Traveling With or Importing Plants? Read This First!

I've seen some conversations recently in the House Plant Hobbyist Facebook group about transporting plants across certain state lines and some folks seemed confused about or even hostile to the idea that your plants may have to be quarantined and inspected before you can bring them into say, California or Florida — or into the United States from out of the country, period.

These laws may seem silly or even outrageous, but they exist for a few very good reasons which I feel compelled to explain. As House Plant Hobbyists, we have a responsibility to be good stewards of the natural world from which our plants come, and part of that stewardship requires understanding and abiding by laws that are designed to protect it.

Imagine that you are moving to California and you have a truck loaded down with your houseplant collection. You stop at an agricultural inspection station where your plants are subject to inspection and even quarantine. Now imagine that you've ordered a rare plant you've been wanting from outside the country and it is seized and destroyed by the USDA at a customs station.

Seems harsh and unfair, right? It definitely feels that way, but it is done for two very good reasons: to protect local economies, and more importantly, the ecosystem.

When a plant is transported, whether it's from one state to another or from one country to another, three potential problems can arise: the spread of diseases, the spread of pests, and the introduction of invasive species. Agricultural import laws exist to help guard local economies and ecosystems from these threats.

First, plant diseases can be extremely damaging and easily spread if precautions aren't taken. For example, Chestnut blight was introduced to America by nursery plants from Japan in the early 20th century and wiped out entire forests in the eastern United States. Erwinia blight, which commonly affects Hope Philodendron (Thaumatophyllum bipinnatifidum) can kill entire crops of apple and pear trees. Citrus canker originated in Southeast Asia and spread by plant exports to Australia and the United States where it continues to kill off entire crops of citrus fruit, which can devastate the lives of people in states where citrus farming is a way of life.

The spread of damaging pests is another concern. In the 1990s, the glassy winged sharpshooter (Homalodisca vitripennis, a species of leafhopper) hitchhiked into California onboard houseplants and proceeded to kill off grape crops. This harmful insect likes to hide in Ficus, Begonias, Asplenium, and many other common houseplants. Another harmful pest are zebra mussels (Dreissena polymorpha). They are commonly spread in the ballast tanks of ships, but can also be spread by transporting aquatic plants. They breed rapidly, overtake entire waterway ecosystems, and have cost billions of dollars in damage in the United States alone.

While the zebra mussel is both a pest and an invasive species, it is important to mention that many houseplants can become invasive species in and of themselves. A harmless houseplant confined to a pot in one place is an aggressive invader somewhere else where it grows rapidly and competes for resources with native plants. Without natural checks on their population, they grow out of control and choke out local ecosystems. Inch plant (Tradescantia spp.), Monstera, snake plants (Sansevieria spp.), pothos (Epipremnum aureum), mother of millions (Bryophyllum spp.), prickly pears (Opuntia spp.) and many other common houseplants all have the potential to become invasive species if they "escape" in a favorable climate. Since the rise of invasive species is one of the major causes of extinctions, it is important to prevent certain plants from growing where they can easily take over and become a threat to native ecosystems and potentially lead to the death of other species.

It may not seem like it, but being a House Plant Hobbyist carries with it a certain measure of responsibility, especially if you ever transport, ship, or import plants. It is prudent to always exercise caution and to respect the laws that help protect the economy and environment from the impact of the spread of plant diseases, pests, and invasive species. Caring about where your plants come from and where they go will help you to be a responsible hobbyist and a good steward of the natural world we all share.

Here are a few resources to learn more about importing and transporting plants in the U.S.:

USDA APHIS (United States Department of Argiculture Animal and Plant Health Inspection Service) page on importing plants.

USDA APHIS page about PPQ (Plant Protection & Quartentine)

USDA APHIS Plant Pest and Disease Programs

NPB (National Plant Board) page including information containing laws and regulations for transporting for each U.S. state