Lithospermum officinale
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Lithospermum officinale

Common gromwell · Pearl gromwell · Gromwell · European stoneseed · European Gromwell

Tier 1 Difficulty: medium Water: low Light: full_sun
Temperature
5–35 °C
Soil pH
6–7
Hardiness
Zone 5–9
Click count
480
Observations
1,185

Description

Source: leafsnap

Lithospermum officinale, or common gromwell or European stoneseed, is a flowering plant species in the family Boraginaceae, native to Eurasia. It is the host plant for caterpillars of the monophagous moth Ethmia dodecea.

Care Guide

💧 Water

Gromwell grows best in well-drained soils and needs moderate moisture to thrive. For optimal growth, it should be watered weekly to replicate its natural environment. When grown indoors, gromwell requires consistent moisture, but it's important to avoid waterlogging. This makes it perfect for container cultivation, as it helps prevent root rot.

FAQ
How should I water my Gromwell plant?

To properly water the Gromwell, it's best to use filtered water that is at room temperature. Tap water may contain harmful particles, so filtered water is safer. The Gromwell prefers warm environments, so avoid using cold water as it can shock the plant. Additionally, overhead watering should be avoided to prevent issues with the foliage. Instead, gently pour the filtered room temperature water onto the soil until it is completely soaked. This helps moisten the roots and allows them to spread and absorb nutrients from the soil effectively.

How frequently should I pour water on my Gromwell?

If your Gromwell plant is in a pot, the most precise way to determine if it needs water is by checking the moisture level in the soil. Simply stick your finger into the soil and if the top two to three inches are dry, it's time to water. If you have your Gromwell planted outdoors in the ground, you can use a similar method to test the soil. When the top few inches of soil are dry, it's a sign that watering is needed. Depending on the season, watering once every week is typically sufficient during spring and early fall. However, during extremely hot weather, you may need to water twice or more per week. It's worth noting that mature and well-established Gromwell plants have the ability to withstand drought.

How much water does my Gromwell plant need?

When it's time to water your Gromwell, don't be shy with the amount of water you give. Make sure the first two to three inches of soil are dry before watering. It's best to give the plant a good, deep watering so that the soil is completely soaked. You should add enough water for it to flow out of the drainage holes at the bottom of the pot. If you don't see excess water draining, you may not have given enough water. However, be careful not to let water accumulate inside the soil, as this can be harmful to the plant. Conversely, if water isn't draining through the pot, it may indicate poorly draining soil, which is bad for the plant's health. If the Gromwell is outside, one inch of rain per week is enough.

How should I water my Gromwell plant when it is growing at different stages?

The water requirements of the Gromwell can vary depending on its growth stages. In the early years or after transplanting, it needs more water to support root development for future growth. As it matures, it requires less water. Additionally, during the bloom period, the Gromwell may need increased water due to the moisture needed for flower development.

What do I need to do if I give my Gromwell plant too much water or too little water?

Overwatering and underwatering can both harm your Gromwell, but overwatering is more commonly problematic. When your Gromwell gets too much water, its stems and leaves may wilt and turn yellow. Prolonged overwatering can also lead to diseases like root rot, mold, and mildew, which can kill your plant. Gromwells are fairly tolerant to drought, so underwatering is less common. However, it is still possible and can cause the leaves to become brittle and brown. It is important to recognize the signs of overwatering early when taking care of your Gromwell. Some diseases caused by overwatering, such as root rot, may become irreversible if not addressed promptly. If you spot early signs of overwatering, reduce your watering immediately. Also, check the soil quality where your Gromwell is growing. If the soil drains poorly, replace it with a loose, well-draining potting mix. On the other hand, if your Gromwell shows signs of not getting enough water, simply water more regularly until the signs improve.

☀️ Light Full sun

The gromwell thrives in strong sunlight, though it also tolerates partial shade. Growing in sunny areas promotes its best development in well-lit conditions. A lack of light or excessive exposure can impede its vigorous growth, leading to reduced vigor or potential sunscorch.

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

Gromwell requires full sun exposure of above 6 hours of sunlight daily for optimal growth but can also adapt to partial sun conditions with about 3-6 hours of sunlight. It's essential to observe how sunlight moves through your garden to find the perfect balance of light and shade for your plants. This ensures they thrive in their environment.

