I occasionally hear people ask if they’re allowed to grow mulberry trees and I was curious to find out the reason behind it. The problem is, there’s not a lot of information out there. So, I did some even deeper digging. Here’s what I found about if you can plant mulberry trees.
Mulberry trees were made illegal in several states in the 1980s and 1990s as they produced large amounts of pollen and their fruit stained streets and sidewalks. People also found they had a stronger reaction to mulberry pollen than most other pollen types and the trees are fairly invasive.
While this helps explain why mulberries are illegal, which parts of the mulberry tree are bad, and in which states were the trees made illegal? Let’s take a closer look.
Why Are Mulberry Trees Bad?
While there are some mulberries native to the US (such as the red mulberry) and don’t cause as much of an issue, the notorious one is the white mulberry.
White mulberries are native to the temperate regions of Asia and were a popular, fast-growing landscaping tree for houses and public areas in the southwest US leading up to the 1980s and 1990s.
It was then that people started finding strong reactions to their pollen and their sidewalks, driveways, and kitchen floors stained with pollen and fallen fruits (tracked indoors from shoes). As a result, significant maintenance was often required.
Additionally, birds favored the fruits and would spread the seeds through their manure, making the tree fairly invasive.
With the 1990s being a particularly wet season, mulberry trees took off in growth. It was around this time some states began banning them.
El Paso banned the planting and sale of the trees in 1992, following other Southwestern cities such as Las Vegas, Tucson and Albuquerque, which all cracked down in the late 1980s and early 1990s on the allergy-causing amounts of pollen released by male trees.Danielle Prokop, El Paso Matters
Here are some of the cities I was able to find that banned selling or planting mulberry trees:
- Tucson, AZ banned in 1984
- Las Vegas, NV banned in 1991
- El Paso, TX banned in 1992
If you’d like to find out if your area can have mulberry trees, I suggest contacting your local nursery, professional orchard, or cooperative extension service.
Any mulberries that were planted before the ban are nearing the end of their life, so their numbers have been declining.
There are currently arguments both for and against mulberry trees.
Some say they’re a great companion plant for the garden, attracting plenty of pollinators and boosting the fruit yields of other plants.
“Some home owners complain that mulberry fruit creates a gooey, staining mess, but intelligent placement (avoiding the driveway and play areas) will minimize this draw-back. Also, if the backyard ecosystem is in good health, the abundant wildlife will greedily consume extra berries.”Toby Hemenway, Gaia’s Garden
Others say the tree is invasive and problem-causing, instead preferring native trees such as the honey mesquite.
Why Are Mulberry Trees Special?
Mulberry trees are an extremely useful plant as their leaves are the sole food of silkworms, which cocoons provide all of our silk.
Originally, silk was developed in ancient China and created the longest trade routes (The Silk Road). Civilizations from all around preferred this silk, including Romans, Greeks, and Egyptians.
Since then, silk is still being made the exact same way.
Silk is still a valuable market, with the single type of fabric generating an annual revenue of around $23 billion (source).
Because the silkworm’s cocoon needs to be regulated from outside temperature swings, silk clothing retained these properties. This means silk stays cooler in warm weather, and warmer in cool weather (source).
Why Can’t You Find Mulberry Fruits In Stores?
It’s difficult to find mulberries in grocery stores as the fruit is tough to harvest and only lasts 2-4 days, even after being refrigerated (source). This makes the process of harvesting, handling, shipping, and shelving the fruits often not worth the cost.
Fortunately, mulberry trees are fairly easy to grow in many climates (USDA zones 4-8) and are still popular in some US states.
If you’d like to order a mulberry tree, I suggest the everbearing mulberry variety. You can find it at the Fast Growing Trees nursery (but make sure you can grow it in your area first)!
While I include mulberry trees in some of my permaculture designs, I suggest you first check if you can legally grow them in your area. While they’re amazing plants in the garden (attracting pollinators, serving as espaliers, etc), they can have negative effects if planted incorrectly or if the wrong variety is used.