Persicaria capitata: A Complete Guide to Growing and Cultivating

Persicaria capitata, a perennial herbaceous plant of the Polygonaceae family, typically grows 10 to 15 centimeters tall. Its stems are prostrate.

The leaves are ovate or elliptical, with pointed tips and wedge-shaped bases, the edges are entire, and sometimes feature dark brown crescent-shaped spots on the surface.

The plant has globular inflorescences with pale red flowers and elongated, ovate achene fruits. The flowering season spans from June to September, with the fruiting period from August to October.

Persicaria capitata

Capitate Knotweed is indigenous to the Southwest region of China and is also found in India, Nepal, and Myanmar. It grows on mountain slopes and valley wetlands at altitudes ranging from 600 to 3,500 meters.

It favors sunlight, tolerates shade, thrives in warm and humid climates, enjoys moisture, withstands drought, and is not particular about soil types. It can be cultivated through seeding or stem cutting propagation.

The whole plant of Capitate Knotweed is pharmacologically active. It has a bitter and spicy flavor with a cooling effect.

It is known for its heat-clearing, diuresis-promoting, blood-invigorating, and pain-relieving properties; it is used to treat bruises, blood in urine, urinary dribbling, and festering sores.

Persicaria capitata

With its striking flower color and robust coverage, Capitate Knotweed is an excellent choice for ornamental foliage and flower ground cover. It can also serve as a filler in flower beds or as an embellishment in rock gardens.

I. Morphological characteristics

Perennial herbaceous plants with creeping, clustered stems that become woody at the base. Nodes root, internodes shorter than leaves, with multiple branches and sparse glandular hairs or nearly glabrous.

Annual branches are nearly upright with longitudinal ridges and sparse glandular hairs. Leaves are ovate or elliptical, 1.5 to 3 cm long and 1 to 2.5 cm wide, with pointed tips, wedge-shaped bases, smooth margins, and glandular hairy edges.

Surfaces are sparsely glandular hairy, sometimes with blackish-brown crescentic spots. Petioles are 2 to 3 mm long, sometimes with stipules at the base; ocrea is tubular, membranous, 5 to 8 mm long, loose, glandular hairy, with a truncate top and ciliate margins.

The inflorescence is capitate, 6 to 10 mm in diameter, solitary or paired, terminal; peduncle is glandular hairy. Bracts are long-ovate, membranous.

Flowers have very short pedicels; perianth is deeply 5-lobed, pale red, with elliptical segments 2 to 3 mm long. There are 8 stamens, shorter than the perianth; 3 styles are fused at the middle and lower parts, nearly as long as the perianth; stigmas are capitate.

The achene is long-ovate, with 3 edges, 1.5 to 2 mm long, dark brown, densely dotted, slightly glossy, enclosed in the persistent perianth. Blooms from June to September, fruits from August to October.

II. Growing Environment

Persicaria capitata is a mesophyte that thrives in shady, moist habitats. It is highly adaptable and cold-tolerant, generally growing at elevations of 600 to 1500 meters.

With a growing season of 210 days, it can also thrive in poor soils. The optimal temperature range for its growth is 15 to 28 degrees Celsius.

III. Distribution Range

Capitatum Persicaria originates from the southwestern region of China and is also found in Northern India, Nepal, Sikkim, Bhutan, Myanmar, and Vietnam.

It thrives on mountain slopes and in moist valley lands at altitudes ranging from 600 to 3,500 meters, often growing in large patches.

IV. Propagation Methods

Persicaria capitata can be cultivated through seeding or cutting propagation methods.

V. Cultivation Techniques

Nursery Bed Preparation

Select a location sheltered from the wind and facing the sun, with fertile soil, convenient water sources, and good water and air permeability, such as sandy soil.

Prepare the nursery site in November to December, a year before seeding.

For each standard bed (10 meters long and 1 meter wide), prepare 200 kilograms of stable manure, cover with plastic film for fermentation treatment, and compact for later use; remove debris from the soil intended for the nursery bed, plow deeply to a depth of 20-25 centimeters to overwinter, and plow again 15 days before seeding to fully refine the soil; prepare seeds, ground film, agricultural film, bamboo clips, compound fertilizer, calcium superphosphate, dichlorvos, and compost for future use.

Seeding

The ideal time for sowing is from late February to mid-March. Before seeding, disinfect the soil with a 2000-fold solution of dichlorvos. After watering thoroughly, proceed with seeding.