How does insufficient or excessive sunlight affect Gromwell?

Gromwell flourishes best under robust solar illumination and can adapt well to partial luminosity. Optimal growth is seen in regions of abundant sunshine, where the plant can enjoy well-lit environments. Both the scarcity and overabundance of light can negatively impact the plant, leading to suppressed vitality, possible sunscorch, or hindered vigorous development.

Can artificial lighting be used for Gromwell, and how?

Yes, artificial lighting can support Gromwell's growth, especially indoor, when natural sunlight is insufficient. This is relevant during winter or in less sunny spaces. LED lights are preferred for their capability to provide specific wavelengths needed for the plant. Full sun plants require 30-50W/sq ft, partial sun plants 20-30W/sq ft, and full shade plants 10-20W/sq ft of artificial light. The light source should be placed 12-36 inches above the plant to mimic natural sunlight and left on for 8-12 hours per day to ensure optimal growth.

What are the symptoms of light deficiency in Gromwell?

Symptoms of light deficiency in Gromwell include small, new leaves, leggy or sparse growth, faster leaf drop, slower or no new growth, lighter-colored new leaves, chlorosis, sunscald, leaf curling, wilting, and leaf scorching. These symptoms indicate that the plant is not receiving adequate sunlight, leading to a variety of health issues.

What solutions are there for Gromwell experiencing light deficiency?

For indoor Gromwell plants experiencing light deficiency, gradually moving them to sunnier locations to receive at least 6 hours of direct sunlight daily is advised. Artificial lighting, such as desk lamps or professional grow lights, can also provide additional light. Outdoors, gradually adapt plants to sunnier spots to prevent sunburn. Reducing obstructions like overhanging branches can help, as can transplanting smaller plants to sunnier locations. Note that parts of the plant damaged by insufficient light may not recover, but new growth will be healthy with improved light conditions.

🌡️ Temperature 5–35°C

Gromwell is a plant that grows best in locations with temperatures between 41 and 95 °F (5 and 35 ℃). Native to temperate regions, it needs cooler winter temperatures to trigger dormancy and warmer temperatures in spring and summer to encourage vigorous growth.

Ideal temperature: 5–35°C
FAQ
What are the ideal temperature conditions for growing Gromwell?

Gromwell, botanically known as Lithospermum officinale, is a plant that grows best in temperate regions, requiring temperatures between 41 to 95°F (5 to 35°C) to thrive. It possesses strong cold resistance, making special frost protection measures unnecessary in most cases. However, during winter, it's crucial to ensure that the plant is protected if temperatures are expected to drop below -25°C. One way to protect Gromwell during extreme cold is by covering it with soil or straw. Additionally, watering the plant abundantly before the first freeze of autumn helps maintain soil moisture, preventing drought and ensuring the plant remains hydrated during winter and early spring.

How does Gromwell react to low temperatures, and what are the recommended solutions?

Gromwell is cold-tolerant and generally thrives best when the temperature remains above 5°C. During the winter months, it's important to ensure that temperatures stay above -20°C. If temperatures fall below -25°C, the plant may not exhibit immediate visible changes, but there could be a noticeable decrease in sprouting, or in some cases, no sprouting at all come spring. To manage this, any parts of the plant that have failed to sprout by spring should be removed to encourage new growth and preserve the plant's health.

How should Gromwell be cared for during high temperatures?

Gromwell should ideally be kept in conditions below 35°C during the summer. If temperatures soar above 38°C, the plant may show signs of stress, such as leaves becoming lighter, curling at the edges, becoming prone to sunburn, or in severe cases, the plant may wilt and dry out entirely. To mitigate these effects, sunburned and dried-up parts of the plant should be trimmed away promptly. Moving the plant to a shaded location, especially away from the harsh midday and afternoon sun, or utilizing a shade cloth can provide necessary protection. Additionally, watering the plant during the cooler morning and evening hours helps keep the soil at an optimal moisture level.

💨 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

One application of fertilizer in spring is typically adequate for Gromwell, although several feedings can maximize its growth. Fertilize every month to every month and a half. Feeding improves the leaves' appearance and function, helping maintain even color and a healthy texture. It also promotes root development and nutrient uptake, supporting the plant's long-term health.

