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Thursday - May 13, 2010

From: Lakeway, TX
Region: Southwest
Topic: Non-Natives
Title: Non-native Paulownia tree roots around pool in Austin
Answered by: Barbara Medford


We live in Lakeway (basically Austin) and planted a Paulownia tree in our back yard. It is growing well. However, since we planted it a couple of years ago we have put in an in-ground pool. During the two weeks it took them to chop out the hole we definitely received verification that our back yard is solid rock after about a foot of dirt. Now that the pool is in we are trying to ascertain if any of the trees behind it are too close and could cause damage with their roots. The tree I am speaking of is 11' from the wall of the pool. Can you tell us how close the Paulowia can safely be next to the walls of pool or home? We would rather be safe than sorry and have been unable to find anyone that knows enough about the roots of this tree to advise. Thank you for any help or referral you can provide.


Before we answer your question, let us tell you what we know about the tree. It is variously called "Royal Empress," "Royal paulownia" and "Princess Tree." It is called a lot of other things by people who either inherited this tree in their yards, bought and planted one, or had one planted by seedlings. However, this is a family website and we can't repeat those things. 

Begin by reading, from the Plant Conservation Alliance's Alien Plant Working Group Least Wanted : Royal Paulownia - Princess Tree - Royal Empress Tree - Paulownia tomentosa.

We would also like for you to read the comments on this Dave's Garden forum site on Paulownia tomentosa, in particular, the 7 negative comments.  Notice the comments about it showing up in disturbed ground, like where a swimming pool has been put in, and about the roots breaking up foundations, just from a seed that caught on the corner of that foundation and grew into a tree. Considering this tree is purported to grow 8 ft. a year, and that most trees have root system circumferences of 2 to 3 times the height of a tree, we would say your pool, sidewalks, house foundation and maybe the next-door neighbor's foundations are all at risk. If you planted it only a couple years ago, maybe it has not yet started seeding. If you let it live long enough to seed, not only will you be fighting a grove of these plants, but your pool will be a mess all the time. 

Our advice is to get rid of it while you still can. Roots will send up suckers trying to survive, and you will have to be after them all the time, and we just hope it has cast no seeds yet. Please, not in Austin, we are already having enough trouble with invasives.



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