Key Lime vs Pickerel Weed Plant Comparison

Compare these two plants side by side — care needs, key differences, and which is right for your home.

Key Lime

Key Lime

Citrus aurantiifolia

VS
Pickerel Weed

Pickerel Weed

Pontederia cordata

Key Lime

Key Lime

Citrus aurantiifolia

The Key Lime is a small, thorny citrus tree typically reaching 6-13 feet in height. It produces small, highly aromatic limes with a thin, greenish-yellow rind. The pulp is juicy and acidic. Key Limes are primarily grown outdoors in warm climates for their fruit, which is used in pies, beverages, and other culinary applications. While it can be grown in containers, replicating its ideal outdoor conditions indoors is challenging. It is not naturally an indoor plant.

Rutaceae Southeast Asia
✨ Features: Aromatic foliage and fruit, used in culinary applications.
📖 Read Complete Key Lime Guide
Pickerel Weed

Pickerel Weed

Pontederia cordata

Pickerelweed is an aquatic perennial herb typically found in shallow water habitats like ponds, marshes, and streams. It features distinctive heart-shaped leaves and a prominent flower spike that blooms in summer. The plant grows from rhizomes, forming dense colonies. While primarily an outdoor plant, it is occasionally grown in large water gardens or aquariums. It is valued for its attractive foliage and flowers, which attract pollinators and provide habitat for aquatic wildlife.

Pontederiaceae North America, South America
✨ Features: Attracts pollinators, provides habitat for aquatic wildlife, helps filter water.
📖 Read Complete Pickerel Weed Guide

Quick Plant Comparison

Feature Key Lime Pickerel Weed
Light Full sun (6-8 hours of direct sunlight daily) Full sun to partial shade
Watering Every 1-2 weeks, depending on environmental conditions and pot size. Daily to maintain water levels
Humidity 50-70% 60-90%
Temperature 21-32°C 15-27°C
Care Level Expert Expert
Growth Rate Moderate Fast
Max Height 2-4 meters outdoors, 1-2 meters in containers indoors (with difficulty) 0.3-1 meter (outdoor, less in containers)
Pet Safety ❌ Toxic To Pets ❌ Toxic To Pets
Soil Well-draining citrus potting mix Heavy clay soil or aquatic planting mix
Beginner Friendly ❌ No ❌ No
Weekly Maintenance 30 minutes weekly 30 minutes weekly (including algae control, pruning, and water level maintenance)

🔬 Botanical Information — Comparing These Plants

Key Lime

Scientific Name Citrus aurantiifolia
Family Rutaceae
Native To Southeast Asia
Also Known As Key Lime, Mexican Lime, West Indian Lime
Leaves The leaves are small, oval-shaped, and glossy green. They are aromatic when crushed.
Flowers Key Limes produce small, white, fragrant flowers in spring. They can flower indoors with sufficient light, but fruiting is rare.

Pickerel Weed

Scientific Name Pontederia cordata
Family Pontederiaceae
Native To North America, South America
Also Known As Pickerelweed, Pickerel Weed, Heartleaf Pickerelweed
Leaves Heart-shaped (cordate) leaves, typically 10-25 cm long and 5-15 cm wide. The leaves are smooth, glossy green, and have prominent veins. They are attached to long petioles that emerge from the rhizomes.
Flowers Produces a dense spike of small, violet-blue flowers in summer. The flowers are about 1 cm long and have six petals. They are arranged spirally around the spike and bloom sequentially from the bottom up. Rarely flowers indoors.

📏 Size & Growth — Plant Comparison

Key Lime

Height 2-4 meters outdoors, 1-2 meters in containers indoors (with difficulty)
Spread 2-3 meters outdoors, 0.5-1 meter in containers indoors
Growth Rate Moderate
Growth Pattern The Key Lime tree is a small, shrubby tree with a rounded crown. It has thorny branches and a tendency to sucker from the base.

