Another one of our top five favorite Herbaceous Peonies for both garden display and cut flower arrangements is Raspberry Sundae. It's a must-grow for decades of beautiful, fragrant perfection.
It's the Bomb
If you and your clients are searching for an incredibly showy, absolutely huge pink double with a soft, sweet fragrance, you needn't look any further. Raspberry Sundae is the best bomb-shaped double ever. Circa 1968, this Klehm hybrid has gigantic 10" pale pink flowers ringed in gold and bursting with an explosive center of pale to raspberry-pink petals that mature to pale whitish-pink.
Raspberry Sundae is incredibly floriferous. As it matures, the plants grow to about 2 1/2' tall and 3' to 4' wide. Blooming on the earlier side of the May/June season in horticultural zone 5, we recommend installing Peony grow-through rings to support the weighty, flower-laden stems. Mere twine can cause stems to snap since the flowers are so big and hefty, particularly after rain has collected on its dense multiple petal layers. As with all Herbaceous Peonies, the foliage remains attractive well after the flowers have faded~it's good for lush greennery all summer long.
Raspberry Sundae is Easily Planted and Grown
Our prized Raspberry Sundae rootstocks have been nursery-grown through division in the Netherlands for two years. Each rootstock has varying amounts of roots, and three to five eyes (or minuscule buds) for optimum flower production the first spring. Some individual rootstocks may be trimmed of old wood to allow room for new root growth.
We receive our Herbaceous Peonies from the annual Dutch harvest in early October. Inspect the roots when you receive them. If they are really dry, you may rehydrate them in room temperature water for up to six hours, although it's not really necessary because they rehydrate once planted. Store the rootstocks in a cool, dark spot until it's time to plant them in October after the soil has cooled to about 55 degrees F, after about two weeks of sweater weather when night time temps have hovered in the 40s.
Peonies love abundant sunshine, well-draining, rich loamy soil, ample breathing room between plants and structural support for their ever-burgeoning, flower-laden stems. They prefer neutral to slightly alkaline pH soil (6.0 to 7.0) although they can handle slightly acidic soil. Prepare the planting site by cultivating 2 feet wide by 1.5 feet deep holes, 3 to 4 feet apart. Fill each hole with 1 foot of good loam. Plant each rootstock so that the crown is just 2 inches below the soil level with the eyes, or sprouts, pointing up. Do not plant them any deeper than that~it could inhibit flower production. One of the most important planting tips is to make sure that they are planted deep enough. If they are not planted to the proper depth, the plant may not flower. Double varieties may bloom as semi-doubles the first year depending on the weather, with more fully double flowers developing as the plants mature.
Carefully shovel loose soil around the rootstock. Install grow-through Peony supports. Water well. After they are planted and after the ground freezes, mulch newly planted rootstocks with sawdust, straw or evergreen boughs to help protect them from temperature spiking. Remove the mulch first thing in the spring before the new sprouts emerge. Mulching is not recommended in subsequent years.
Although they love copious spring showers, Herbaceous Peonies are extremely drought-tolerant once established, maturing into increasingly huge, more floriferous plants over time. They thrive, maintenance-free, for decades, even generations. Each fall, cut down the stalks to within two inches above the ground level and discard all felled cuttings. The cuttings are bad for composting.
Trouble Shooting Client Gardens
Rare failure to bloom is usually due to rootstock crowns planted too deeply. Failure to thrive can be caused by too much shade, poor water drainage, an overcrowded planting site or a late spring killing frost (desiccated buds). If the Peony crown was planted too deeply and needs to be repositioned the next fall, water the rootstock the day before. Dig up the rootball carefully with as little root upset as possible. Rework the soil. Replant the rootball ½ inch higher than the soil level. Water and mulch well~the crown should settle down to soil level.