Host an Event Volunteer Join Tickets

Support the plant database you love!

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 - May 04, 2013

From: San Antonio, TX
Region: Southwest
Topic: Groundcovers, Shade Tolerant
Title: Groundcover for shade under oaks in San Antonio
Answered by: Nan Hampton

QUESTION:

I have been modifying my landscape to reduce grass and the need for frequent watering. Have turned half the backyard into native plants garden with hardscape and sitting areas. Have 2 mature Monterey oaks in middle of backyard providing lots of shade, with a large saga palm between them. Can you recommend a ground cover or low-growing plant which will grow in all that shade?

ANSWER:

The biggest problem growing something in the shade of your oaks is, well, all that shade.   Most plants prefer to grow in sun or partial shade.  There are some, however, that will grow quite happily in the shade or partial shade.  Also, there may be a problem growing plants under your oak tree, not just because it will be shady but because the oak tree has an allelopathic effect on some other plants.  Allelopathy is a situation where a plant releases a chemical that has an effect on another plant.  The effect may be beneficial or harmful, but the ones we hear about the most are those that are harmful to another plant.  One of best known of the allelopathic plants is the walnut tree (Juglans spp.).  It has a very strong effect on most plants attempting to grow beneath it.  Trees with a lesser allelopathic effect include oaks, hackberries and eucalyptus trees.  Red oaks, which in your area would be Quercus buckleyi (Texas red oak), are mentioned more often than other oak trees.  You can read more about allelopathy in this article, Allelopathic plants: nature's weedkillers.  That said, not all plants are susceptible to the oak's chemicals.  Some plants can grow under oaks.  I couldn't find a list of plants native to Texas that reportedly grow under oaks, but I have seen the following growing happily under oaks:

Carex blanda (Eastern woodland sedge) is evergreen.

Carex planostachys (Cedar sedge) is evergreen.

Carex texensis (Texas sedge) is evergreen.

Chasmanthium latifolium (Inland sea oats) is perennial and turns golden brown in the winter.  You can cut them back down to the new green rosettes forming in the early spring to show their vibrant new growth.  They are happy growing in the shade of oaks.  This grass grows 2 to 4 feet and is very attractive.

Calyptocarpus vialis (Straggler daisy) will probably remain evergreen in San Antonio and do just fine under oaks.

Geum canadense (White avens) is evergreen and can be mowed.

Packera obovata (Golden groundsel) will form an evergreen ground cover.

Salvia lyrata (Lyreleaf sage) makes an evergreen ground cover.

Paxistima myrsinites (Mountain lover)  Here are photos and more information from Southwest Colorado Wildflowers.

 

From the Image Gallery


Eastern woodland sedge
Carex blanda

Cedar sedge
Carex planostachys

Texas sedge
Carex texensis

Inland sea oats
Chasmanthium latifolium

Horseherb
Calyptocarpus vialis

Horseherb
Calyptocarpus vialis

White avens
Geum canadense

White avens
Geum canadense

Golden groundsel
Packera obovata

Golden groundsel
Packera obovata

Lyreleaf sage
Salvia lyrata

Oregon boxleaf
Paxistima myrsinites

More Groundcovers Questions

Vinca minor and St. Augustine grass
November 22, 2009 - Will St. Augustine grass choke out vinca minor?
view the full question and answer

Low-growing plants for a slope in the shade
July 08, 2013 - Hello, I'm looking for native plants to put in the shade (within the drip-line) of a well-established American Holly. The area gets deep shade; it is also on a very gentle north-exposure slope. We ...
view the full question and answer

Ground cover for New York sloped area
November 24, 2009 - I'm looking for native ground covers (vines?) for steep, heavy shale sloped areas as well as a ground cover in gently sloped area, preferably not higher than 6 inches. All that I've found is non-nat...
view the full question and answer

Replacing Weeds with Native Plants in Dallas Area
May 29, 2011 - I have a large oak tree in my front yard and lots and lots of miscellaneous weeds (clover, chickweed, stickers, etc.). I am wanting to grow grass in my front yard, that is shaded pretty much most of t...
view the full question and answer

Groundcover for Poconos in Pennsylvania
March 09, 2009 - Hi Mr. Smarty Plants, I am having a problem growing grass. I live in the Pocono mtns of Pa. my soil is not typical for this area. I have very sandy soil, probably poor quality. grass will not grow. I...
view the full question and answer

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