FAQ
Why do I have to put fertilizer on my Gromwell plant?

The main structure of the Gromwell is comprised of its leaves. Fertilization is crucial for maintaining the appearance and function of these leaves. Proper fertilization ensures consistent color and a healthy texture in the leaves. Additionally, fertilization helps the Gromwell develop new roots and maintain existing ones beneath the soil's surface. This not only promotes current plant health but also improves the plant's ability to absorb nutrients from the soil in the future.

When should I fertilize my Gromwell plant for maximum growth?

If you grow your Gromwell outdoors, it will send out new growth in early spring, indicating that it's time to fertilize. Typically, one application of fertilizer is sufficient for a Gromwell to thrive in the spring. However, if you want to maximize its growth, you can fertilize it multiple times during the spring and early summer. In this case, feeding the Gromwell every month to a month and a half is recommended.

When is not a good time to fertilize my Gromwell?

During late fall and winter, your Gromwell enters a dormant phase, meaning it stops growing. So, you shouldn't fertilize it during this time. When spring and summer come, you can fertilize your Gromwell multiple times, but as summer gets closer, you should reduce the amount of fertilizer you use because the growth rate of your Gromwell also slows down. Remember, it's never a good idea to fertilize your Gromwell when the weather is unusually hot or the soil is extremely dry. Fertilizing in those conditions can stress your Gromwell and cause it to die sooner.

What kind of fertilizer should I use for my Gromwell?

Choosing the best fertilizer for a Gromwell is straightforward. Opt for a general-purpose garden fertilizer with equal amounts of nitrogen, phosphorus, and potassium, like a 10-10-10 ratio. Avoid high-nitrogen fertilizers if unsure. Granular fertilizers are ideal, especially slow-release ones that are easy to apply to the soil. An organic soil amendment such as compost can also benefit your Gromwell when being fed.

How do I make my Gromwell plant grow better?

To ensure proper growth of your Gromwell, wait until its first leaves emerge in early spring. Once you see these leaves, apply a granular slow-release fertilizer with a balanced formula to the soil around the base of your Gromwell. You can repeat this process later in the season if desired. When reapplying the fertilizer, make sure to apply it to the soil at the base of the plant, not directly onto the plant itself. You may need to move some leaves aside to access the soil above the roots. It's also beneficial to water your Gromwell before and after fertilizing.

🪴 Pot & Repot
✂️ Pruning

Gromwell is known for its hard, white fruits and lance-shaped leaves. Pruning should be done from early to late spring and involves removing dead wood and thinning branches to improve air circulation and light penetration. It's essential to sterilize your tools to prevent disease, which promotes healthier growth and enhances flowering.

🌿 Propagating
🐛 Diseases & pets
☠️ Toxicity

Characteristics

Plant Type
Herb
Life Cycle
Perennial
Genus
Lithospermum
Family
Boraginaceae
Hardiness Zone
5-9
Mature Height
76 cm
Mature Spread
20 cm to 40 cm
Leaf Color
Green
Leaf Type
Deciduous
Flower Color
White
Flower Size
0.76 cm
Bloom Time
Late spring, Early summer, Mid summer
Planting Time
Spring, Summer
Harvest Time
Late summer, Early fall, Mid fall
Native Area
Turkey, Sweden, India, Austria, Slovakia, Montenegro, Pakistan, Slovenia, Croatia, Belarus, Uzbekistan, Russia, Iraq, Germany, Estonia, Romania, Latvia, Belgium, Portugal, Nepal, Netherlands, France, Tajikistan, Czech Republic, Bulgaria, Armenia, Poland, Greece, Ukraine, Serbia, Lebanon, Lithuania, Norway, China, Afghanistan, Kyrgyzstan, Kazakhstan, Italy, Spain, Switzerland, Denmark, Finland, Bhutan, Iran, Albania, Ireland, United Kingdom, Hungary, Azerbaijan, Turkmenistan

Tags (4)

Common Names (5)

en Common gromwell
en Pearl gromwell
en Gromwell
en European stoneseed
en European Gromwell