American Elm (Ulmus Americana ‘Lewis & Clark’ PRAIRIE EXPEDITION)

Plant: Table of Contents

American Elm (Ulmus americana ‘Lewis & Clark’ PRAIRIE EXPEDITION)

The American Elm, scientifically known as Ulmus americana ‘Lewis & Clark’ PRAIRIE EXPEDITION, is a captivating and historically significant tree. It is deeply intertwined with the exploratory journeys of Lewis and Clark, symbolic of the American frontier, and a pioneering elm variety. Its rich historical background, coupled with its exceptional qualities, makes it a compelling species for enthusiasts, botanists, and gardeners alike.

In this comprehensive guide, we will delve into the cultural significance, key attributes, ideal growing conditions, and tips for cultivating the American Elm. Furthermore, we will explore its historical connections, propagation methods, common pests and diseases, and valuable tips from botanists.

What is Plant: American Elm (Ulmus americana ‘Lewis & Clark’ PRAIRIE EXPEDITION)

The American Elm, Ulmus americana, is a deciduous tree native to eastern North America. It typically grows to a height of 60 to 80 feet and has a broad, vase-shaped crown. The ‘Lewis & Clark’ PRAIRIE EXPEDITION cultivar holds historical significance, named after the notable explorers Meriwether Lewis and William Clark.

Key Takeaways – American Elm (Ulmus americana ‘Lewis & Clark’ PRAIRIE EXPEDITION)

Before diving into the intricacies of this remarkable tree, let’s highlight some key takeaways:

  • Botanical Name: Ulmus americana ‘Lewis & Clark’ PRAIRIE EXPEDITION
  • Common Name: American Elm
  • Historical Significance: Associated with the Lewis and Clark expedition and the American frontier
  • Attributes: Broad, vase-shaped crown; deciduous; deep green foliage
  • Cultivation Considerations: Sunlight, Water, Soil, Fertilizer, Pruning, Propagation, Container Gardening
  • Pests and Diseases: Vulnerable to Dutch Elm Disease and Elm Leaf Beetle
  • Botanist Tips: Insights for maintaining the health and vigor of the American Elm
  • Fun Facts: Intriguing and lesser-known aspects of this historical and botanical marvel


The American Elm holds a special place not just in botanical circles but also in the historical narrative of America. Its cultural significance, combined with its striking appearance, has cemented its popularity among plant enthusiasts and conservationists. Let’s explore its cultural uses and significance.


Ornamental Value

The American Elm, particularly the ‘Lewis & Clark’ PRAIRIE EXPEDITION variety, is treasured for its ornamental appeal. Its elegant form, deep green foliage, and historical association make it a prized addition to landscapes, botanical gardens, and historical sites.

Historical Significance

Due to its association with the Lewis and Clark expedition and the American frontier, the American Elm holds immense historical and cultural significance. It serves as a reminder of the pioneering spirit that shaped the nation and the botanical discoveries that accompanied these exploratory journeys.


Water is an essential factor in the successful cultivation of the American Elm. While it is generally a hardy tree, adequate hydration is crucial for its overall health and vigor, especially during its formative years. Let’s delve into the watering requirements for this majestic tree.

Watering Guidelines

Young Trees

For newly planted American Elm trees, it is important to ensure consistent moisture in the soil. Regular watering, especially during dry spells, is essential to support the establishment of young trees. Table 1 provides a general guideline for watering frequency based on the tree’s age and environmental conditions.

Mature Trees

Mature American Elm trees often develop a deep and extensive root system, enabling them to withstand periods of moderate drought. However, during prolonged dry periods, providing supplemental water can contribute to the tree’s overall health and vitality. Table 2 offers recommendations for watering mature American Elm trees.

