Silphium laciniatum
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Silphium laciniatum

Compassplant · Polarplant · Pilotweed · Rosinweed

Tier 1 Difficulty: medium Water: moderate Light: full_sun Toxicity: high
Water every
10 days
0
Soil pH
6–7
Hardiness
Zone 3–9
Click count
109
Observations
227

Description

Source: leafsnap

Silphium laciniatum is a species of flowering plant in the family Asteraceae known commonly as compassplant or compass plant. It is native to North America, where it occurs in Ontario in Canada and the eastern and central United States as far west as New Mexico. Other common names include prairie compass plant, pilotweed, polarplant, gum weed, cut-leaf silphium, and turpentine plant. It is a rosinweed of genus Silphium.

Care Guide

💧 Water Every 1-2 weeks

The compass plant, native to North American prairies, is well-known for its exceptional drought tolerance, which is largely due to its deep root system. To align with its natural watering cycle, it should be watered moderately every 1 to 2 weeks. Typically grown outdoors, the compass plant thrives in full sun and benefits from the natural rain patterns that coincide with its growing season.

Suggested frequency: Every 1-2 weeks
FAQ
How should I water my Compassplant?

To keep the Compassplant healthy, it's important to water it correctly. Use filtered water at room temperature or slightly warmer, as tap water may have harmful particles. Avoid using cold water, as it can shock the plant since it naturally grows in warm environments. Instead of watering from above, pour the filtered room temperature water directly onto the soil until it's completely soaked. This helps the plant's roots spread and absorb nutrients.

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

Overwatering is a more common problem for the health of your Compassplant compared to underwatering. When the Compassplant receives too much water, its stems and leaves may wilt and turn yellow. Overwatering for a long time can also lead to diseases like root rot, mold, and mildew, which can be fatal for the plant. Compassplants are fairly tolerant to drought, so underwatering is less likely to occur. However, when it does happen, the leaves of the Compassplant become brittle and brown. It's important to recognize the signs of overwatering early on. Some diseases caused by overwatering, like root rot, may not be fixable if you wait too long. If you notice early signs of overwatering, reduce your watering immediately. You should also assess the soil quality. If it doesn't drain well, replace it with a loose, well-draining potting mix. On the other hand, if you see signs of too little water, simply water more regularly until those signs go away.

How often do I need to water my Compassplant?

If your Compassplant is in a pot, the easiest way to determine if it needs water is to stick your finger into the soil. If the top two to three inches of soil are dry, then it's time to water it. If you have your Compassplant planted outdoors in the ground, you can use a similar method to check the soil. When you find that the top few inches of soil have dried out, it's time to add water. During spring and early fall, using this method usually means watering the plant about once a week. When it gets really hot, you may need to water it twice a week or even more frequently. However, it's worth noting that mature, well-established Compassplants have a strong ability to tolerate drought.

How much water does my Compassplant require?

To water your Compassplant effectively, don't hold back on the amount of water you provide. Make sure the first couple of inches of soil are dry before watering thoroughly. Enough water should be added to completely saturate the soil, allowing excess water to drain through the pot's drainage holes. If you don't notice any excess water draining, it means you haven't watered enough. However, be cautious not to let water accumulate inside the soil, as it can harm the plant. On the other hand, if the water doesn't drain properly, it may indicate poorly draining soil, which is detrimental to the plant's health. For outdoor plants, one inch of rain per week is usually enough.

How do I water my Compassplant during different stages of growth?

The water requirements of the Compassplant can vary depending on its growth stages. When the plant is young or has been recently transplanted, it will need more water than usual. During these stages, the focus is on developing new roots that will support future growth. To ensure optimal root development, slightly more moisture is necessary. As the Compassplant matures, it will require less water. Additionally, during the bloom period, the plant may need increased water as the flowers utilize a significant amount of moisture.

☀️ Light Full sun

Compassplant is a plant that does best in locations that receive sunlight for the entire day. It can also adjust to settings where light is present for only part of the day. Since it comes from regions with plentiful sun, its development may be slowed by persistent shade or insufficient light exposure.