Pickerel Weed

Height 0.3-1 meter (outdoor, less in containers)
Spread 0.3-0.6 meters (spreads via rhizomes)
Growth Rate Fast
Growth Pattern Upright, emergent aquatic plant that grows from rhizomes, forming dense colonies in shallow water. It sends up stalks with heart-shaped leaves and flower spikes.

🌱 Propagation — Comparing Plant Growth

Key Lime

Methods: Seed, grafting, air layering, cuttings

Difficulty: Moderate

Tips: Use rooting hormone for cuttings and provide high humidity. Grafting is the most reliable method for fruit production.

Pickerel Weed

Methods: Division of rhizomes, Seed

Difficulty: Easy

Tips: Divide rhizomes in spring or early summer. Ensure each division has healthy roots and shoots. Plant in aquatic soil and keep submerged in water. Seeds can be sown in shallow water in spring.

✨ Benefits & Features — Comparing Plant Value

Key Lime

Key Limes are smaller and more acidic than Persian limes. They have a distinctive aroma and are a key ingredient in Key Lime pie.

  • ✓ Provides fresh limes for culinary use.
  • ✓ Aromatic foliage adds a pleasant scent to the garden.
  • ✓ Can be a rewarding challenge for experienced gardeners.
  • ✓ Offers a taste of the tropics in your own backyard.
  • ✓ The fruit is a good source of Vitamin C.
  • ⚠️ Toxic to pets

Pickerel Weed

Pickerelweed is a native aquatic plant that provides important habitat and food sources for wildlife. Its distinctive heart-shaped leaves and purple flower spikes make it an attractive addition to water gardens. It is also known for its ability to help filter and oxygenate water.

  • ✓ Provides habitat for aquatic wildlife
  • ✓ Attracts pollinators such as bees and butterflies
  • ✓ Helps to filter and oxygenate water in ponds and aquariums
  • ✓ Adds visual interest with its unique foliage and flowers
  • ✓ Contributes to a natural and balanced ecosystem in aquatic environments
  • ⚠️ Toxic to pets

📅 Maintenance Schedule — Plant Care Comparison

Key Lime

Repotting Every 2-3 years, or when the plant becomes root-bound.
Pruning Prune to maintain shape and remove dead or crossing branches. Prune after fruiting.
Fertilizing Citrus-specific fertilizer, diluted to half strength, every 4-6 weeks during the growing season (spring and summer)
Seasonal Care In winter, reduce watering and provide supplemental light if needed. Protect from frost. In summer, water more frequently and fertilize regularly.

Pickerel Weed

Repotting Divide and replant every 1-2 years to control spread and maintain vigor.
Pruning Remove dead or yellowing leaves regularly. Trim back excessive growth to control spread.
Fertilizing Aquatic plant fertilizer tablets or slow-release fertilizer formulated for aquatic plants, applied according to package instructions during the growing season (spring/summer).
Seasonal Care In winter, cut back dead foliage. In colder climates, rhizomes may need protection from freezing. In summer, ensure adequate water levels and sunlight.

🌞 Light Requirements

Key Lime

Full sun (6-8 hours of direct sunlight daily)

Low light tolerant: ❌ No

Pickerel Weed

Full sun to partial shade

Low light tolerant: ❌ No

💧 Watering Needs

Key Lime

Water thoroughly when the top inch of soil is dry. Overwatering can lead to root rot, indicated by yellowing leaves and a musty smell. Underwatering results in wilting and leaf drop. Ensure good drainage.

Pickerel Weed

Requires consistently moist to wet conditions. If grown in a container, ensure the pot is sitting in a tray of water or submerged in a larger water feature. Overwatering is not a concern as it is an aquatic plant. Underwatering will cause the leaves to wilt and brown.

🌡️ Temperature & Humidity

Key Lime

Temperature: 21-32°C

Humidity: 50-70%

Pickerel Weed

Temperature: 15-27°C

Humidity: 60-90%

🤔 Which Plant Is Right For You?

Key Lime

Key Lime

Citrus aurantiifolia
Care: Expert Time: 30 minutes weekly Beginner: No

Experienced gardeners in warm climates who want to grow their own limes.