Table 1: Watering Frequency for Young American Elm Trees

Age of Tree Watering Frequency
0-1 Year 2-3 times per week
1-2 Years 1-2 times per week
2-3 Years Once per week

Table 2: Watering Guidelines for Mature American Elm Trees

Season Watering Frequency
Spring As needed
Summer During dry spells
Fall Before winter

Tip: When watering American Elm trees, it is important to ensure that the soil is well-draining to prevent waterlogging, which can lead to root rot and other detrimental conditions. A layer of organic mulch around the base of the tree can help retain soil moisture and regulate temperature.


The American Elm, including the ‘Lewis & Clark’ PRAIRIE EXPEDITION variety, thrives in bright, full sunlight. Adequate sunlight is crucial for the tree’s growth, development, and overall well-being. Understanding its sunlight requirements is paramount for cultivating this historical and botanical treasure.

Sunlight Requirements

Full Sun Exposure

American Elm trees prefer full sun, which generally entails at least six to eight hours of direct sunlight daily. In locations with hot afternoon sun, providing some shade during the peak hours can be beneficial, especially for young trees.

Partial Shade Tolerance

While American Elm trees flourish in full sun, they also exhibit a degree of tolerance to partial shade. However, prolonged lack of sunlight can affect the tree’s overall growth and may lead to sparse foliage and reduced vigor.


Proper and timely fertilization is essential for maintaining the health and vitality of the American Elm, particularly the ‘Lewis & Clark’ PRAIRIE EXPEDITION variety. By providing the tree with essential nutrients, gardeners can ensure robust growth, strong root development, and improved resistance to environmental stressors. Let’s explore the fertilizer requirements and best practices for nourishing the American Elm.

Fertilization Guidelines


Young American Elm trees benefit from an annual application of balanced, slow-release fertilizer during the early spring months. Mature trees may receive fertilizer once every 2-3 years, depending on the soil quality and overall growth.

Nutrient Balance

When selecting a fertilizer for American Elm trees, opt for a balanced formulation, such as a 10-10-10 NPK blend or a specially formulated tree fertilizer. The balanced nutrient content supports foliage development, root growth, and overall tree vitality.

Application Method

Fertilizer should be evenly distributed around the tree’s drip line, avoiding direct contact with the trunk. Water the tree thoroughly after fertilization to ensure the nutrients penetrate the soil and reach the root zone.


The soil composition and quality play a pivotal role in the successful cultivation of the American Elm, providing the essential support and nutrients for the tree’s growth. Understanding the ideal soil conditions and adopting appropriate soil management practices are imperative for nurturing healthy and resilient American Elm trees.

Soil Composition

Well-Draining Soil

American Elm trees thrive in well-draining soil that is rich in organic matter. A loamy soil texture, which combines sand, silt, and clay in balanced proportions, provides an ideal growing medium for these trees.

pH Considerations

The preferred soil pH for American Elm trees ranges from slightly acidic to mildly alkaline, generally between 6.5 and 7.5. Conducting a soil pH test can help determine the need for amendments to achieve the optimal pH range.

Soil Amendments

Amending the soil with organic matter, such as compost or well-rotted manure, enhances its fertility and structure. It improves water retention, promotes beneficial microbial activity, and fosters a conducive environment for the tree’s root development.


Pruning is an essential practice for maintaining the structural integrity, aesthetics, and overall health of American Elm trees. By implementing proper pruning techniques, gardeners can manage the tree’s growth, mitigate potential hazards, and enhance its ornamental appeal. Let’s explore the key considerations for pruning the American Elm, including the ‘Lewis & Clark’ PRAIRIE EXPEDITION variety.

Pruning Guidelines


Pruning of American Elm trees, especially the ‘Lewis & Clark’ PRAIRIE EXPEDITION variety, is typically carried out during the dormant season, preferably in late winter to early spring. This timing minimizes stress on the tree and reduces the risk of disease transmission.

Pruning Objectives

The primary objectives of pruning American Elm trees include:

  • Removing dead, diseased, or damaged branches
  • Shaping the tree’s canopy
  • Thinning crowded or crossing branches
  • Elevating the canopy to improve clearance

Disease Prevention

Pruning tools should be disinfected before and after use to prevent the spread of diseases. Additionally, promptly removing and destroying any pruned material showing signs of disease is crucial for minimizing disease incidence.


