Rent Shop Volunteer Join

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

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
Not Yet Rated

Saturday - January 30, 2010

From: Clover, SC
Region: Southeast
Topic: Trees
Title: What plants to put under an oak tree in Clover SC
Answered by: Barbara Medford

QUESTION:

I have a 70 year old oak tree in my backyard and have tried to grow grass out from it with no success. I'd like to just plant some shrubs and make it a natural area now, but need advice on what I can plant near the oak, not directly under it. The area where I want to create a garden is about 10-12 feet from the oak. I've planted flowers away from the oak in the past, but nothing has done well. Any suggestions on shrubs or flowers that I would do well about 10 ft away from the oak? Also, would it be better to create a large raised bed and create a garden area that way?

ANSWER:

An oak tree that old is a valuable landscape asset, so your first question should probably be: "What will not harm the tree?" Oak trees do not like competition. Their heavy shade in summer, and the year-round presence of the root system are disadvantages for plants beneath the oak. Furthermore, the mature oak is known to have the quality of allelopathy, which means they emit substances that will inhibit the growth of plants beneath them; these substances can come from roots, twigs, or leaves. You say you plan to plant 10 to 12 feet from the oak, we assume that is from the trunk. A tree that old likely has a pretty impressive canopy, and the roots can extend out up to three times the circumference of that canopy.

Next, your idea of making a raised bed would possibly permit you to grow some plants, but it would not be good for the oak. These far-reaching roots we described reside mostly in the upper 12 inches of the soil. That characteristic is to ensure the roots have easy access to moisture, nutrients and oxygen. Piling soil up on those roots might not damage the tree right away, but in the long run it could begin a die-back of the most affected areas, eventually becoming an unattractive liability. If you dig holes for shrubs in the ground level, without raising the bed, you will both be destroying roots of the tree and putting roots of the shrubs in competition with the roots of the tree, whch is advantageous to neither.

We don't like to sound so negative, but we also would hate for you to waste time and resources putting in plants that will not thrive and possibly damaging your tree, as well, in the process. One possibility might be to put down a good quality shredded bark mulch beneath the tree, and perhaps ring that mulch with shrub beds having the same mulch in them. They would blend together nicely and look natural. With that in mind, we are going to recommend some shrubs native to South Carolina that will tolerate sun or part shade. We tried to choose some that are considered "understory" plants; i.e., they should do pretty well at coping with interference from trees. Follow each link to the page on that plant to learn other characteristics and growing conditions. 

Shade or Part Sun Shrubs for Cover SC:

Callicarpa americana (American beautyberry) - 3 to 5 ft. tall, deciduous, blooms white, pink May to July, part shade

Comptonia peregrina (sweet fern) - 2 to 4 ft., blooms white, green May to August, part shade

Hydrangea arborescens (wild hydrangea) - 3 to 6 ft., deciduous, blooms white, green June to August, part shade

Hypericum prolificum (shrubby St. Johnswort) - to 3 ft., deciduous, blooms yellow June to August, part shade or shade

Symphoricarpos orbiculatus (coralberry) - 4 ft., deciduous, blooms white, green April to July, part shade or shade

From our Native Plant Image Gallery:


Callicarpa americana

Comptonia peregrina

Hydrangea arborescens

Hypericum prolificum

Symphoricarpos orbiculatus

 

 

 

More Trees Questions

Pruning an oak tree in Missouri in February
February 09, 2009 - Can I prune an oak tree in Missouri in February?
view the full question and answer

Spots on persimmon tree leaves from Dripping Springs TX
July 10, 2013 - We are in rural Hays County Texas off Hamilton Pool Rd Texas. Large persimmon trees are turning yellow, blackish spots on underside of leaves. What do we do?
view the full question and answer

How Do Persimmons Breed - Starkville, MS
August 14, 2012 - Thank you for your earlier response about the genders of native persimmon trees. We have two, a much larger one that has borne fruit for years and years and a smaller one that I'd just assumed was m...
view the full question and answer

Shrubs and trees over septic tank in Killen AL
May 20, 2013 - Our church has 5year old blue rug juniper, a crape myrtle and two shrubs I can't identify planted over the septic tank which is surrounded with concrete and asphalt. I am afraid these will cause a pr...
view the full question and answer

Tree roots breaking surface in Allen, TX
March 09, 2009 - I live in Northern Texas, near Dallas. My questions concerns a tree in my front yard that now has roots that break the surface of the soil and grass. I would like to cover the roots. Should I cover...
view the full question and answer

Support the Wildflower Center by Donating Online or Becoming a Member today.