Contact Us Host an Event 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 - 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

Plants for under Oak Trees in LA.
March 05, 2013 - What type of plants and grass can be planted under and around oak trees
view the full question and answer

Low, Easy Care Perennials for Lake Ontario Shore Planting
October 04, 2015 - I'm on Lake Ontario in New York. I have a lake bank slope, thatís about 1/8 mile long and about 40 feet high, and is on about a 40 degree angle. It is very hard to keep clear. The bank has just been ...
view the full question and answer

Looking for a native turf grass for the Houston area
July 25, 2013 - Looking for a native turf grass for the Houston area. In some of your 2012 responses, you stated that "The good news is that research into turf-type grasses native to the coastal region is in the pla...
view the full question and answer

Phytoremediation using Paspalum vaginatum
February 06, 2015 - Do you know of any on-going research using Paspalum vaginatum as the prime plant (monoculture) for use in phytoremediation. Utilizing this plant in Vegetated Swales, Spreader Swales, Grassy Swales,...
view the full question and answer

Plants for wet soils in North Carolina
October 03, 2009 - I'm looking for evergreen plants (shrubs or ground cover)that will tolerate wet conditions for the zone 8 area of North Carolina. The local garden centers here do not stock these types of plants, eve...
view the full question and answer

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