Propagating the American Elm, including the ‘Lewis & Clark’ PRAIRIE EXPEDITION variety, allows for the expansion of its historical and horticultural legacy. By employing various propagation methods, such as seeds, cuttings, or grafting, enthusiasts can preserve and proliferate this captivating tree. Let’s explore the propagation techniques for the American Elm and delve into the best practices for successful cultivation.

Propagation Methods


In the wild, American Elm trees propagate through the dispersal of seeds. To propagate the ‘Lewis & Clark’ PRAIRIE EXPEDITION variety from seeds, collect ripe seeds in the fall, stratify them in a cool, moist medium for 60-90 days, and sow them in well-draining potting mix in early spring.


Softwood or hardwood cuttings can be utilized to propagate American Elm trees. Softwood cuttings are best taken in early summer, with a rooting hormone applied to expedite root formation. Hardwood cuttings are collected during the dormant season and require a longer period for root development.


Grafting offers a reliable method for preserving specific traits of the ‘Lewis & Clark’ PRAIRIE EXPEDITION variety. The preferred approach is whip-and-tongue grafting, which entails joining a scion of the desired variety onto a compatible rootstock, fostering a new tree with identical genetic characteristics.

Container Popularity

The American Elm, including the ‘Lewis & Clark’ PRAIRIE EXPEDITION variety, is increasingly gaining popularity as a container plant. Its historical significance, elegant appearance, and adaptability to container cultivation make it an appealing choice for both enthusiasts and botanical institutions. Let’s explore the container gardening potential and considerations for the American Elm.

Container Gardening Considerations

Suitable Container

Select a spacious container with adequate drainage holes to accommodate the root system of the American Elm. A sturdy, weather-resistant material, such as glazed ceramic or high-quality plastic, is recommended for long-term container cultivation.

Soil Mix

Prepare a well-draining, nutrient-rich potting mix suitable for woody plants. A blend of peat moss, perlite, compost, and coarse sand provides a conducive medium for the tree’s growth and minimizes the risk of waterlogging.


Position the container-grown American Elm in a location that receives ample sunlight, generally in a south- or west-facing aspect. Regularly rotate the container to ensure even exposure to sunlight and promote balanced growth.

Fun Fact: The American Elm has historically been associated with street and urban plantings, adorning many cityscapes across the United States. Its adaptability to container cultivation reflects its enduring appeal in diverse environments.

Common Diseases

Despite its historical significance and ornamental value, the American Elm, including the ‘Lewis & Clark’ PRAIRIE EXPEDITION variety, is susceptible to various diseases that can threaten its health and longevity. Understanding the common diseases and implementing preventive measures is crucial for safeguarding these iconic trees. Let’s explore the prevalent diseases and effective management strategies.

Disease Diagnosis

Dutch Elm Disease

Dutch Elm Disease (DED) is a devastating fungal disease caused by the pathogen Ophiostoma novo-ulmi. It is transmitted by bark beetles and disrupts the vascular system of the tree, leading to wilting, yellowing foliage, and ultimately, tree death. Rapid diagnosis and prompt intervention are essential for managing DED.

Elm Yellows

Elm Yellows, also known as Elm Phloem Necrosis, is caused by a phytoplasma and affects the tree’s phloem tissue, leading to symptoms such as leaf discoloration, stunted growth, and overall decline. There is no cure for Elm Yellows, making preventive measures critical for protecting susceptible trees.


Anthracnose, caused by various fungal pathogens, manifests as dark, irregular lesions on the leaves, often accompanied by premature leaf drop and defoliation. While anthracnose can impact the American Elm’s aesthetics, it is generally not fatal and can be managed through cultural practices and fungicidal treatments if necessary.

Common Pests

In addition to diseases, American Elm trees, including the ‘Lewis & Clark’ PRAIRIE EXPEDITION variety, are vulnerable to infestations by various pests, including insect pests and mites. Identifying the common pests and adopting integrated pest management strategies is essential for preserving the health and vitality of these historical and horticultural treasures. Let’s explore the prevalent pests and effective pest management techniques.

