Tips from the W.E. Upjohn Peony Garden
The W.E. Upjohn Peony Garden at Nichols Arboretum got its start in 1922 and has expanded over the last century to become what is now the largest collection of historic peonies in the world. With nearly 800 peony plants in our care, we’ve learned a lot about what it takes to help peonies thrive. Here are some of the tried-and-true tips we use to keep our plants healthy, beautiful, and resilient year after year.
When establishing new peonies, we recommend that you water deeply and consistently during the first growing season. We focus our watering at the base of the plants near the drip line, the outer edge of the foliage, rather than over the leaves. This encourages strong roots and helps prevent leaf disease. After the first year, water only as needed during drought or extreme heat.
Peony blooms are glorious but heavy. Without support, their stems often bend or collapse under the weight, especially after rain. At the W.E. Upjohn Peony Garden, we use bamboo stakes and soft garden twine to keep them upright. Early in the season, before buds open, we place stakes around the perimeter of each plant. Then, we tie twine from stake to stake, creating a supportive ring or corral that gently holds the stems upright as they grow. This low-profile method blends into the garden and has reliably protected our historic plants for decades. Other support options include metal cages or grow-through rings, which can offer more structured support for home gardeners with fewer plants.
Throughout the bloom period, we deadhead spent flowers to keep the garden looking its best and help plants focus energy on their roots. In the fall, we cut stems down to the ground and remove all plant debris to reduce the chance of disease carryover into the next year.
At the W.E. Upjohn Garden, we don’t use herbicides or fungicides. Instead, we rely on recommended best practices like proper spacing to allow for air flow and trimming maintenance to keep our plants healthy. With the right conditions, peonies can thrive with minimal fuss.
Peonies don’t need to be divided regularly, but if you’re looking to share plants, expand your garden, or rejuvenate an older clump, fall is the best time to divide them. Herbaceous peonies grow from tubers, underground roots that store nutrients and produce new growth each spring. This makes them easy to divide and share.
To divide a mature plant, wait until it has gone dormant in the fall. Carefully dig around the root system, lift the plant, and gently remove soil to expose the crown. Look for firm sections with two or three pink buds (often called “eyes”). Using a clean, sharp knife, cut away a section of the crown with attached roots and buds. These divisions are surprisingly lightweight and tolerate some drying out, which has helped peonies spread successfully across continents and generations.
Despite your best efforts, peonies may still face a couple of common issues. Here’s how we handle them.
Botrytis Blight: This springtime issue shows up in cool, damp conditions and causes the plant’s shoots to brown and collapse. You might notice gray, fuzzy mold on stems or buds. Remove and discard affected parts immediately (never compost them!). Good spacing and avoiding overhead watering can help prevent outbreaks.
Powdery Mildew: Later in the season, you might see a white, powdery coating on leaves. While typically just cosmetic, it can weaken the plant over time. Promote good airflow by spacing plants well, avoid wetting foliage during watering, and cut all stems to the ground at the end of the season to reduce recurrence.
Ants: No problem! Ants on peony buds are normal. They’re attracted to the sugary nectar but do not harm the plant. Every spring, we see ants busily working over the buds in the Upjohn Garden. There is no need to spray or interfere. Once the blooms open, the ants typically move on.
Peonies are resilient, rewarding plants with deep roots in garden history. With a little attention and some hands-on care, they’ll reward you with decades of spectacular bloom. We feel lucky to be part of their story through the W.E. Upjohn Peony Garden and hope these tips help you enjoy them as much as we do.