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

Compassplant requires full sun, which means it needs more than 6 hours of sunlight daily, but it can also thrive in partial sun, receiving about 3-6 hours of sunlight. It's crucial to monitor the movement of sunlight through your garden to find spots that offer the ideal balance of light and shade, ensuring optimal growth and health of your plants.

What are the essentials for growing Compassplant?

Compassplant is best suited to environments that offer a full day's light but can adapt to areas with partial day light as well. It originates from regions with abundant sunlight, and its growth may be hindered in constant shade or without sufficient light exposure. For indoor plants, adequate lighting is essential for optimal growth, especially in winter or less sunny spaces. Artificial lights, like LED, can provide necessary light wavelengths, with full sun plants requiring 30-50W/sq ft, partial sun plants 20-30W/sq ft, and full shade plants 10-20W/sq ft. The light source should be placed 12-36 inches above the plant to mimic natural sunlight, and most plants need 8-12 hours of light per day.

What are common symptoms of light deficiency in Compassplant?

When Compassplant is exposed to inadequate lighting, it may exhibit symptoms such as smaller new leaves, leggy or sparse growth, faster leaf drop, slower or halted growth, lighter-colored new leaves, chlorosis, sunscald, leaf curling, wilting, and leaf scorching. These symptoms indicate the plant's struggle with poor light conditions, affecting its growth, leaf production, and overall health.

How can I address insufficient sunlight exposure for Compassplants?

To address insufficient sunlight exposure for Compassplants, gradually move them to sunnier locations, aiming for at least 6 hours of direct sunlight daily, and utilize south-facing windows for indoor plants. For plants that are large or difficult to move, consider artificial lighting, keeping lamps on for at least 8 hours daily. For outdoor plants, ensure a gradual transition to sunnier spots to prevent sunburn. If physical obstructions block sunlight, such as trees, consider pruning to improve light access. For smaller plants, consider transplanting during their dormant period to a location with ample sunlight. Note, however, that parts of the plant already affected may not recover, but new growth should be healthy following these adjustments.

🌡️ Temperature 0–35°C

Compassplant comes from habitats where temperatures commonly range from 32 to 95 °F (0 to 35 ℃). It flourishes in those climates, adapting well as the seasons change. Remember to watch the temperature, particularly during extreme conditions.

Ideal temperature: 0–35°C
FAQ
What is the native environment for Compassplant and how does it adjust to temperature changes?

Compassplant, or Silphium laciniatum, is native to environments that experience a wide range of temperatures, from 32 to 95°F (0 to 35°C). It thrives in these varying climates by effectively adjusting between the seasonal changes. It's important for those cultivating Compassplant to keep an eye on the thermometer, particularly during extreme weather conditions. Despite its strong cold resistance, allowing it to usually forego special frost protection measures in winter, precautions should still be taken if temperatures are forecast to dip below -35°C. This involves covering the plant with insulating materials like soil or straw, and watering it abundantly before the first freeze of autumn to keep the soil moist and reduce the risk of drought and water scarcity during the colder months.

How should Compassplant be cared for in low temperature conditions?

Compassplant demonstrates significant cold tolerance, prospering best in temperatures above 0°C and ideally kept from dropping below -30°C during the winter months. In the case that temperatures fall beneath -35°C, it's possible to observe a lack of visible changes during the winter; however, the repercussions may become apparent in spring with a diminished sprouting or lack thereof. To mitigate this, affected gardeners are advised to remove any parts of the plant that fail to sprout come springtime, maintaining the health and aesthetics of the Compassplant.

What measures should be taken if Compassplant experiences high temperature conditions?

During the summer season, it's critical to ensure that Compassplant remains in temperatures below 35°C to avoid heat-related stress. If the mercury climbs above 38°C, the plant may exhibit symptoms such as leaves lightening in color, curling, becoming susceptible to sunburn, and in severe cases, wilting and drying out entirely. To counteract these effects, sunburned and dried parts of the plant should be trimmed away, and the plant should be moved to a shaded location or protected with a shade cloth during the midday and afternoon sun. Additional watering in the morning and evening will help maintain soil moisture, crucial for the plant's well-being in high temperatures.

