En EspaŅol

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?

Share

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
Can't find the answer in our existing FAQs, submit a question to Mr. Smarty Plants.
Need help with plant identification, visit the plant identification page.
 
rate this answer
1 rating

Saturday - December 22, 2012

From: Round Rock, TX
Region: Southwest
Topic: Water Gardens, Trees
Title: Cover oak roots with a pond from Round Rock TX
Answered by: Barbara Medford

QUESTION:

Hello! I have looked for this answer. We have 2 huge old beautiful live oaks. One is very close to the patio and house, and the other is about 20 feet of the house. Thus, part of their root systems are covered by the house. They were there first! Both are doing well. We are designing a pond in the yard. My question is whether it is safe to cover more live oak roots, about 20 feet out from the trunks. The pond will be lined, so I believe this will take some water away from the trees. The pond will not cover the entire areas, but will cover a big part of the yard starting just beyond one oak's canopy (about 20 feet from the trunk) and dipping under the other oak's canopy approximately 20 feet in and 20 feet in width. Do you think our pond plan is OK? Thanks!

ANSWER:

Which is more important? The pond or the oaks? We believe you are creating a large amount of impervious surface above those oak roots, just as if you were paving over the yard. As you say, the oaks were there first, and only you can decide if it is worth the risk.

An oak tree root system is extensive but shallow. The ground area at the outside edge of the canopy, referred to as the dripline, is especially important. The tree obtains most of its surface water here, and conducts an important exchange of air and other gases. Any change in the level of soil around an oak tree can have a negative impact. The most critical area lies within 6 to 10 feet of the trunk. No soil should be added or scraped away from that area. Construction activity is a great threat to trees. Do not allow any piling of materials, waste, etc. in the dripline area.

Paving should be kept out of the dripline and no closer than 15 feet from the tree trunk. If at all possible, use a porous paving material such as brick with sand joints, open bricks, bark, gravel, etc., which will allow some water penetration and gas exchange. Even with porous paving, the area around the trunk-at least a 10 foot radius-should be natural and uncovered

Water Gardening from How To Articles. From that article:

"Finding an ideal location for your pond should be your first consideration. It is possible to have a water garden in considerable (although not dense) shade, but leaves falling from nearby trees are a maintenance headache. Your largest selection of aquatic plants are those that grow in plenty of sun."

Previous Mr. Smarty Plants answer - Shade Trees Not Invasive to Foundations and Driveways

Previous Mr. Smarty Plants answer - Distance of oak tree to existing driveway in San Antonio

So, do we think your plan is okay? Sometimes when you can't find an answer to a question, it's because the answer is "no." There is absolutely no reason why you cannot do precisely as you have outlined. The trees might survive, but if they don't, you will need a Time Machine to fix it. You have asked our opinion. Since we live in dry, arid Texas, we would vote for the tree every time.

 

More Water Gardens Questions

Hungry turtles trample pond in Houston Texas
October 17, 2011 - I have a very large back yard pond (actually, a former swimming pool) that's home to a bullfrog, four Red-eared slider turtles, and scads of gambusia (little mosquito eating fish). I'd like to add n...
view the full question and answer

Winter tank pond care in Austin Texas
November 09, 2010 - Suggestions for winterizing a water garden in Austin Texas. Water contained in a 60 gallon aluminum horse tank. Garden contains papyrus, horsetail and water lily. There are no fish in the pond and no...
view the full question and answer

Plants for freestanding water in Oklahoma
July 28, 2013 - I have an overflowing gutter and the ground below becomes a muddy hole. I'd like to put a basin or pot in/or above the ground with a rain chain. Are there any plants--shrubs or otherwise that flouris...
view the full question and answer

Plants for wet soil in turtle enclosure in Virginia
September 03, 2010 - We recently installed a turtle pond in our backyard in Arlington, VA. We built an enclosure around the pond to protect the turtle from raccoons and herons, and left some open area for the turtle to g...
view the full question and answer

Pond plants that ducks will NOT eat
March 27, 2009 - What kind of pond plants are there that ducks will NOT eat?
view the full question and answer

Smarty Plants's Facebook profile Support the Wildflower Center by Donating Online or Becoming a Member today.

Mr. Smarty Plants wants you to be his Facebook friend. Click the Facebook icon to add yourself to Mr. Smarty Plants list of friends.
E-NEWSLETTER | BECOME A MEMBER | DONATE NOW | MEDIA | SITEMAP | STAFF
© 2015 Lady Bird Johnson Wildflower Center