✅ Choose This Plant If...

  • You live in a warm climate and can provide ample sunlight.
  • You enjoy the challenge of growing citrus trees.
  • You want to harvest your own Key Limes for cooking and baking.
  • You have a greenhouse or conservatory where you can control the environment.
  • You are willing to provide supplemental lighting and humidity indoors.

❌ Skip This Plant If...

  • You live in a cold climate with limited sunlight.
  • You are a beginner gardener.
  • You do not have the space or resources to provide the necessary care.
  • You have pets that may be poisoned by the plant.
  • You are looking for a low-maintenance indoor plant.
📍 Ideal Location: Outdoors in a sunny location. Indoors, a south-facing window with supplemental lighting.
🎨 Style: Tropical, Mediterranean
🏠 Apartment Friendly: Limited
⚠️ According to the ASPCA, citrus plants contain psoralens and essential oils that can cause gastrointestinal upset and dermatitis in dogs, cats, and horses. Symptoms include vomiting, diarrhea, drooling, and skin irritation.
Pickerel Weed

Pickerel Weed

Pontederia cordata
Care: Expert Time: 30 minutes weekly (including algae control, pruning, and water level maintenance) Beginner: No

Experienced gardeners with ponds, water gardens, or large aquariums who want to add a native aquatic plant.

✅ Choose This Plant If...

  • You have a pond or water garden and want a native plant.
  • You want to attract pollinators and wildlife to your water feature.
  • You need a plant that can tolerate consistently wet conditions.
  • You appreciate the unique heart-shaped foliage and flower spikes.
  • You are an experienced gardener looking for a rewarding aquatic plant challenge.

❌ Skip This Plant If...

  • You do not have a suitable aquatic environment (pond, water garden, large aquarium).
  • You are looking for a low-maintenance indoor plant.
  • You have pets that might ingest the plant, as it is toxic to them.
📍 Ideal Location: Outdoor pond, water garden, or large aquarium.
🎨 Style: Naturalistic, Cottagecore, Wild Garden
🏠 Apartment Friendly: No
⚠️ According to the ASPCA, Pickerel Weed contains calcium oxalates, which are toxic to dogs, cats, and horses. Symptoms include oral irritation, excessive drooling, vomiting, and difficulty swallowing.

🎯 Quick Verdict

Best for Beginners Neither ideal
Pet Friendly Neither - caution
Less Maintenance Similar effort
Apartment Friendly Check space

⚡ Key Differences Between These Plants

☀️

Key Lime needs full sun (6-8 hours of direct sunlight daily), while Pickerel Weed prefers full sun to partial shade.

📈

Key Lime has moderate growth, while Pickerel Weed grows fast.

💡 Pro Tips For Comparing These Plants

Key Lime Care Tips

Key Limes are challenging to grow indoors due to their high light and humidity requirements. They need very bright light, consistent watering, and protection from drafts. Fruit production indoors is unlikely without significant effort and supplemental lighting. Requires careful monitoring to prevent pests and diseases.

  • Provide well-draining soil to prevent root rot.
  • Water deeply but infrequently, allowing the soil to dry slightly between waterings.
  • Fertilize regularly during the growing season with a citrus-specific fertilizer.
  • Protect from frost and cold temperatures.
  • Prune regularly to maintain shape and remove dead or diseased branches.
❄️ Winter: Reduce watering frequency. Protect from frost. Provide supplemental light if needed.
☀️ Summer: Water more frequently. Fertilize regularly. Protect from intense afternoon sun in very hot climates.

Pickerel Weed Care Tips

Pickerelweed is best suited for outdoor water gardens or large aquariums. It requires full sun and consistently wet conditions. Indoor cultivation is challenging due to the need for specialized aquatic environments and intense lighting. It is an aggressive spreader and needs containment.

