When I was a kid, my dad sometimes brought me bits of plant life from his work trips around the country. I was more interested in those kinds of souvenirs than anything from an airport gift shop.
They were nothing ecologically-sensitive or fancy. Just nuts or seed pods from trees in a public park, or sprigs of foliage from a buffer strip along a parking lot. I remember a husk of horse chestnuts from Washington DC, a handful of Agave bulbils from San Diego, and lots of pine cones.
It turns out I now travel the same way. But unlike my childhood gifts, which I usually dried and arranged on what I dubbed the “science shelf” in my bedroom, I’m more interested in things I can propagate. I find that having a story behind my houseplants gives me a deeper interest than just buying them at a garden store.
So, on a recent trip to the Big Island of Hawaii, I took the opportunity to collect some really interesting and beautiful plants, with the added challenge of following the stricter regulations of traveling over an ocean with cuttings and seeds.
Traveling eco-safe with plants
Over the years we’ve learned more about the risks of moving living things around the world. Every day, millions of tons of timber, grains, livestock, plants, flowers and produce are shipped across the oceans. Many have escaped into the wild, becoming invasive species that overrun native ecosystems. Others harbor hidden pests that could wipe out species or destroy agricultural industries. Consider the American Chestnut, a once-dominant North American tree that was wiped out a century ago by an exotic fungal disease, or the emerald ash borer, a bug from Asia that is steadily eradicating North American ash trees.
As much as I love collecting plants, it’s important to me to do it safely and legally. I would hate for my legacy of life on Earth to have been personally responsible for destroying a species. So I follow the regulations and take some additional precautions. That also means being above-board with the USDA and any other relevant agencies.
Safe vs unsafe plants
Living in Colorado, it’s unlikely a tropical plant brought from Hawaii would survive outdoors and become invasive. These are strictly to become houseplants, isolated from the local flora. But that’s not the case if you’re in a balmier state, like Florida, Texas, California, or even marginally similar places like Arizona or Oregon, so there will be stricter considerations than what I describe here.
A few categories of plants contain species that are remarkably adaptable and widespread, and the U.S. Department of Agriculture prohibits their transport entirely. They can also harbor viruses, fungi or insect pests that can more easily jump from one climate to another. That list includes grasses, sedges and cacti, as well as most commercially-important vegetables and fruit. In the case of cacti, an extremely destructive cactus moth was brought to Hawaii to eradicate an invasive Opuntia species, burrowing deep into the flesh and eating it from the inside. The moth could put several North American prickly pear species at risk.
Plants must be soil-free
Moving soil is a concern unto itself. A handful of wild soil can contain hundreds or thousands of species bacteria, fungi, viruses, insects, worms, nematodes, slugs and snails or various pest eggs. Some of these species may not even be documented by science yet, and it’s likely there are organisms there that can live in both tropical and cold climates. Due to the incalculable risks, moving soil into the U.S. mainland from overseas is banned entirely. Plants need to be bare-rooted and washed, or better yet, restricted to dry seeds and soil-free cuttings. Potting media, which is an artificial product made of pasteurized dead plant material and fillers, is not soil, and that’s what nurseries cleared for shipping to the U.S. will use.
My experience collecting plants in Hawaii
Hawaii has an impressive variety of landscapes and microclimates. In the rainforest biomes, you can really get a sense of the risks posed by invasive species when you realize that almost all the trees and vines growing there came from someplace else. From the dominant eucalyptus trees to the ubiquitous pothos vines, the wettest zones are basically a hodgepodge of aggressive plants from jungles around the world. The ecosystem there is basically a brand new assortment of organisms, and we’re yet to see how it develops over coming generations.
The resorts and villages, meanwhile, are manicured collections of what I basically think of as houseplants. The giant banyan trees, with curtains of aerial roots dangling from the branches, come from a group of Ficus tree species that grow in the wild by sprouting from seed on branches of mature trees and eventually smothering them with their roots (strangler figs). They include the familiar “weeping fig” and “rubber tree” which we know of as houseplants. There are hedges of hibiscus, beds of crotons and bromeliads, Monstera vines climbing the trees. There are Sansevierias and Heliconias. Aloes and Agaves. Everything you’ve seen in your local nursery’s tropical section is now here, giant-sized.
And that’s where I got almost all of my cache. The gardeners coming through to trim the plants on practically a daily basis provided lots of cuttings, and the seeds scattered around the ground made good finds. Tropical trees tend to be heavy seed producers and nearby sidewalks and streets are littered with them.
Whenever I found a cache of seeds or downed branches that looked appealing, I looked the species up to make sure I thought I could grow it at home. Before the week was up I compiled a cooler’s worth of seeds and cuttings, bagged, labeled and ready to go.
Going through the USDA checkpoint
Getting live plants to the mainland is an intimidating thought, given that you can’t even bring an orange for lunch onto an airplane headed to North America. But the regulations are there to prevent specific pests from getting across, and due to the millions of pounds of commercial food crops shipped around the world each year, some of them have unfortunately already gotten to Hawaii—but some have not yet reached the continental U.S. Others have reached the continental U.S. but aren’t yet in Hawaii, so restrictions go both ways. Additionally, there are a lot of pests that hide in fruit in particular. If you want seeds, which are less hospitable to stowaways, just make sure to scrub the flesh off and put clean, dry seeds in a package for inspection.
Cuttings are, similarly, surprisingly easy to bring. As long as they don’t come from a list of prohibited plants (which includes plants in the citrus family, cacti and grass), and they’re not endangered (which they wouldn’t be because I only collected cultivated plants), they’re likely permitted.
In this case, you want to remove any leaves with bruises or spots that could potentially harbor disease. Luckily, many tropical plants are vigorous enough that they can grow from a segment of stem without any leaves at all.
It’s probably important that you are able to identify the species you are working with, in case the USDA agent doesn’t recognize it and wants to exclude it. Or, worse, the USDA agent could accidentally miss a prohibited species and allow it through. Make sure you read and can understand the guidelines. If you have any doubt, you can call the Hawaiian USDA office, which I did, and get connected to someone who can offer guidance.
I went through the checkpoint at the Kona airport on the Big Island with 27 types of plants and cuttings. The agent only blocked one item from getting through—a bag of Crinum asiatica seeds that were still very green and fleshy. She picked out a couple other seeds here and there that looked damaged, letting me keep the rest. She took a close look at some agave bubils to make sure they weren’t some type of cactus, and that was that. After inspection, the plants went into a cooler that was tagged with a USDA sticker, and arrived in Denver for me to process and propagate.
Additional safeguards
After getting my cuttings home, I’m still not going to take any chances that some unusual organism slips through. They are being nursed and propagated indoors, in most cases under a plastic humidity dome. That way I’ll be able to observe them for some time as they get growing. You can read a bit about general plant propagation techniques here. But in my next post, I’ll write more about bringing these particular little stems and seeds to life.