Overview
Bidens tenuifolia Labill. is a species of annual plant in the family Asteraceae. It is native to Oceania, specifically Australia and New Zealand, but has been introduced to other parts of the world such as North America, where it is considered an invasive species.
Common Names
Bidens tenuifolia has several common names, including fern-leaved beggar's-tick, devil's-pitchfork, and Spanish needle. The latter is due to the small, needle-like seeds that can stick to clothing and fur.
Uses
Historically, Bidens tenuifolia has been used for medicinal purposes. The leaves, stems, and roots have been used to treat ailments such as rheumatism, toothaches, and infections. The plant has also been used as a natural insecticide and fish poison.
In modern times, the plant is primarily used for its ornamental value. It is often grown in gardens and landscaping for its delicate foliage and bright yellow flowers, which bloom in the summer and fall.
Appearance
Bidens tenuifolia grows up to 1 meter tall and has thin, fern-like leaves that give it a delicate appearance. The leaves are arranged in opposite pairs along the stem and range from 1-7 cm in length. The plant produces small, daisy-like yellow flowers that are 1-2 cm in diameter and have a dark center. The seeds are long and narrow, with small barbs that help them attach to surfaces.
Light Requirements
Bidens tenuifolia Labill. prefers full sun to partial shade for optimal growth. It requires at least 6 hours of direct sunlight per day. Lack of adequate light may cause stunted growth or poor flowering.
Temperature Requirements
Bidens tenuifolia Labill. grows well in warm temperatures and is not tolerant of frost or extreme cold. It requires a minimum temperature of 15°C (59°F) for optimal growth. The ideal temperature range for Bidens tenuifolia Labill. is between 20-30°C (68-86°F).
Soil Requirements
Bidens tenuifolia Labill. can grow in a variety of soil types, but it prefers well-draining soils with a pH of 6.0-7.5. The soil should be fertile and rich in organic matter. Adding compost or organic fertilizer to the soil before planting can help to improve soil fertility and moisture retention. Additionally, it is recommended to keep the soil moist but not waterlogged to prevent root rot.
Cultivation
Bidens tenuifolia, commonly known as the slender beggarticks, is an annual plant that is relatively easy to grow. The plant prefers full sun to partial shade and well-drained soil that is rich in organic matter. It is essential to plant the seeds in an area with good air circulation to prevent disease and pest problems. The crop should also be planted at least three weeks after the last expected frost date in spring.
Watering Needs
The plant requires an equal amount of moisture, but over-watering can cause root rot and other problems like foliar disease and pest infestation. The best way to water Bidens tenuifolia is by deep watering that enables the soil to stay moist, but well-drained. The soil should be watered when the top 1-2 inches are dry. Avoid overhead irrigation as it can cause foliar disease and pest infestation.
Fertilization
Slender beggarticks is relatively less demanding when it comes to fertilizer application than other crops. However, applying a balanced fertilizer at planting can go a long way in ensuring healthy growth and development. The crop should be topdressed with a 5-10-5 or similar fertilizer once every four weeks after germination to encourage flowering and fruiting.
Pruning
Bidens tenuifolia rarely requires pruning unless for maintenance purposes like removing dead, diseased, or damaged stems or branches or to contain growth. The best time to prune is in mid-spring when the plant is still young and actively growing. Cut away any damaged or diseased parts of the plant using sharp and clean pruning shears.
Propagation of Bidens tenuifolia Labill.
Bidens tenuifolia Labill. or the slender-leaf beggarticks is a beautiful plant that is commonly grown in gardens and landscapes. Propagation of the plant can be done through various methods, including seed propagation, cuttings, and division.
Seed propagation
The most common method of propagating Bidens tenuifolia is through seed propagation. The seeds of the plant can be sown directly into the soil during spring or fall. The soil should be well-drained and should have a pH of around 6.0 to 6.5. The seeds should be sown at a depth of around 1/8 inch and should be watered regularly to keep the soil moist until germination.
Cuttings
Bidens tenuifolia can also be propagated through cuttings. Softwood cuttings should be taken during the summer months, and hardwood cuttings should be taken during the winter months. The cuttings should be around 4 to 6 inches long and should be taken from the non-flowering shoots of the plant. The cuttings should be dipped in rooting hormone and planted in small pots filled with a mixture of sand and peat. The cuttings should be kept in a shaded area and should be watered regularly until they develop roots.
Division
Division is another method of propagating Bidens tenuifolia. The plant should be dug up and divided into smaller clumps during the late spring or early fall. The clumps should be replanted in an area with well-draining soil and should be watered regularly until established.
Disease Management
Bidens tenuifolia Labill. plants are prone to several diseases that can impact their growth and productivity. Here are some common diseases that might affect these plants:
- Septoria Leaf Spot: This fungal disease manifests as grayish-brown spots on leaves and stems. It can cause defoliation and reduce plant health. To manage this disease, remove infected plant parts and apply fungicides to prevent further spread.
- Root Rot: This disease is caused by waterlogged soil and attacks the roots of the Bidens tenuifolia. To prevent root rot, avoid over-watering and improve soil drainage. Apply fungicides as needed to prevent the fungus from spreading.
- Mildew: Powdery mildew can affect the leaves and stems of Bidens tenuifolia, leaving them coated in a white, powdery substance. The disease thrives in humid conditions and can be controlled through preventive measures such as planting in well-ventilated areas and applying fungicides.
Pest Management
Besides fungal infections, Bidens tenuifolia is also susceptible to various pests that can cause damage to the plant. Here are some common pests that affect these plants:
- Aphids: These pests feed on the sap of the plant, damaging leaves and stems. They can also transmit viruses that affect the plant's growth. To manage an aphid infestation, use natural predators like ladybugs and lacewings or apply insecticidal soap.
- Spider Mites: These tiny pests can cause damage similar to aphids, but they are harder to see. They can be controlled with insecticidal soap or horticultural oil.
- Caterpillars: Caterpillars can feed on Bidens tenuifolia, causing significant damage to leaves and stems. To control caterpillars, remove them from the plant by hand or apply insecticides.
Regular monitoring and early detection of diseases and pests can help prevent major damage to Bidens tenuifolia. It is always a good idea to consult with a local horticulturist or extension office for further guidance on disease and pest management.