For each standard bed (10 square meters), first mix 30 grams of seeds with 500 grams of fine soil evenly, then mix with another 2000 grams of fine soil and spread evenly over the bed in three installments. Afterward, insert bamboo sticks and cover with film, pressing down firmly.

Seedlings typically emerge 7-10 days after seeding. Pay close attention to the emergence of seedlings, especially during the 7th to 10th days after seeding.

When about 60% of seedlings are visible, remove the clips and uncover the film, check if the bed requires watering and if not overly dry, delay watering temporarily. Generally, water 4-5 days later, once most of the seedlings have established roots.

Once the seedlings are uniform and the roots are secure, focus on managing the moisture in the nursery bed and weeding.

Plowing and Preparing the Land

After the previous crop is harvested, remove crop residues and weeds. Plow the land to a depth of 25-30 centimeters before the frost to expose some pests to the surface and freeze them, reducing the overwintering pest population.

Before transplanting in April, plow the soil once more to a depth of 20-25 centimeters, combine with land preparation, and apply sufficient base fertilizer—30 tons of decomposed farmyard manure and 300 kilograms of compound fertilizer per hectare incorporated into the soil.

Remove weeds from the field, and form beds 1 meter wide with standard spacing, trenches 30-40 centimeters wide, and beds 10 centimeters high.

After leveling and finely raking the bed surface, it is ready for use. When forming beds, it’s best to orient them east-west on flat land and at an angle on sloped land to prevent soil erosion.

Seedling Transplantation

Lifting Seedlings

From April to May, when the seedlings reach 7-8 leaves and a height of 6-8 centimeters, they are ready for transplantation. One day before transplanting, thoroughly water the nursery bed.

The next day, select seedlings that meet quality standards, gently lift them by the base using the thumb, index, and middle fingers, and place them in a clean bamboo or plastic basket.

Cover them with a damp cloth or fresh grass to retain moisture during transport to the transplanting site. Lift seedlings as needed, ensuring that those lifted on the same day are transplanted that day.

Transplanting

Maintain a planting distance of 25 centimeters by 25 centimeters, aiming for a density of 150,000 plants per hectare. First, stretch a string down the center of the bed and plant one seedling under the string.

Then extend to the left and right sides, keeping a row spacing of 25 centimeters, planting five rows per bed, one plant per hole. After planting, water immediately to establish the roots.

Field Management

Checking and Filling Gaps

Within one week after transplanting, observe the field to check for gaps and replenish seedlings as needed to ensure a solid plant base.

Weeding and Cultivation

Before Persicaria capitata seedlings close the rows in June, weed every 10-15 days using a hoe to stir the soil on the bed surface, remove weeds, improve soil aeration, reduce soil moisture evaporation, and promote root growth.

After the rows are closed until harvesting, weed by hand every 15 days.

Fertilization and Irrigation Management

In early to mid-June, combine soil loosening and weeding with a top dressing of 150 kilograms per hectare of compound fertilizer, evenly distributed around the roots of the young Persicaria capitata plants and covered with soil.

Within three days after the first harvest in August, apply a follow-up fertilization of 300 kilograms per hectare of compound fertilizer at the base of the plant roots, combined with soil loosening to encourage early branching and sprouting from the old stem base.

Persicaria capitata is intolerant of waterlogging, so dig drainage ditches around the planting area to ensure good drainage.

During dry periods, irrigate to prevent drought, being mindful to water generously before the rows close and less so afterward to prevent waterlogging, which could lead to rotten leaves, stems, roots, and a reduction in both yield and quality of the plant material.

VI. Pest and Disease Control

After transplanting, it is crucial to intensify pest and disease control measures, especially since the newly transplanted plants are particularly susceptible to pests such as cutworms and flea beetles.

These pests can cause significant damage and must be addressed promptly. Cutworms can be manually controlled or treated with a 2000-fold diluted solution of 50% Phoxim EC; flea beetles can be managed using a 1500-2000-fold diluted solution of Imidacloprid.

VII. Primary Value

Medicinal Value

The entire Persicaria capitata plant is used in herbal medicine. With its bitter and pungent taste and cool nature, it is known for clearing heat and dampness, promoting blood circulation, and relieving pain. It is traditionally used to treat bruises, hematuria, urinary dribbling, and sores.

Ornamental Value

The vibrant blooms of Persicaria capitata make it an excellent ground cover that adds a splash of color to any landscape. It’s a superb choice for foliage and flowering ground cover, ideal for filling flower borders or accentuating rock gardens.

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