Search for paulownia in North America and you will hit invasive-species warnings within a page or two. Search for paulownia in Spain, Italy or Australia and you will find commercial plantations and carbon projects. Both are true. The difference is almost never the climate — it is which paulownia you are talking about, and how it was propagated.
The species behind the warning
The plant behind the warnings is Paulownia tomentosa, sold in the United States as the princess tree or empress tree. It arrived as an ornamental in the 1840s — its light seed was famously used as packing material around shipped Chinese porcelain — and it naturalised aggressively. It colonises disturbed ground: roadsides, stream banks, rocky slopes and opened woodland.
University of Maryland Extension puts the reproductive capacity in stark terms, estimating a mature tree may produce on the order of 20 million seeds, with root sprouts capable of growing up to about 20 feet in a single season. Those are illustrations of capacity rather than a guarantee from every tree, but they explain the concern. Removal is also harder than it looks: cutting stops that season's seed but the tree resprouts readily from the stump and roots, and the US Forest Service notes that repeated cutting or herbicide treatment is often needed to exhaust the root system. Legal classification varies by state and county, so anyone dealing with it should check local rules.
Why plantation hybrids are a different proposition
Commercial paulownia plantations are not built on seedling P. tomentosa. They are built on selected and artificially crossed hybrids — in our case the Shan Tong lines developed in Shaanxi — and those hybrids are propagated asexually, by tissue culture and root cuttings, not by seed.
This is not a marketing detail, it is a biological necessity. Hybrid paulownia does not come true from seed: sow a Shan Tong seed and you do not get a Shan Tong tree. Asexual propagation is the only way to deliver genetically uniform, disease-free, true-to-type planting material at plantation scale, and it is why tissue culture has become the standard route for quality supply chains. Hybrids developed for the European market are selected specifically for plantation performance and are supplied on that basis.
One honest caveat: "selected for plantation use" is not the same as "zero risk everywhere". No fast-growing tree is risk-free in every ecosystem, and we would rather a buyer hear that from us than discover it from a regulator. The responsible sequence is: know the exact variety, check your national and regional invasive-species and import lists, and monitor the site after planting.
A buyer's checklist before you order
- Get the variety name in writing. "Paulownia" is a genus, not a product. Ask for the cultivar and its parentage.
- Ask how it is propagated. Seed-raised stock and clonally propagated hybrids are different products with different risk profiles.
- Check your own regulations first. Invasive-species and phytosanitary rules differ by country, state and even county. Confirm before you ship, not after.
- Insist on provenance documents. Counterfeit planting material sold under established varietal names is a real and documented problem — see our note on counterfeit Shan Tong in Europe.
- Match the variety to your site. A line bred for one climate will underperform or fail in another, regardless of how good the seedlings look on arrival.
Our position
We have bred and propagated high-resistance paulownia in Shaanxi for decades, and we supply clonally propagated hybrid planting stock for plantation use. We do not sell seed of Paulownia tomentosa, and we tell every partner the same thing we have written here: confirm your local rules before you plant, and buy material you can trace to a named source. A plantation is a ten-to-twenty-year commitment. The cheapest seedling is expensive if it turns out to be the wrong plant.
Sources & Further reading
- Invasives in Your Woodland: Princess Tree (University of Maryland Extension)
- Princess Tree identification and control (University of Maryland Extension)
Not sure which variety suits your region, or how to verify what a supplier is offering? Email paulownia@vip.126.com with your location, climate and goals — we will help you check before you commit.