💨 Humidity dry (<40%)

This plant prefers dry conditions, so don't mist it. However, watering it less often can also thrive in higher humidity.

Humidity: dry (<40%)
🪴 Soil 6-7
Soil pH: 6-7
🌱 Fertilizer

The best time to fertilize a Compassplant is in early spring, as it comes out of dormancy and starts active growth. Fertilizing supplies essential nutrients needed for healthy development. While Compassplant has relatively low fertilizer requirements, applying fertilizer annually can improve its survival and encourage better, longer-lasting flowers.

FAQ
Why should I put fertilizer on my Compassplant?

To keep your Compassplant healthy and ensure its leaves look great, fertilization is key. The leaves are the main structure of the Compassplant, so proper fertilization is vital for maintaining consistent color and a healthy texture. Additionally, fertilization benefits the plant's root system, helping it generate new roots and maintain existing ones. This not only promotes immediate plant health but also improves its ability to absorb soil nutrients in the long run.

When should I fertilize my Compassplant for the best results?

If you choose to grow your Compassplant outdoors every year, you'll see new growth in early spring. This is the cue to start fertilizing. Usually, a single application of fertilizer will be enough. But if you want your Compassplant to really thrive, you can fertilize it multiple times throughout the spring and early summer. In this case, you can feed it about once every month to a month and a half.

When should I not put fertilizer on my Compassplant?

During late fall and winter, your Compassplant goes into a dormant phase and stops growing. During this time, it is recommended to refrain from fertilizing it. In spring and summer, if you choose to fertilize, gradually decrease the frequency as summer approaches since the plant's growth rate slows down. It is generally not advisable to fertilize your Compassplant when the weather is unusually hot or the soil is excessively dry, as this can cause stress and premature death.

What kind of fertilizer should I use for my Compassplant?

Choosing the best fertilizer for a Compassplant is easy. These plants do well with a general-purpose garden fertilizer that has equal amounts of nitrogen, phosphorus, and potassium, like a 10-10-10 ratio. Just avoid fertilizers high in nitrogen if unsure. Granular, slow-release fertilizers are most recommended. Applying them to the soil is simple. Using organic soil amendments like compost can also be beneficial for feeding your Compassplant.

How can I give my Compassplant the nutrients it needs?

To help your Compassplant thrive, follow these steps. Wait until early spring when you see the first leaves breaking through the surface of the soil. Once this happens, apply a balanced slow-release fertilizer to the soil around the base of the plant. You can repeat this process later in the season if desired. When reapplying fertilizer, make sure to apply it to the soil at the base of the plant instead of directly on the plant itself. Sometimes, you may need to gently move the leaves to reach the soil above the roots. It's also a good idea to water your Compassplant before and after fertilizing for optimal growth.

🪴 Pot & Repot

For the compass plant to thrive in pots, excellent drainage is crucial. This ensures proper aeration and helps prevent root rot. Good drainage is vital for healthy growth and effective water management.

✂️ Pruning

The compass plant benefits greatly from regular pruning, especially in the spring when it is actively growing. By removing damaged stems, you encourage new growth. Pruning before the plant flowers can prevent it from becoming leggy. Additionally, proper pruning enhances airflow and sunlight exposure, which reduces the risk of disease and helps the plant develop a stronger structure.

🌿 Propagating
🐛 Diseases & pets
☠️ Toxicity

Characteristics

Plant Type
Herb
Life Cycle
Perennial
Genus
Silphium
Family
Asteraceae
Hardiness Zone
3-9
Mature Height
0.91 m to 1.83 m
Mature Spread
91 cm
Leaf Color
Green
Leaf Type
Deciduous
Flower Color
Yellow
Flower Size
2.54 cm to 15.24 cm
Bloom Time
Early summer, Mid summer
Planting Time
Spring, Autumn
Harvest Time
Mid summer
Native Area
Prairies of North America

Tags (29)

Common Names (4)

en Compassplant
en Polarplant
en Pilotweed
en Rosinweed