  • Ensure consistent water levels, especially during hot weather.
  • Provide full sun for optimal flowering.
  • Use aquatic plant fertilizer to promote healthy growth.
  • Control algae growth to prevent it from smothering the plant.
  • Protect rhizomes from freezing in colder climates.
❄️ Winter: Cut back dead foliage. In colder climates, protect rhizomes from freezing by moving them to a deeper part of the pond or covering them with mulch.
☀️ Summer: Ensure adequate water levels, especially during hot weather. Provide full sun for optimal flowering. Monitor for pests and diseases.

⚠️ Common Problems & Solutions — Plant Care Comparison

Key Lime

Common Issues: Spider mites, scale, aphids, root rot
Solutions: Spider mites: Increase humidity and use insecticidal soap. Scale: Manually remove and treat with horticultural oil. Aphids: Wash off with water or use insecticidal soap. Root rot: Improve drainage and reduce watering frequency.

Pickerel Weed

Common Issues: Algae growth, Nutrient deficiencies, Aphids, Root rot (if water quality is poor)
Solutions: Control algae with appropriate algaecides or by improving water circulation. Supplement with aquatic plant fertilizer. Treat aphids with insecticidal soap. Ensure good water quality to prevent root rot.

❓ Frequently Asked Questions — Comparing These Plants

Key Lime

What are the light requirements for Key Lime?

Key Lime trees demand bright, direct sunlight to flourish indoors. Ideally, place your tree near a south-facing window where it can receive at least 6-8 hours of sunlight daily. If natural light is insufficient, supplement with grow lights. Rotate the tree regularly to ensure even light exposure on all sides, preventing lopsided growth. Insufficient light can lead to leggy growth, reduced flowering, and poor fruit production. Consider using a light meter to measure the intensity of light reaching your tree. For optimal growth, aim for a light intensity of at least 2,000 foot-candles.

How do I care for Key Lime?

Key Lime trees thrive with bright light, ideally 6-8 hours of direct sunlight or equivalent grow lights. Water thoroughly when the top inch of soil feels dry, allowing excess water to drain. Use well-draining potting mix specifically formulated for citrus trees. Fertilize monthly during the growing season (spring and summer) with a citrus-specific fertilizer. Prune regularly to maintain shape and encourage fruiting. Provide adequate humidity by misting regularly or using a humidifier. Protect from drafts and sudden temperature changes. Repot every 2-3 years into a slightly larger pot. Monitor for pests like spider mites or scale and treat promptly. Ensure stable conditions and avoid overwatering. Proper pot size is crucial to prevent root rot.

How do I propagate Key Lime?

Key Lime trees can be propagated through stem cuttings or air layering. For stem cuttings, take a 4-6 inch cutting from new growth. Remove the lower leaves and dip the cut end in rooting hormone. Plant the cutting in a well-draining potting mix and keep it moist. Cover with a plastic bag to maintain humidity. Roots should develop in 4-6 weeks. For air layering, make a small incision on a branch and wrap it with moist sphagnum moss. Cover the moss with plastic wrap and secure it with tape. After several weeks, roots will form in the moss. Cut the branch below the roots and plant it in a pot. Provide warm temperatures and bright, indirect light during propagation. Ensure stable conditions and monitor moisture levels.

Pickerel Weed

What are the light requirements for Pickerel Weed?

Pickerel Weed thrives best in full sun, requiring at least six hours of direct sunlight daily. However, it can also tolerate partial shade, especially during the hottest part of the day. Insufficient light can lead to leggy growth, reduced flowering, and overall weaker plants.

How do I care for Pickerel Weed?

Pickerel Weed thrives in shallow water or moist soil. Plant in a pond, water garden, or a container submerged in water. Full sun to partial shade is ideal. Ensure the water is clean and well-oxygenated. Add aquatic plant fertilizer sparingly during the growing season (spring and summer). Remove dead leaves and flowers regularly.

How do I propagate Pickerel Weed?

Pickerel Weed can be easily propagated through division or cuttings.

Last updated: May 16, 2026 — Plant care data reviewed and verified by our editorial team.