Parentucellia latifolia — a medium houseplant, prefers full sun light
SPECIMEN · FROM THE LIBRARY
Parentucellia latifolia

Parentucellia Latifolia

Updated · 376 observations
ON THIS PLANT

Parentucellia latifolia is a species of flowering plant in the family Orobanchaceae known by several common names, including red bartsia, red tarweed, and broadleaf glandweed. It is native to Europe, but it can be found on other continents, including Australia, as an introduced species. This is an erect annual herb producing a stiff, slender stem coated in hairs and sticky glands. It reaches a maximum height near 30 centimeters. The hairy leaves are divided into triangular or lance-shaped lobes. The inflorescence is a raceme of flowers at the end of the stem. The flower is tubular, the calyx of sepals extending about halfway along the centimeter-long corolla. The corolla is magenta in color, sometimes with white areas, and bearing two raised yellow appendages in the lobed throat.

A note from PlantMom

Broadleaf glandweed is fairly disease-resistant and usually does not suffer from many illnesses. However, it can be affected by pests and diseases found in its environment. These infections are generally mild. Concerning care, this plant requires moderate maintenance. Regular pruning is needed to keep a tidy appearance and support healthy growth. Fertilizing can also encourage flowering. Broadleaf glandweed is well suited for anyone with an outdoor area, such as a garden or patio, and does not demand extensive care experience. It may need more attention when grown indoors.

— PlantMom
CARE GUIDE

How to keep Parentucellia Latifolia.

Light

Broadleaf glandweed comes from bright, open habitats and does best in full sun. It tolerates partial sun but favors direct sunlight for optimal growth. This plant, which can be annual or biennial, is known for its sun-loving nature.

Water

Broadleaf glandweed thrives in moderate climates and requires consistent moisture to grow well. To keep it healthy, it's essential to water it regularly, ideally once a week. During its active growing season, maintaining moist soil is crucial for promoting growth and optimizing water absorption. This practice mirrors the plant's natural habitat conditions and ensures its vitality.

Temperature

Broadleaf glandweed can tolerate a wide range of temperatures, although its distribution may still be restricted by different combinations of moisture and heat. It grows best in warm summer climates with sufficient rainfall or watering. Extended periods of cloudy, rainy weather or prolonged high temperatures can raise the chance of Broadleaf glandweed dying. In winter, protecting it from cold can increase its survival rate.

Fertilizer

Broadleaf glandweed responds well to regular, dilute fertilizer applications to encourage healthy foliage. Fertilize Broadleaf glandweed roughly once a month during the summer. Nitrogen is important for the leaves, and supplying nitrogen-rich sources helps Broadleaf glandweed thrive.

Pruning

Broadleaf glandweed has wide leaves and glandular hairs, and it benefits from light pruning between early and late spring. To improve its shape and airflow while reducing disease risk, trim any dead stems. Use sharp, sanitized tools to make clean cuts just above the nodes, which encourages optimal healing and regrowth.

CHARACTERISTICS

Botanical profile.

Plant Type
Herb
Life Cycle
Annual
Genus
Parentucellia
Family
Orobanchaceae
Hardiness Zone
7-10
Mature Height
30 cm
Mature Spread
5 cm to 15 cm
Leaf Color
Green
Leaf Type
Semi-evergreen
Flower Color
Yellow, Pink
Flower Size
1.02 cm to 1.52 cm
Bloom Time
Mid spring, Late spring
Planting Time
Spring
Harvest Time
Early summer, Mid summer
ALSO KNOWN AS

Other names.

en Broadleaf Glandweed en Red tarweed en Common bartsia en Broad-leaved glandweed en Southern red bartsia en Broad-leaved Eyebright
FREQUENTLY ASKED

Reader questions.

How should I water my Broadleaf glandweed plant to keep it healthy?

To water Broadleaf glandweed, you can use a garden hose with a spray nozzle, a watering can, or any other common watering tool. They are not picky about the water source and can survive with rainwater, tap water, or filtered water. Avoid watering from above to prevent leaf and flower damage or disease. Setting up a drip irrigation system is often the best method for watering this plant as it applies water evenly and directly to the soil. If you are watering a container-grown Broadleaf glandweed, use a cup, watering can, or tap to apply water directly to the soil.

What are the sunlight requirements for Broadleaf glandweed?

Broadleaf glandweed thrives in environments with strong sunlight exposure. It requires full sun, defined as more than 6 hours of direct sunlight daily, to flourish. The plant can tolerate partial sun, approximately 3-6 hours of sunlight, but for optimal growth, full sun is preferred. It's important to observe the movement of sunlight through your garden to ensure your Broadleaf glandweed gets the perfect balance of light and shade.

What should I do if I give my Broadleaf glandweed too much or too little water?

The solution for underwatering Broadleaf glandweed is straightforward. Simply water it more regularly when you notice that it lacks moisture. Overwatering, however, can be a serious issue if not addressed early. When Broadleaf glandweed is overwatered, it can become susceptible to diseases that can lead to its decline and death. To prevent this, choose a suitable location for growth – one with ample sunlight to dry the soil and good drainage to prevent water from pooling and causing waterlogged soil. If you have overwatered Broadleaf glandweed in a pot, consider transferring it to a new pot with better drainage. The previous container may not have had enough drainage holes or had soil that allowed for proper drainage. When repotting the overwatered plant, use loose soil and an efficient draining pot.

