Bidens pilosa
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Bidens pilosa

Spanish-needles · Blackjack · Beggar-ticks · Cobblers'-pegs · Hairy beggar-ticks

Tier 1 Difficulty: medium Water: moderate Light: full_sun Toxicity: low
Water every
3 days
Temperature
10–37 °C
Soil pH
6–7
Hardiness
Zone 6–12
Click count
1,394
Observations
2,499

Description

Source: leafsnap

Bidens pilosa, commonly known as Spanish needle or black-jack, is a flowering plant belonging to the Asteraceae family. Although it is native to South America, it has spread globally and is now found in many tropical and subtropical regions. The plant can grow up to 1 meter tall and features slender stems and serrated green leaves. Its small flowers, which are yellow or orange, bloom from summer through fall. For centuries, indigenous people worldwide have used Bidens pilosa for medicinal purposes, believing it to have anti-inflammatory properties. It is employed as a natural remedy for various ailments, including fever, coughs, colds, diarrhea, and dysentery, among others. Additionally, the plant serves as a food source for some animals; birds feed on its seeds, and certain insects nectar from its flowers. However, despite its medicinal benefits, Bidens pilosa can also be considered an invasive weed. Its seeds easily attach to clothing or animal fur, facilitating its rapid spread to new areas where it can outcompete native plants. In summary, Bidens pilosa is an intriguing plant with notable medicinal advantages but also has the potential to negatively impact ecosystems where it becomes invasive.

💡 Although commonly regarded as a weed, hairy beggarticks, or Bidens pilosa, has been traditionally used worldwide for both food and medicinal purposes. During the Vietnam War, soldiers incorporated it into their diet, earning it the nickname "soldier vegetable." In regions like China and Southern Africa, it is also valued for its medicinal properties.

🌳 Black-jack, a versatile entity, has moved well beyond its medicinal reputation, supplying natural yellow dyes from extracts rich in flavonoids. It also plays an unexpected ecological role, indicating elevated levels of certain toxic metals, such as nickel, in soil. This feature highlights its suitability for phytoremediation, the use of plants to clean up polluted environments.

🎭 Caution against jealousy and covetousness

Care Guide

💧 Water Every 3 days

Hairy beggarticks originates from tropical regions and prefers consistently moist environments. It thrives with weekly watering but can tolerate brief periods of dryness. When grown outdoors, it benefits from rain during the growing season, which supports its growth and health.

Suggested frequency: Every 3 days
FAQ
How should I water my Hairy beggarticks for the best results?

To water Hairy beggarticks, you have a few options. You can use a garden hose with a spray nozzle, a watering can, or any other common watering tool. Hairy beggarticks isn't too picky about water sources and can handle rainwater, tap water, or even filtered water. However, it's best to avoid watering this plant from above, as it can harm leaves, flowers, and potentially cause disease. Instead, a drip irrigation system is often the most effective way to water Hairy beggarticks. These systems evenly distribute water directly to the soil. When it comes to watering container-grown Hairy beggarticks, you'll follow a similar approach but using a cup, watering can, or tap to apply water directly to the soil.

What should I do if I give too much or too little water to my Hairy beggarticks?

The solution to underwatering Hairy beggarticks is simple: water it more regularly when you notice it lacks moisture. However, overwatering can be a more serious issue. If you don't catch it early, your Hairy beggarticks can become susceptible to diseases that could lead to its decline and death. To prevent this, choose a suitable location for your plant with ample sunlight to dry out the soil and good drainage to avoid water pooling and waterlogged soil. If you have an overwatered Hairy beggarticks in a pot, consider transferring it to a new pot with better drainage and loose soil.

How frequently should I water my Hairy beggarticks?

Hairy beggarticks requires regular watering throughout the growing season. Starting in spring, water this plant once a week. As the season progresses and temperatures rise, increase watering to two or three times a week. However, over-watering can harm the plant. Ensuring the soil remains moist but not wet is important, regardless of watering frequency. If growing Hairy beggarticks in a pot, watering needs differ. Generally, water container-grown plants more often, as pot soil can dry out quicker than ground soil. In most cases, water potted Hairy beggarticks a few times a week, compared to once a week for in-ground plants.

