En Español

Q. Who is Mr. Smarty Plants?

A: There are those who suspect Wildflower Center volunteers are the culpable and capable culprits. Yet, others think staff members play some, albeit small, role. You can torture us with your plant questions, but we will never reveal the Green Guru's secret identity.

Help us grow by giving to the Plant Database Fund or by becoming a member

Did you know you can access the Native Plant Information Network with your web-enabled smartphone?


Ask Mr. Smarty Plants

Ask Mr. Smarty Plants is a free service provided by the staff and volunteers at the Lady Bird Johnson Wildflower Center.

Search Smarty Plants
See a list of all Smarty Plants questions

Please forgive us, but Mr. Smarty Plants has been overwhelmed by a flood of mail and must take a break for awhile to catch up. We hope to be accepting new questions again soon. Thank you!

Need help with plant identification, visit the plant identification page.

rate this answer
1 rating

Thursday - August 23, 2007

From: Riverhead, NY
Region: Northeast
Topic: Non-Natives
Title: Distribution of Non-Native Royal Empress Tree
Answered by: Jimmy Mills


I was wondering if you could give me the statistics for the Royal Empress Tree in the Long Island area. I have two and have read numerous articles online regarding them being invasive through the root system and seed pods that will sprout after the purple/blue flowers in the spring. The trees I have are approx 2 years old. What is the reproduction rate (invasiveness) on Long Island for this kind of tree? Any information you could give me regarding care, maintance, and removal would be greatly appreciated.


Empress Tree (Paulownia tormentosa), aka Princess Tree, is native to China, and is distributed in 25 states in the US from Massachusetts to Florida and west to Texas. In most of its range, it is considered an invasive plant. However, the Invasive Plant Council of New York State does not list it as such, but the Invasive Plant Atlas of New England does.

As you have probably noticed from your two plants, growth is very rapid. Your plants could become reproductive in six to eight years, and at that time, each could potentially produce 20 million seeds a year. That could result in a lot of seedlings.

An article from the Plant Conservation Alliance describes the biology of the plant along with measures to control its growth. More detailed information about care of Paulownia is available at this website.

If you plan to remove your princess trees, you might consider these native alternatives:

Ilex opaca (American holly)

Cercis canadensis (eastern redbud)

Amelanchier canadensis (Canadian serviceberry)


More Non-Natives Questions

Distribution vs. Native Distribution in NPIN?
September 27, 2013 - I'm a Habitat Steward in Austin and conducting a native plant swap tomorrow, 9/28/13. I need to be able to tell people who come whether their plant is native or not. I want to use your smart phone ...
view the full question and answer

Winter care for non-native ice plant in Virginia
August 15, 2008 - I have an ice plant in my garden and it is doing very well. What would be the care for winter. Ground seldom freezes, temperatures mostly 20 but can get in single digit occasionally. Very little snow ...
view the full question and answer

Yellowing leaves in non-native Arbutus unedo in Washington
July 03, 2008 - I live in the Pacific Northwest and have planted 2 dwarf strawberry trees. I have been giving them lots of water. Their leaves are turning yellow. Am I watering them too much? Not enough?
view the full question and answer

Managing non-native invasive creeping yellow cress in Rio Medina TX
January 10, 2012 - Due to my lawn mower dying and waiting for the shop to fix it my yard got a bit overgrown. I was walking around the yard looking at the blooming wildflowers and have discovered that one of them is Ror...
view the full question and answer

Non-native Jacaranda interfering with concrete wall from Los Angeles
August 17, 2011 - We have been replanting the area surrounding our 2 story apt bldg and on one area, there is Jacaranda that started growing in an enclosed cement block wall area. The cemented walled in area which is ...
view the full question and answer

Support the Wildflower Center by Donating Online or Becoming a Member today.
© 2016 Lady Bird Johnson Wildflower Center