The question of whether an elderberry is a bush or a tree highlights a common ambiguity in botanical classification. Elderberry plants belong to the genus Sambucus. They are technically best described as fast-growing, multi-stemmed shrubs that possess the capacity to develop into small, single-trunked trees under favorable conditions. This dual growth habit is the reason for the confusion, as the plant’s appearance depends heavily on its species, age, and local environment.
Defining the Growth Habit: Shrub Versus Tree
The distinction between a shrub and a tree is not always absolute, but it is typically based on structural growth patterns. A classic tree is a woody plant that develops a single, dominant trunk and grows to a significant height. Trees exhibit a characteristic apical dominance, meaning the central stem grows most vigorously.
A shrub, by contrast, is a smaller woody plant defined by multiple stems that emerge directly from the base near the ground. Shrubs are generally lower in height and lack a single, clear trunk. The elderberry often begins its life as a dense, multi-stemmed shrub.
Over many years, however, the central stems of an elderberry can mature and thicken, becoming woody and bark-covered to the point where they resemble a small, short trunk. This structural development allows some elderberry specimens to meet the morphological criteria for a small tree. This transitional growth habit is why the elderberry is often categorized as a large shrub or small tree.
Key Species and Their Typical Forms
The two most widely referenced species, European and American elderberry, exhibit these growth forms differently. Sambucus nigra, the European Elderberry, is the species most likely to be referred to as a small tree. Under ideal conditions, S. nigra can grow vigorously, reaching heights of 15 to 20 feet and developing a more substantial, tree-like trunk over time.
Sambucus canadensis, the American Elderberry, is more reliably a large shrub. This species is typically shorter, rarely exceeding 8 to 10 feet tall, and maintains a distinctively multi-stemmed, clump-forming growth habit. While both species share many characteristics, their mature size causes the European variety to more frequently blur the line with tree classification.
Essential Identification Features
Regardless of its height or form, the elderberry plant can be identified by several specific features. A unique marker is the spongy, white pith that fills the center of young stems and branches; this soft material is clearly visible when cut and is a reliable characteristic for the genus Sambucus.
The leaves are also distinctive, growing oppositely on the stem and being pinnately compound, meaning they are divided into smaller leaflets arranged along a central stalk. Each leaf typically consists of five to nine serrated leaflets. In late spring to early summer, the plant produces large, creamy-white flowers in flat-topped clusters called cymes.
The bark of the elderberry is light gray-brown and features numerous raised, wart-like bumps known as lenticels, which are visible even on younger twigs. As the plant ages, the bark becomes rougher and develops shallow furrows. These physical markers allow for accurate identification even when the plant’s height is confusing.
Safety and Toxicity Considerations
While the ripe berries and flowers of the elderberry are commonly used in food and wellness products, other parts of the plant are considered toxic. The leaves, stems, roots, and the seeds within the berries contain cyanogenic glycosides, specifically a compound called sambunigrin. These naturally occurring compounds can release small amounts of hydrogen cyanide when digested, potentially causing nausea, vomiting, and diarrhea.
Due to the presence of these compounds, the berries must be fully ripe and properly prepared before consumption. Heating the berries is necessary, as cooking effectively breaks down the cyanogenic glycosides, rendering the fruit safe. Foraging for elderberries requires careful attention to remove all stems, leaves, and any unripe green berries before processing the fruit through heat.