Overview of Parietaria L.
Parietaria L. is a genus of flowering plants that belong to the nettle family Urticaceae. It comprises approximately 16-17 species of annual, biennial or perennial herbs which are commonly known as pellitories, which are distributed in temperate regions of the Northern Hemisphere, Africa, and South America. The plant is characterized by its small, greenish flowers and nettle-like leaves. Parietaria has several uses in traditional medicine, including as an anthelmintic, a diuretic, and a treatment for respiratory complaints.
Appearance and Characteristics
The plant's leaves are alternate and simple, without stipules, usually sessile and often with a decurrent base, with an ovate-lanceolate shape, serrate margins, and a slightly pubescent texture. The plant grows between 20 and 80 cm high, with a taproot or fibrous roots, and its branch is angular and ribbed. The flowers are small and arranged in axillary or terminal spike-like inflorescences, with inconspicuous greenish petals and five stamens. The fruit is a small dry achene containing one seed.
Common Names
Parietaria has several common names that include pellitory, parietary, wall pellitory, and clearweed, and the local names vary depending on the region.
Uses
Parietaria has several medicinal uses in traditional medicine. It has been used as an anthelmintic to treat intestinal worms, as it is believed to have properties that expel parasites from the body. It is also used as a diuretic and is thought to increase urine output, which helps to remove excess fluids from the body and reduce swelling. Parietaria has been used to treat bronchitis, asthma, and other respiratory complaints due to its anti-inflammatory properties. It is believed to help reduce inflammation of the lungs and improve breathing. The plant also has antihistamine and anti-allergic properties and may be useful for reducing the symptoms of allergies such as hay fever.
Growth Conditions for Parietaria L.
Parietaria L. is a small flowering plant that belongs to the Urticaceae family. It is common in many parts of the world, including Europe, Asia, Africa, and North America. The plant is mainly found in urban environments, including walls, pavements, and disturbed soils. It has a fast growth rate, and it can quickly colonize large areas, especially in areas with human activities.
Light Requirements
Parietaria L. requires moderate to high light intensity to grow well. The plant can tolerate partial shade, but too much shade can cause it to grow weak and leggy. It is best to plant Parietaria L. in an area where it can receive at least 6 hours of direct sunlight per day. In areas with high temperatures, the plant may benefit from partial shade during the hottest part of the day.
Temperature Requirements
Parietaria L. is adapted to temperate to subtropical climates, and it can tolerate a wide range of temperatures. The plant can withstand temperatures as low as -10°C and as high as 40°C. However, it grows best in temperatures between 18°C to 25°C. In areas with extreme temperatures, it is best to plant Parietaria L. in an area with partial shade to protect it from the excessive heat or cold.
Soil Requirements
Parietaria L. can grow in a wide range of soil types, including clay, sandy, loamy, and rocky soils. The plant prefers well-draining soils with a pH range of 6.0 to 7.5. It can tolerate slightly acidic or alkaline soils. However, in areas with poor drainage, it is best to amend the soil with organic matter such as compost or aged manure to improve water retention and aeration.
Cultivation methods
Parietaria L. is generally easy to grow and does well in a variety of soil types, including dry and rocky soils. It benefits from full sunlight but can also tolerate partial shade. Seeds can be sown directly outdoors in the spring and summer months when the soil temperature is around 18-20°C. The seeds should be placed approximately 1 cm deep and spaced 15-20 cm apart. Alternatively, young plants can be transplanted into the garden from late spring onwards.
Watering needs
During the growing season, Parietaria L. should be watered regularly to keep the soil moist but not waterlogged. This is particularly important during dry spells or in excessively hot weather. It is also important to avoid getting water on the leaves, as this can increase the risk of fungal diseases.
Fertilization
Parietaria L. typically does not require additional fertilizer beyond what is provided by the surrounding soil. However, if the plant is growing in poor soil or appears weak, a general-purpose fertilizer can be applied in spring, followed by a second application in mid-summer. Care should be taken not to apply too much fertilizer, as this can result in excessive growth and may reduce the plant's overall vigor.
Pruning
Although Parietaria L. does not require regular pruning, it may benefit from occasional maintenance to encourage bushy growth and prevent leggy or straggly stems. Pruning should be carried out in late winter or early spring, before the new growth appears. Any damaged or dead stems should be removed, and the remaining stems can be lightly pruned to shape the plant.
Propagation of Parietaria L.
Parietaria L. commonly known as pellitory is a herbaceous plant that belongs to the Urticaceae family. This plant can be propagated through two methods, namely:
1. Seed propagation
Seeds are a common means for propagating parietaria. The ideal time for sowing seeds is in the spring. The first step in seed propagation is to choose a growing medium that is rich in organic matter. Sow the seeds lightly, covering them with a thin layer of soil or vermiculite. The soil should be kept moist until the pellitory germinates.
The young plants should be transplanted into individual pots once they have developed two to four true leaves. Pellitory should be grown in a light, airy position, with protection from direct sunlight and frost. They can be planted outside when they are strong and have developed a good root system.
2. Cutting propagation
Another means of propagating parietaria is through cuttings. This method can be used at any time of year but is most successful in the spring when the plant is producing new growth. The stems should be cut from the parent plant, making sure that they are free from pests and diseases. The cuttings should be 7 to 10 cm long, with a diameter of about 3 mm.
Once cuttings have been taken, the lower leaves should be removed, and the stem placed in water for several hours to prevent wilting. The cuttings should then be dipped in rooting hormone powder and placed in a pot of moist sand or vermiculite. The pot should be kept in a warm, well-lit position, but out of direct sunlight. After a few weeks, roots should begin to form, and the cuttings can be transplanted into individual pots.
Disease Management for Parietaria L. plant
The Parietaria L. plant is generally a healthy and hardy plant, with a low susceptibility to diseases. However, when the plant is under stress, it can become vulnerable to common plant diseases, such as fungal infections, powdery mildew, and rust.
To manage fungal infections, it is recommended to avoid overhead irrigation, prune affected areas of the plant, and use a fungicidal spray according to the package instructions.
Powdery mildew can be managed by maintaining proper air circulation around the plant, removing infected leaves, and using a suitable fungicidal spray.
Rust is a fungal disease that causes orange, yellow, or red discoloration on the leaves of the plant. To manage rust, it is recommended to prune affected areas of the plant and dispose of them, avoid overhead irrigation, and use a fungicidal spray regularly.
Pest Management for Parietaria L. Plant
Pests are another common issue that can affect the Parietaria L. plant, such as aphids, spider mites, and whiteflies.
Aphids can be managed by using a strong spray of water to dislodge them from the plant. Alternatively, neem oil or insecticidal soap can be used according to the package instructions.
Spider mites are tiny pests that can cause a lot of damage to the Parietaria L. plant, including wilting, leaf drop, and discoloration. To manage spider mites, it is recommended to increase humidity around the plant, remove affected leaves, and use insecticidal soap or neem oil according to the package instructions.
Whiteflies can be managed by using yellow sticky traps, which attract and trap the pests. Neem oil or insecticidal soap can also be used according to the package instructions.
Regularly inspecting the Parietaria L. plant and keeping it healthy by providing adequate sunlight, water, and fertilization can also help prevent and manage pests and diseases.
