We may earn revenue from the products available on this page and participate in affiliate programs. Learn More ›
Throughout the world, mulberry trees have been beloved for their delicious berries and as a symbol of healing, abundance, and providing gifts from nature. These large deciduous trees come in a variety of about 150 different species. Two of the most common types of mulberry trees—white mulberry (Morus alba) and red mulberry (Morus rubra)—have garnered attention in the United States for causing a host of problems. As a result, some communities, particularly in the Southwestern part of the country, have banned the trees.
However, some native mulberries are beneficial, and can thrive without causing so much trouble if grown in the right climate. So, mulberry tree identification skills are more important than ever. Learn where and why mulberry trees are illegal to ensure that you aren’t breaking any laws in your yard.
Why Are Mulberry Trees Illegal?
Over time, people began to realize the problems that mulberry trees could bring to a community. Key reasons the trees have been banned in some locations include how they can trigger a severe allergic reaction, create a mess, pose health issues, damage property, and harm the local ecology.
They can trigger allergies.
One of the most common reasons for banning mulberry trees is that the pollen they produce can cause a severe allergic reaction, including asthma, in some people. In fact, just walking under a pollinating mulberry tree can cause allergies to flare. The male flowers are the main culprit, since they produce a significant amount of pollen (more than many other trees), prompting several towns to ban the trees to protect residents. An entire tree might be male (the most problematic for pollen), female, or have both male and female flowers growing on the same tree.
Mulberry fruit creates a mess.
Mulberry trees can be such a messy nuisance that towns have no other choice but to ban them. When mulberries drop on the ground, the juice can stain sidewalks, driveways, roads, buildings, lawns, and anything else they come in contact with. In addition, these berries often create a sticky mess, especially when stepped on, and can ruin shoes, clothing, and vehicles.
The trees pose health concerns.
Not only does eating unripe berries cause health problems, but the sap from white mulberry trees can be toxic, especially when found on a mulberry tree leaf. Keep pets and children away from the trees to avoid any problems. One reason that jurisdictions ban this type of tree is the legal danger that can result when someone is harmed by it.
Mulberry roots can damage property.
As wild mulberry trees grow aggressively, their sprawling root systems can damage property, including walkways, sidewalks, building foundations, and underground pipes like water lines. Shallow mulberry tree roots do this as they expand to seek nearby sources of water and nutrients.
They spread aggressively and harm the local ecosystem.
Invasive white mulberry trees are known to spread quickly and take resources from native vegetation. This can devastate animals that depend on those plants for survival in the local ecosystem. Unfortunately, mulberry trees and their berries can attract pests and spread disease throughout the area. Another concern is that white mulberry trees can hybridize with the native red mulberry tree, posing a threat to the native species by weakening its genetic integrity.
The History Behind Mulberry Tree Bans
For centuries, “mulberry bushes” were a favorite choice because of their attractive foliage and scrumptious berries. However, concerns related to health, the environment, and messiness led to some regions in the country banning the trees.
“White mulberry (not the native red mulberry) was banned locally in several Southwestern cities in the 1980s and ’90s,” notes Doug Still, a certified arborist and tree consultant at This Old Tree. “One example is El Paso, Texas, which banned the tree based on the professional opinion of a local doctor—an allergy specialist—who declared that the trees are highly allergenic.” A period of over-planting male mulberries in public and residential spaces combined with wet conditions in the 1990s, leading to the trees flourishing a bit too much.
Known areas where the mulberry tree is banned or restricted include the following cities:
- Tucson, Arizona, banned white mulberry trees in 1984.
- Las Vegas, Nevada, made it illegal to plant white mulberry trees in 1991.
- El Paso, Texas, prohibited all new mulberry trees in 1992.
- Albuquerque, New Mexico, prohibits residents and commercial landowners from introducing new mulberry trees.
Not All Mulberries Are Invasive
White mulberry trees are invasive to the United States. Native to China, these exotic trees were brought to the United States during the colonial era to establish the silk industry. “The white mulberry was first imported to Virginia after the settlement of Jamestown,” explains Still. “King James I encouraged planting mulberries as a way to develop the silk industry, as silkworms love to eat the leaves of white mulberry. Due to the climate of North America, the silk industry was not enduring. However, the white mulberry trees escaped and thrived.” Indeed, invasive mulberry trees thrived so much that they posed ecological threats by invading woodlands and open forests.
However, red mulberry trees are native throughout the United States. They are far less aggressive than white mulberry, so it is critical to understand which species is growing when considering bans or restrictions or considering a mulberry in an area where they are not as problematic. Red full-grown mulberry trees are taller than white mulberry trees, reaching 60 to 80 feet with a spread of 50 feet. Their leaves are oval with 3-cornered tips, do well in moist soils, and produce delicious berries.
A Case for Planting Native Mulberry Trees (Where Legal)
Although valid reasons exist for banning and removing mulberry trees in certain areas, there are many benefits to planting native red mulberry trees if allowed. “Planting red mulberry is good for the native ecology,” notes Still. Here’s why:
- They attract wildlife, such as birds who feed on the berries and insects who find sustenance from the leaves.
- Because their high pollen content attracts bees and other pollinators, mulberry trees serve as an excellent companion plant for other fruit trees.
- While mulberry trees get a bad reputation for triggering allergies, the female trees do not produce pollen. Some experts even argue that female fruitless mulberry trees can remove more pollen from the air than they produce.
- Next, their sweet berries are delicious and nutritious, rich in vitamin C, K1, E, iron, and potassium. They are even considered a delicacy in some cultures. However, the berries are only safe to eat when ripe. Never eat them before they turn black.
Finally, mulberry trees are also attractive for their aesthetic value and the extensive shade they provide. The trees have lush foliage and vibrant berries to brighten up any landscape. So, planting a red mulberry in a region where they thrive naturally (and are not banned) can add to a landscape’s shade and appeal.
