White meadowsweet (Spiraea alba) is a perennial shrub that grows from 91 to 183 cm tall. Pyramidal clusters of fragrant white or pink flowers blossom from summer through fall attracting butterflies and birds. Brown fruit appears after blossoms fall off. Grows well in sunny or partly shady locations.
I. Appearance and Characteristics
Spiraea alba, commonly known as meadowsweet, white meadowsweet, narrowleaf meadowsweet, pale bridewort, or pipestem, is native to the wet soils of the Allegheny Mountains and other portions of eastern North America, but is currently endangered in the state of Missouri. It is naturalized in other parts of the world.
Narrowleaf meadowsweet shrubs often reach 8 feet in height with a spread of 3–4 feet. This species is often the most conspicuous part of the vegetation in its habitat, taking up large areas of ground. Its leaves are glossy yellow-green, oblong or lance-shaped, and toothed on the edges, and its twigs are tough and yellowish brown. Fall foliage is golden yellow. The white and sometimes pink fragrant flowers grow in spike-like clusters at the ends of the branches, blooming from early summer through September. The brown fruit, which persists after flowering, is a distinctive feature of all Spiraea species.
Butterflies and other beneficial insects visit the plant for nectar and pollen. In autumn brown seed capsules appear and are fed on by songbirds. Glossy green foliage turns yellow in the fall. Deer tend to leave this plant alone. Meadowsweet is a host plant for the larvae of the spring azure butterfly (Celastrina argiolus).
II. How to Grow and Care
Sunlight
White meadowsweet needs sufficient light. The more sunlight, the more lush its blossoms. It can put up with short periods of shade, but overly shady environments weakens the photosynthesis process and reduces growth, leading to fewer blossoms and smaller, thinner leaves. The leaves of the variegated variety can lose color and turn green. Space plants 60 to 80 cm apart from each other in order to avoid blocking each other’s sunlight as mature plants.
Temperature
White meadowsweet originated in the temperate and subtropical mountains of the Northern hemisphere. It grows best in regions with distinct four seasons. It’s best grown in temperatures between 10 to 25 ℃ , but can survive as cold as -20 ℃. Besides its excellent cold resistance, it’s also drought- and humidity-tolerant.
Watering
Originating from moist meadowlands, white meadowsweet thrives in environments that mimic its native damp conditions. It has a moderate tolerance for drought but flourishes when the soil remains consistently moist without being waterlogged. Watering should occur once every week to maintain this balance. As an herbaceous perennial commonly grown outdoors, white meadowsweet benefits significantly from rainwater during its active growing season, which aligns with its natural preference for pluvial conditions.
Soil
White meadowsweet can grow in barren, saline-alkali soil. It doesn’t require anything specific from the soil, which means you can use all-purpose garden soil. It likes sandy soil that is loose, permeable, and rich in organic matter, but can also live in loamy clay soil. If your region gets a lot of rain, mix 3 parts garden soil and 1 part river sand or perlite to improve the soil’s permeability and water drainage. It grows best in soil with a pH value at 7, a.k.a. neutral soil.
Fertilizing
Fertilize white meadowsweet in spring with a balanced fertilizer to support vigorous growth and optimal flowering. A high-nitrogen formula can be used if foliage growth is poor. Apply the fertilizer as per product instructions, avoiding over-fertilization which can harm white meadowsweet. Reduce feeding frequency as white meadowsweet enters dormancy in fall. Always water white meadowsweet thoroughly after applying fertilizer to help nutrient absorption and prevent root burn. For continual health, adjust fertilization with the seasons and white meadowsweet’s developmental stage.
Planting Instructions
Pruning
Prune between the end of winter and early spring to trim overlapping, withered, or pest/disease-infested branches. If white meadowsweet gets too large, doesn’t have enough growing space, or looks less attractive, prune it severely. Its ability to sprout new branches is relatively strong, and flowers only bloom on new branches. Therefore, there is no need to worry that hard pruning may negatively affect its growth or bloom.
After blooming, cut off the branches that flowered to avoid unnecessary nutrition consumption. This encourages new branches to sprout and prepare to flower. Cover incisions with callus anticorrosion film to encourage healing and prevent bacterial infection.
Propagation
White meadowsweet is best propagated during autumn and winter using cutting and layering techniques. It has a moderate level of propagation difficulty. Successful propagation is indicated by new growth and roots. Provide consistent moisture for optimal results.
Transplanting
The best time to transplant white meadowsweet is autumn to early winter, as the plant is in dormant state, offering a high success rate. White meadowsweet prefers a sunny spot, with good draining soil. Be gentle during the transplant process, avoiding root damage to ensure its healthy growth.
Repotting
The white meadowsweet, a bushy shrub, thrives when repotted every 2-3 years to support its growth. Ideal repotting occurs in early spring, coinciding with its recovery from dormancy. Choose a pot slightly larger than its root ball to encourage expansion. Post-repotting, ensure well-draining soil, consistent moisture, and partial sunlight exposure. Regular pruning maintains shape and promotes new blooms for this graceful plant.
III. Uses and Benefits
- Ornamental uses
The high tolerance for boggy soil conditions of white meadowsweet makes this shrub a suitable choice for establishing on the edges of ponds and streams in large garden landscapes. In addition, the attractive clusters of the white, summer-blooming flowers on this plant provide visual interest when grown as a hedge or border in a cottage garden.
- Other uses
The blooms make a good cut flower.
The hollow, upright stems were used historically as pipe stems.
IV. Harvesting and Storage
White meadowsweet’s branches, leaves, and flowers are all highly ornamental and often used in bouquets. After harvest, cut the base of the flowering twigs at a 45° angle with a pair of sharp gardening scissors to maximize the water absorption surface. Place the twigs into a vase filled with clean water quickly to avoid water loss. Cut flowers can last 7-10 days.