How much water does my Hairy beggarticks plant need?

Determining how much water to give your Hairy beggarticks can be done in a few different ways. One approach is to feel the soil to check for moisture. If the top six inches of soil feel dry, it's time to water. Another option is to use a set measurement, typically around two gallons per week. However, be mindful of your plant's specific needs to avoid overwatering. When growing in a container, you'll need a different method. Make sure to moisten all the dry layers of soil by testing with your finger or watering until you see some excess water draining out of the pot.

How do I know if I am giving enough water to my Hairy beggarticks?

Avoiding overwatering your Hairy beggarticks can be tricky. These plants have deep roots that need weekly watering, but they are also prone to root rot. Overwatering can lead to browning and other problems. Underwatering is less of a concern as these plants can survive without extra watering for a while, but they may wilt and have dry leaves if left without water for too long.

☀️ Light Full sun

Black-jack does best with ample light yet tolerates a moderate amount of shade. Native to sunny environments, it has adapted to prosper under bright sunlight for optimal growth. Both insufficient and excessive sunlight can harm its health and interfere with its normal development.

Ideal: Full sun
FAQ
What are the sunlight requirements for hairy beggarticks?

Hairy beggarticks requires plenty of light to flourish, thriving best in full sun conditions of over 6 hours of sunlight a day but can also handle partial sun, which amounts to about 3-6 hours of sunlight daily. It's essential to monitor the movement of sunlight through your garden to ensure that your plants receive the ideal balance of light and shade, which is crucial for their growth and health.

How does artificial lighting benefit indoor plants like hairy beggarticks?

When natural sunlight is not sufficient, especially during winter or in less sunny areas, artificial lighting becomes crucial for indoor plants, including hairy beggarticks. Artificial lights, such as LED, can be tailored to provide specific wavelengths needed for the plant's growth, promoting faster, healthier development. For full sun plants, 30-50W per square foot is recommended, partial sun plants require 20-30W per square foot, and full shade plants need 10-20W per square foot. The artificial light source should be placed 12-36 inches above the plant and turned on for 8-12 hours per day to mimic natural sunlight duration.

What symptoms indicate insufficient sunlight for hairy beggarticks?

Insufficient sunlight can lead to several symptoms in hairy beggarticks, including smaller new leaves, leggy or sparse growth, faster leaf drop, slower or ceased growth, lighter-colored new leaves indicating a lack of chlorophyll, and chlorosis where leaves turn yellow. Sunscald, leaf curling, wilting due to water loss, and leaf scorching from excessive sunlight are also signs that the sunlight conditions are not optimal for the plant's health.

What solutions can address hairy beggarticks' insufficient sunlight exposure?

To remedy insufficient sunlight for hairy beggarticks, gradually move the plant to a sunnier location, ensuring it receives at least 6 hours of direct sunlight daily. Utilize south-facing windows and keep curtains open during daylight. For large or immobile plants, consider artificial lighting for at least 8 hours per day. Outdoors, adapt plants to sunlight gradually to prevent sunburn. Reducing obstructions, such as pruning trees, can help, and transplanting smaller plants to more sunlight-friendly locations may be necessary. Note that parts of the plant already affected by low light may not recover, but new growth should be healthy once light conditions improve.

🌡️ Temperature 10–37.8°C

Black-jack is naturally adapted to tolerate temperatures between 68 and 100 °F (20 and 38 ℃) because of its native growing environment. In cooler seasons, modify temperatures as needed to maintain healthy growth.

Ideal temperature: 10–37.8°C
FAQ
What temperature range can Hairy beggarticks handle, and how should it be adjusted in cooler seasons?