Common Pest Identification

Elm Leaf Beetle

The Elm Leaf Beetle (Xanthogaleruca luteola) is a significant pest that targets elm trees, feeding on the foliage and causing characteristic skeletonization of leaves. Larvae and adult beetles can defoliate the tree, affecting its overall vigor and aesthetic appeal.

Spider Mites

Spider mites are microscopic pests that can infest American Elm trees, particularly in hot and dry conditions. They cause stippling and discoloration of the leaves, leading to reduced photosynthetic capacity and potential stress on the tree.

Integrated Pest Management

Implementing a holistic approach to pest management, including cultural practices, biological controls, and judicious use of targeted insecticides, is essential for minimizing pest damage while preserving beneficial natural predators and pollinators.

Botanist’s Tips

As botanists and horticulturists deeply committed to the preservation of botanical heritage and the dissemination of valuable plant care insights, we offer the following tips for enthusiasts and gardeners devoted to the cultivation of the American Elm, particularly the ‘Lewis & Clark’ PRAIRIE EXPEDITION variety.

Botanist’s Insights

Disease Resistance

When selecting American Elm trees for planting, prioritize disease-resistant varieties, such as the ‘Lewis & Clark’ PRAIRIE EXPEDITION, to mitigate the risk of Dutch Elm Disease and other devastating pathogens.

Soil Health

A focus on soil health, including periodic soil testing, organic amendments, and mulching practices, is instrumental in fostering robust and resilient American Elm trees with strong root systems and optimal nutrient uptake.

Historical Awareness

Embrace the historical and cultural significance of the American Elm as an homage to the pioneering spirit of early botanical explorations and the exploration heritage of the Lewis and Clark expedition.

Fun Facts

The American Elm, with its ‘Lewis & Clark’ PRAIRIE EXPEDITION variety, is not only a botanical marvel but also inspires intrigue and fascination through its historical connections and lesser-known attributes. Let’s uncover some engaging and lesser-known facts about this exceptional tree.

Intriguing Insights

  1. Historical Traverses: The American Elm has witnessed and endured pivotal moments in American history, from early exploration to urban development, symbolizing resilience and adaptability.
  2. Botanical Explorations: The ‘Lewis & Clark’ PRAIRIE EXPEDITION Elm pays homage to the cherished legacy of plant exploration and the quest for discovery inherent in botanical expeditions.
  3. Historic Street Trees: American Elm trees were once a ubiquitous sight along city streets, adorning urban landscapes with their graceful forms and providing shade and visual appeal.
  4. Conservation Efforts: Ongoing efforts to develop disease-resistant varieties and preserve the genetic diversity of the American Elm showcase the enduring commitment to its conservation and propagation.

Links to External Resources

To further your understanding and appreciation of the American Elm, including the ‘Lewis & Clark’ PRAIRIE EXPEDITION variety, we recommend exploring the following external resources for valuable insights and educational content:

  1. The Morton Arboretum – American Elm
  2. United States Department of Agriculture – Plant Guide for American Elm
  3. University of Kentucky – Dutch Elm Disease
  4. National Park Service – Lewis and Clark National Historic Trail

In conclusion, the American Elm, particularly the ‘Lewis & Clark’ PRAIRIE EXPEDITION variety, stands as a testament to the intertwined narratives of botanical exploration, historical significance, and horticultural admiration. Its enduring charm, adaptability, and contributions to the landscape evoke a profound sense of appreciation and reverence for this monumental tree. As we continue to celebrate its rich heritage and sustain its iconic presence, let us embrace the enduring legacy of the American Elm in all its historical, cultural, and botanical splendor.

Picture of Peter Taylors

Peter Taylors

Expert botanist who loves plants. His expertise spans taxonomy, plant ecology, and ethnobotany. An advocate for plant conservation, he mentors and educates future botanists, leaving a lasting impact on the field.