What Makes Persicaria So Special?

Persicaria offers a combination of attractive foliage, often with interesting markings or colors, and distinctive flower spikes that add vertical interest to the garden. Many species are quite adaptable and easy to grow, providing long-lasting color and texture. Some varieties have a strong architectural presence, while others have a more relaxed, cottage-garden feel. It is the variety within the genus, combined with their generally easy-going nature (with some important exceptions!), that makes them special. However, like Oxalis, it is crucial to be aware of the invasive potential of some species.

Description

• Growth Habit: Varies depending on the species. Some are low-growing and spreading, while others are tall and upright. Some are clump-forming, while others spread by rhizomes.
• Height: Ranges from a few inches to several feet tall, depending on the species.
• Foliage: Leaves are usually lance-shaped or oval, and they can be green, red, purple, or variegated. Some species have distinctive chevron markings (V-shaped patterns) on the leaves.
• Flowers: Small flowers are borne in dense spikes or clusters, often held above the foliage. Flower colors include pink, red, white, and sometimes greenish.

Details Gardeners Care About

• Sunlight: Varies depending on the species. Some prefer full sun, while others prefer part shade.
• Soil: Generally, prefers moist, well-drained soil that is rich in organic matter. Some species tolerate drier conditions.
• Water: Most species prefer consistent moisture, but some are quite drought-tolerant once established.
• Hardiness: Varies depending on the species. Many are hardy in USDA zones 4-8, but some are more tender.
• Invasiveness: Very important! Some Persicaria species can be aggressively invasive, spreading rapidly by rhizomes or seeds. Research the species carefully before planting.
• Deer Resistance: Generally considered deer-resistant.
• Attracts Pollinators: The flowers attract bees, butterflies, and other pollinators.

Native Habitat Persicaria species are found worldwide, in a variety of habitats:

• Moist meadows
• Wetlands
• Along streams and rivers
• Woodlands
• Disturbed areas

Landscaping Design Tips

• Borders: Many species are excellent for mixed borders, adding height, texture, and color.
• Cottage Gardens: Their often informal habit makes them a good fit for cottage gardens.
• Water Gardens: Some species are suitable for planting around ponds or in boggy areas.
• Groundcover: Some low-growing species can be used as a groundcover (be mindful of invasiveness).
• Containers: Some of the more compact varieties can be grown in containers.
• Cutting Gardens: The flower spikes can be used in cut flower arrangements.
• Mass Plantings: Works well as a mass planting.

Planting and Care

• Planting Time: Spring or fall.
• Spacing: Space plants according to their expected mature size.
• Planting Depth: Plant at the same depth they were growing in their nursery pots.
• Watering: Water regularly, especially during dry periods, but avoid overwatering.
• Mulching: Mulch can help retain moisture and suppress weeds.
• Fertilizing: Generally, does not need much fertilizer. A light application of compost or a balanced fertilizer in spring can be beneficial.
• Deadheading: Deadheading (removing spent flowers) can prolong the bloom period and prevent self-seeding (if desired).
• Pruning: Cut back the plants after flowering to encourage bushier growth and prevent them from becoming leggy. Some species benefit from being cut back hard in late winter or early spring.
• Division: Many species can be propagated by division in spring or fall.
• Controlling Spread: If you have an invasive species, be vigilant about removing unwanted plants and preventing them from spreading.

Taxonomy (Simplified)

• Genus: Persicaria (formerly often included in the genus Polygonum)
• Family: Polygonaceae (Buckwheat family)
• Common Species (Examples):
• Persicaria amplexicaulis (Mountain Fleece) - A popular, clump-forming species with long-lasting flower spikes.
• Persicaria microcephala 'Red Dragon' - Grown for its striking purple-red foliage with silver markings.
• Persicaria virginiana (Virginia Knotweed, Jumpseed) - A native North American species with interesting seed dispersal (the seeds "jump" when touched).
• Persicaria affinis (Himalayan Knotweed)

Morphology (Simplified)

• Stems: Often reddish, sometimes jointed (hence the name "knotweed").
• Leaves: Alternate, lance-shaped or oval, sometimes with distinctive markings.
• Flowers: Small, borne in dense spikes or clusters (racemes or panicles).
• Roots: Can be fibrous roots or rhizomes, depending on the species.
• Fruit: A small, dry achene (a type of one-seeded fruit).
• Ocrea A defining feature of this family, a sheath around the stem at the base of the leaf stalk

Other Insights

• Invasiveness (Crucial!): As with Oxalis, the potential for invasiveness is a major consideration with Persicaria. Some species, like Persicaria capitata (Pink Knotweed) and others, can be extremely aggressive. Research thoroughly before planting.
• Name Change: Many plants formerly classified as Polygonum are now classified as Persicaria. This can be confusing, so be aware of both names.
• Variety: There is a great deal of variety within the genus, with different species offering different foliage colors, flower colors, and growth habits.
• Wildlife Value: Provides habitat for wildlife

In conclusion, Persicaria offers a range of attractive and adaptable plants for the garden, with interesting foliage and long-lasting flower spikes. However, the potential for invasiveness in some species is a serious concern. Choose your species very carefully, be aware of its growth habits, and be prepared to manage its spread if necessary. If you select a well-behaved species and provide the right conditions, Persicaria can be a valuable addition to your garden, providing color, texture, and vertical interest.