Peony ‘Bartzella’ is a beautiful peony considered by many to be the most perfect yellow-flowered of all the peonies. Bred by Roger Anderson, it is named for a friend of his. This intersectional peony is large than native peonies and features uniquely colored flowers, ideal for a landscape plant.
I. Appearance and Characteristics
With an above-average blooming ability, award-winner Itoh Peony ‘Bartzella’ features very large and luminous, golden yellow, semi to fully double flowers, 6-8 in. wide (15-20 cm), delicately flushed scarlet at their heart. Borne in profusion (expect 30 blossoms the first year and over 60 on a mature bush!), they are well presented above the foliage, on strong, erect stems that do not require staking. This late midseason peony will flower in late spring – early summer for 3-4 weeks thanks to the many side buds which open in sequence. As a bonus, this Itoh peony is fragrant with a lovely lemon scent.
II. How to Grow and Care
Sunlight
Peony ‘Bartzella’ needs sufficient sunlight and is resistant to partial shade, but cannot tolerate blazing sunlight. It needs shade in hot summer weather so the leaves won’t get a sunburn. It is suitable for planting at sites where the tree crown can provide suitable shade at noon. It can be planted among shrubs.
Temperature
Peony ‘Bartzella’ likes a cool environment; it is suitable for planting in cold climates and high latitudes. It can overwinter at low temperatures. The temperature for growth is above 0 ℃, and the optimum temperature for growth is 16 to 18 ℃. When the temperature is higher than 25 ℃, it becomes dormant. It must experience 2-3 months of low temperatures (1 to 10 ℃) before blooming. The best temperature for blooming is 17 to 22 ℃. Peony ‘Bartzella’ is resistant to drought, but accumulated water is fatal.
Watering
Thriving in its native lush environment, peony ‘Bartzella’ has adapted to regular hydration cycles. This species is characterized by a preference for consistent moisture, aligning with its origins in regions of ample rainfall. Watering should occur once every week to maintain this balance and support the plant’s health. Given that peony ‘Bartzella’ is often cultivated outdoors due to its robust nature, it’s important to consider how natural precipitation can supplement irrigation practices, especially during the active growing season when water demand peaks.
Soil
Peony ‘Bartzella’ needs loose and deep culture medium with sufficient nutrients and good drainage. The suitable soil pH is 6.5-7; peony ‘Bartzella’ will grow poorly in acidic and sticky soil. Select the loose, breathable peat as the culture medium, add coarse sand to improve air permeability and drainage, and add garden soil and organic matter so the medium retains enough water but does not accumulate it.
The recommended culture medium ratio is 1/3 peat + 1/3 coarse sand + 1/3 garden soil. Sterilize the culture medium before transplanting; sunlight combined with medical treatment is generally adopted.
Fertilizing
Peony ‘Bartzella’ likes fertilizer, and nutrition affects the quantity and quality of flowers. Besides the basic fertilizer applied when transplanting, three applications of fertilizer are required every year. Before the first watering in the early spring, when the branches, leaves, and buds grow.
About 15 days after the flowers wither. Appropriate amounts of fertilizer promote flower bud differentiation and improve the plant’s resistance.
In fall and winter, the application of organic fertilizer provides nutrients for plant growth in spring and builds some cold resistance.
Apply fertilizer in a ring. Dig a ring of shallow ditches 5 to 10 cm deep around the edge of the plant crown. Apply the fertilizer evenly in the ditch and water. Loosen the soil after it dries.
There are three things to avoid in peony ‘Bartzella’ fertilization. Firstly, do not apply high-concentration fertilizer, which causes fertilizer damage. Secondly, do not apply fecal water, which causes diseases (soybean meal or rapeseed meal is recommended as organic fertilizer). Thirdly, do not apply fertilizer in summer. Growth slows or stops in hot weather, and applying fertilizer at this point of time can easily cause damage.
Planting Instructions
Plant peony ‘Bartzella’ in fall when the roots have stored a large amount of nutrients. After transplanting, the damaged root can continue to grow, and this is beneficial for seedling restoration. Plant 41 to 51 cm deep with a 36 cm diameter. When peony ‘Bartzella’ is planted in flowerpots, the pot should be the same size. Cover with 2.5 to 4 cm of sterilized, sandy loam. In severely cold zones, cover the planting pit with 20 cm-thick soil to ensure healthy overwintering.
Pruning
Pruning is important to maintain a good shape and increase nutrition distribution to flowers and fruits. The sprouts at the root sprouting parts consume too many nutrients from the plant in spring. If they are not pruned, they will impact not only the appearance, but also the ventilation, sunlight, blooming, and fruiting of the plant. They should be pruned as early as possible.
New branches should be pruned in spring when they are roughly 5 cm long; keep 1-2 sprouts in one direction. To prune older branches, leave 2-3 buds and don’t keep too many flower buds; otherwise, they’ll take too much nutrition, resulting in smaller flowers prone to dropping.
Propagation
Peony ‘Bartzella’ thrives when propagated through division, a process which invigorates the plant’s growth and health. To propagate peony ‘Bartzella’, carefully lift the plant from the soil during its dormant period. Use a sharp, sterilized tool to divide the root ball, ensuring each section has at least three to five eyes, which are the growth points, for optimal development. Replant each division promptly to minimize transplant shock, in well-draining soil enriched with organic matter, ensuring proper spacing to accommodate future growth.
Transplanting
The perfect timing to relocate peony ‘Bartzella’ is when autumn whispers to winter, promoting robust spring growth. Choose a sunny spot with well-drained soil. If needed, amend the soil, ensuring a seamless transition for peony ‘Bartzella’.
III. Uses and Benefits
Very useful and adaptable in the garden. Peony ‘Bartzella’ is perfect as a specimen plant and in groups for borders and beds, city gardens, or cottage gardens. Ideal for bordering a walk or driveway and as an informal hedge. Plant your peonies away from trees or shrubs as peonies don’t like to compete for food and moisture. The enchanting peony flower combines beautifully with roses, bearded irises, and other perennials in striking color combinations.
IV. Harvesting and Storage
Peony ‘Bartzella’ blooms in early summer. Harvest cut flowers when the buds are mature and will bloom soon. The best time to harvest peony ‘Bartzella’ is in the morning after dew evaporates, or in the evening. If dewy flowers are cut, the cutting site is prone to pests and diseases. The evening is best because the plant accumulates more carbohydrates at this time.
Use clean, sharp gardening scissors to cut the flower. Cut near the base, but leave 1-3 pairs of leaves on the plant to ensure future growth. Remove any ants and aphids from the cut part. Cut the base at 45º, remove 1/3 of the lower leaves from the stem, and soak the harvested stalk in cool, clean water as soon as possible to avoid water loss.