The combination provides the best establishment conditions for roots and leaves that spring can't offer. I have seen plants flourish when moved or planted in the fall.
Soil Preparation
- Test soil temperature: Ideal range 45-60°F at 6" depth
- Mix 3" compost to retain summer warmth
- Adjust pH to 6.5-7.0 for nutrient availability
Plant Selection
- Choose cold-hardy varieties with vernalization needs
- Prioritize early-blooming species over late-season types
- Select container-grown plants over bare-root for faster establishment
During the fall, when the soil is warm, root development speeds up without the utilization of foliage shoot energy. This means plants are putting their energy and resources underground and developing strong root systems. Therefore, by spring, peonies planted in the fall will have a root system that is 30% larger than those grown in spring. My fall-planted peonies consistently exceed my spring-planted peonies.
With lower heat stress, plants are allowed to establish without wilting or scorching the vegetation. There is lower transplant shock when transplants are performed at air temperatures of 45-60°F. With automatic rainfall, water needs are reduced. These conditions create a less expensive establishment. I suggest falling to gardeners in hot climates.
Vernalization requirements make fall vital for many early bloomers. Plants such as hellebores and bleeding hearts require a chilling period to induce spring blooming. Their biological clocks are influenced by winter dormancy. Planting in the fall coincides with their biological cycles for dependable blooming.
Use post-planting care to ensure benefits. Water weekly until the ground freezes, then add protective mulch after the first hard freeze. Refrain from fertilization, because tender growth will be more susceptible. These practices will enable plants to enter dormancy properly, ensuring optimal performance in the spring.
Timing within zones creates success. Northern gardeners should plant only 6-8 weeks in advance of the first frost. In southern zones, fall planting extends until November. Use the garden soil temperatures, not calendar dates. It's the exactness of your garden soil temperatures that distinguishes between triumph and tragedy for your fall crops.
Read the full article: When to Plant Perennials: Expert Guide