Hairy beggarticks thrives in a range of 68 to 100 °F (20 to 38 °C), attributed to its origin in varied native growth environments. In cooler seasons, it is essential to adjust temperatures accordingly to promote healthy growth. The plant possesses robust cold resistance, reducing the need for special frost protection measures in winter. Nevertheless, should winter temperatures be anticipated to fall below -25°C, it becomes crucial to implement cold protection strategies, such as covering the plant with soil or straw. It is also advisable to water the plant plentifully before the first freeze of autumn to maintain soil moisture in a frozen state, averting drought and water scarcity for the plant during winter and the onset of spring.

How does Hairy beggarticks react to low temperatures, and what are the solutions if it fails to sprout in spring?

Hairy beggarticks displays considerable cold tolerance, flourishing optimally when temperatures remain above 20°C. It is advised to keep it above 0°C during winter. If temperatures plummet beneath -25°C, while no visible alterations might occur during winter, a reduction in sprouting or complete absence of sprouting can be observed in spring. The solution to this challenge involves removing any parts of the plant that have not sprouted in the spring.

What are the effects of high temperatures on Hairy beggarticks, and how can they be mitigated?

During the summer, it is critical to ensure that the temperature around Hairy beggarticks does not exceed 38°C. Exposure to temperatures above 43°C can result in the plant's leaves becoming lighter, curling, being prone to sunburn, and in severe instances, the plant may wilt and become dry. To mitigate these effects, it is recommended to trim away the sunburned and dried parts of the plant. Relocating the plant to a shaded area during the midday and afternoon sun or employing a shade cloth can be effective solutions. Additionally, watering the plant in the morning and evening helps maintain soil moisture, further aiding in the plant's recovery and health under high temperatures.

💨 Humidity normal (40-60%)

This plant will thrive in moderate humidity, which is probably the level in your home. However, misting it a few times a week can be very beneficial. Make sure the room has good ventilation.

Humidity: normal (40-60%)
🪴 Soil 6-7
Soil pH: 6-7
🌱 Fertilizer

Black-jack responds well to regular, light applications of fertilizer to encourage healthy leaf development. Fertilize Black-jack about once a month during the summer. Nitrogen is important for foliage, and providing nitrogen-rich sources helps Black-jack thrive.

🪴 Pot & Repot
✂️ Pruning
🌿 Propagating
🐛 Diseases & pets
☠️ Toxicity

Characteristics

Plant Type
Herb
Life Cycle
Annual, Perennial
Genus
Bidens
Family
Asteraceae
Hardiness Zone
6-12
Mature Height
0.1 m to 1.83 m
Mature Spread
20 cm to 91 cm
Leaf Color
Green
Leaf Type
Deciduous
Flower Color
White, Yellow
Flower Size
0.51 cm to 1.52 cm
Bloom Time
All year round
Planting Time
Spring
Harvest Time
All year round
Native Area
Sri Lanka, Saudi Arabia, Egypt, Belize, Honduras, Mexico, Peru, Pakistan, Laos, Trinidad and Tobago, Panama, Jamaica, Lebanon, Uruguay, Colombia, Cuba, Haiti, Cameroon, Bolivia, Venezuela, Guyana, El Salvador, Nicaragua, Bhutan, South Korea, Suriname, Costa Rica

Tags (30)

Common Names (30)

en Spanish-needles
en Blackjack
en Beggar-ticks
en Cobblers'-pegs
en Hairy beggar-ticks
en Hairy bidens
en Farmer's Friends
en Soldier's vegetables
en Z'Herbe Zuedruite
en Hairy Beggarticks
en Rebbhâ sangkap
en Hairy Beggar's ticks
en Railway beggarticks
en Beggar's ticks
en Cobbler's pegs
en Common beggarticks
en Fisi`uli
en Romerillo
en Beggar's-tick
en White beggar's ticks
en Common blackjack
en Railway daisy
en Beggartick
en Shepherd's needle
en Spanish needle
en Bidens
en Bur-marigold
en Cuckold
en Kofe tonga
en Sticktight