Overview
Lappula squarrosa (L.) Dumort. subsp. heteracantha (Ledeb.) Chater is a plant species that belongs to the borage family Boraginaceae. It is a perennial herbaceous plant that is native to Europe and Asia, and it is widely distributed in many parts of the world. The plant is known for its small blue flowers and the presence of tiny hooked hairs on its seeds and stems.
Common Names
The plant is commonly known as Heteracanthous Stickseed, Stickweed, and Square-stemmed Stickseed.
General Appearance
The plant has a basal rosette of leaves that are up to 15 cm long and 5 cm wide. Its stems are branched and can grow up to 1 m tall. The stems are square in shape and covered in small hairs, and they have a zigzagging appearance due to leaves emerging from different sides at intervals. The plant has small blue flowers that are arranged in inflorescences that coil up as they mature. The fruits are small nutlets, covered in tiny hooked hairs that enable them to stick to clothing or animal fur.
Uses
The plant has been used in traditional medicine as a remedy for various ailments. The root of the plant has been used to treat liver diseases, while the leaves have been applied externally to relieve skin inflammation and arthritis. The plant has also been used as a source of food for livestock and wildlife.
Light Requirements
Lappula squarrosa subsp. heteracantha requires full sun to partial shade to grow properly. It is well adapted to bright light conditions and can tolerate direct sunlight for several hours a day. However, prolonged exposure to extremely bright light may cause the plant to scorch and may stunt its growth. Partial shade conditions offer protection from intense sunlight, which may be beneficial in hot, arid regions.
Temperature Requirements
Lappula squarrosa subsp. heteracantha is an alpine or subalpine plant that grows at elevations ranging from 2000 to 4000 meters above sea level. Thus, it is adapted to cold temperatures and can grow in relatively harsh environments. The ideal temperature range for this plant is between 10°C and 20°C. At temperatures above 25°C, the growth rate may slow down, and the plant may suffer from heat stress and wilting. In contrast, temperatures below 5°C may cause the plant to go dormant.
Soil Requirements
Lappula squarrosa subsp. heteracantha prefers well-drained soils with low to moderate fertility. The plant can grow in a wide range of soil types, including sandy, gravelly, and rocky soils. However, it requires regular watering to maintain healthy growth. The soil pH should be neutral to slightly alkaline, ranging from 6.5 to 8.5. The plant is salt-tolerant and can grow in saline soils. Still, excessive salt concentrations may inhibit its growth and cause damage to the roots.
Cultivation
Lappula squarrosa (L.) Dumort. subsp. heteracantha (Ledeb.) Chater, commonly known as the common stickseed, is a hardy perennial plant that thrives in dry, rocky soils and full sun. It is native to North America and other parts of the world. This plant can be cultivated by sowing seeds directly into the soil or by transplanting the seedlings.
Watering Needs
The common stickseed is drought tolerant and can survive dry periods with little to no watering. However, regular watering is recommended during dry spells to keep the plant healthy and promote better growth. It is important to avoid overwatering the plant, as this can lead to root rot.
Fertilization
The common stickseed does not require excessive fertilization. A moderate amount of nitrogen-rich fertilizer can be applied during the growing season to promote plant growth. Fertilizer should not be applied during the dormant season, as this could damage the roots.
Pruning
Pruning is not necessary for the common stickseed, but it can help control the plant's size and shape. Deadheading the flowers after they bloom can encourage the growth of new flowers. Pruning should be done after flowering to prevent damage to the plant's growth.
Propagation of Lappula squarrosa (L.) Dumort. subsp. heteracantha (Ledeb.) Chater
Lappula squarrosa (L.) Dumort. subsp. heteracantha (Ledeb.) Chater can be propagated through different methods, including seeds and stem cuttings. Each method has its advantages and disadvantages, and the choice depends on the grower and the available resources.
Propagation by seeds
Propagation by seeds is the easiest and most common method of propagating Lappula squarrosa (L.) Dumort. subsp. heteracantha (Ledeb.) Chater. The seeds should be collected in late summer or early fall when the plant has ripe seeds. The seeds should be stored in a cool and dry place until planting time.
Before planting, the seeds should be stratified for a few weeks. This means that the seeds should be kept in a cool place for a specified period to improve their germination. After stratification, the seeds can be planted in well-draining soil. The soil should be kept moist until the seeds germinate, which can take up to several weeks.
Propagation by stem cuttings
Propagation by stem cuttings is another way of propagating Lappula squarrosa (L.) Dumort. subsp. heteracantha (Ledeb.) Chater. This method requires taking stem cuttings from the mother plant and planting the cuttings in well-draining soil. The cuttings should be about 10cm long and should have several leaves.
The lower leaves should be removed, and the cutting should be planted in a pot or directly in the ground. The soil should be kept moist until the cutting roots. This method is not as reliable as propagation by seeds, but it can be useful when seeds are not available. It is important to keep in mind that not all stem cuttings will root successfully, so it is advisable to take more cuttings than necessary.
Disease management
Lappula squarrosa is generally a healthy species that does not suffer from serious diseases. However, under certain conditions, some fungal pathogens may cause damage to the plant, such as:
- Leaf spot: Fungi like Septoria cause small, brown spots on leaves. This disease can lead to defoliation if left untreated.
- Root rot: Caused by Phytophthora and Pythium fungi, root rot leads to wilting, yellowing, and death of young plants.
The most effective way to prevent fungal problems is to ensure excellent cultural practices. Irrigation, drainage, and fertilization should be balanced to help establish healthy plants. Crop rotation every year is a good strategy to minimize the impact of these pathogens. Fungicides may be used to control severe fungal infections, but this should be a last resort.
Pest management
Lappula squarrosa is also relatively free from severe pest problems, but it can be attacked by some insects such as:
- Spider mites: These tiny insects suck sap from the leaves, leaving stippled areas and eventually causing leaf fall.
- Aphids: These insects damage plants by sucking sap, causing curling and distortion of leaves, and stunting growth.
The simplest method of controlling pesky insects is to maintain healthy plant growth and follow general cultural methods to create a suitable environment for beneficial insects like predators and parasitoids to thrive. If the population of pests becomes too high and causes significant damage, it may be necessary to use insecticides. The use of non-chemical control measures like hand picking, soap and water sprays, and sticky traps can also be an effective approach to control major pest problems.
