One of the key projects in the Rhododendron Dell in spring last year was the renovation of the Peony Border at the south end of the Cherry Walk. Straggly old witch hazels were removed, the border widened, a new selection of herbaceous perennials planted and some of the peonies rearranged.
Among the peonies was a small, self-sown specimen of Paeonia delavayi that had appeared at the back of the border under the shade of Magnolia doltsopa. At that stage, it was little more than a cluster of stems about 50cm tall, with a few leaves attached. Now, after being shifted to the front of the border, where it has more light, better soil and improved drainage, it has at least doubled in size.
Peonies thrive in any moist, fertile soil, whether acid or alkaline, but good drainage is important, particularly for the shrubby types such as P. delavayi. The dramatic increase in size shows just how well struggling peonies can respond to improved soil conditions. Now that it is growing happily, it will mature into a wide spreading shrub up to about 1.6m tall, but if necessary, can be pruned hard to control any intrusion on neighbouring plants.
Not only has the Peony Border specimen increased in size, but it has also begun flowering quite freely.
Compared to other shrubby peonies, P. delavayi has relatively small flowers, but they are a deep red and, along with the smoky-coloured new foliage, look like hot coals. For me, this makes this peony the one to plant.
- Doug Thomson is curator of the Rhododendron Dell at Dunedin Botanic Garden.