How does artificial lighting benefit indoor Broadleaf glandweed plants, and what are some tips for using it?

Indoor Broadleaf glandweed plants benefit significantly from artificial lighting, especially when natural sunlight is insufficient. Artificial lights, such as LEDs, can be customized to the plant's needs, providing specific wavelengths for healthier growth. For full sun plants, 30-50W/sq ft is recommendable; partial sun plants need 20-30W/sq ft, and full shade plants should have 10-20W/sq ft. 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 daylight hours, promoting optimal growth.

How often do I need to water my Broadleaf glandweed?

Broadleaf glandweed requires regular watering throughout the growing season. In the spring, watering once a week is sufficient. However, as the season progresses and becomes hotter, you may need to water two to three times per week. It's important not to go overboard with watering as it can harm the plant. Keep the soil relatively moist, but avoid making it wet. When it comes to potted Broadleaf glandweed, you'll need to water more frequently compared to plants in the ground. Since pot soil can heat up and dry out faster, aim to water container-grown Broadleaf glandweed a few times per week, rather than just once per week for plants in the ground.

What are the symptoms of light deficiency in Broadleaf glandweed?

Broadleaf glandweed shows several symptoms when experiencing light deficiency, including the growth of smaller new leaves, leggy or sparse growth, faster leaf drop, slower or halted growth, and the appearance of lighter-colored or yellow leaves due to chlorosis. Other symptoms of too much sunlight include sunscald, leaf curling, wilting, and leaf scorching, indicating the plant is receiving more light than it can handle.

How much water does my Broadleaf glandweed require?

Determining how much water to give your Broadleaf glandweed can be approached in a few different ways. Some gardeners prefer to assess the soil's moisture level by feeling it. According to this method, you should water until the top six inches of soil feel moist. Alternatively, you can use a specific measurement as a guide. Generally, about two gallons of water per week should suffice for your Broadleaf glandweed, depending on the temperature and how quickly the soil dries. However, strictly adhering to these guidelines may cause overwatering if your plant requires less water for any reason. When growing Broadleaf glandweed in a container, a different approach is necessary. In this case, you should water enough to moisten all the dry soil layers. You can check for moisture by inserting your finger into the soil or by watering until you observe a slight trickle of excess water draining from the pot's drainage holes.

What solutions can help Broadleaf glandweed receiving insufficient sunlight?

For indoor plants, gradually increase sunlight exposure or use artificial lighting to ensure at least 6 hours of direct sunlight daily. A south-facing window is ideal. For outdoor plants, slowly move them to sunnier spots each week to avoid shock. If the plant's location is obstructed, consider pruning nearby trees or transplanting the plant to a sunnier spot. Remember that while some parts of the plant may not recover from light deficiency, new growth will be healthy with improved light conditions.

How do I know if I'm giving enough water to my Broadleaf glandweed?

Avoiding overwatering your Broadleaf glandweed can be challenging because these plants have deep roots that need weekly soil moistening. However, they are highly susceptible to root rot and can develop browning due to excessive watering. Underwatering is less of a concern as these plants can survive without supplemental watering for a period of time. However, if you go too long without watering, the plant may wilt and exhibit dry leaves.

How do I water my Broadleaf glandweed in different seasons?

As the season progresses, your Broadleaf glandweed's water needs will increase. In the spring, watering once per week should suffice. However, as the summer heat sets in, you may need to water your Broadleaf glandweed more frequently, about three times per week. This is especially important if your Broadleaf glandweed is in a container, as container soil tends to dry out faster in warm weather. In the autumn, when your Broadleaf glandweed is still blooming, it may require less water due to the lower temperatures and weaker sunlight compared to the summer.

How do I water my Broadleaf glandweed as it grows?

Throughout the year, Broadleaf glandweed goes through various growth stages, each with different water requirements. Starting as a seed, it needs more water during germination. During this time, water often to keep the soil consistently moist. Once it grows above the soil, it needs slightly less water. Once it reaches maturity, water it once a week. During flower development, consider giving slightly more water to help the process.

What's the difference between watering Broadleaf glandweed inside and outside?

Most Broadleaf glandweed prefer outdoor growing for a few reasons. Firstly, they tend to grow quite tall. Secondly, they require more sunlight than most indoor locations can offer. If you are able to provide a suitable indoor growing spot, keep in mind that you may need to water your Broadleaf glandweed more frequently compared to outdoor growing. This is because indoor environments are generally drier, thanks to HVAC units, and soil in containers can dry out quickly too.

PLATES
Parentucellia latifolia leaf
PLATE 01 · leaf
Parentucellia latifolia leaf
PLATE 02 · leaf
Parentucellia latifolia flower
PLATE 03 · flower
Parentucellia latifolia flower
PLATE 04 · flower
Parentucellia latifolia fruit
PLATE 05 · fruit
Parentucellia latifolia fruit
PLATE 06 · fruit
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