Ask Mr. Smarty Plants

The Lady Bird Johnson Wildflower Center is committed to encouraging the use of native flora, so our suggestions work from that palette of options.

You may have two issues here. Pecan trees are in the Juglandaceae family -  walnuts, butternuts, pecans and hickories. They practice a defense mechanism called allelopathy in which they release a chemical which retards the growth of other plants under them. In this case, it is a chemical called Juglone, found chiefly in buds, hulls and roots, which acts as an inhibitor. Black walnut has the highest concentration of Juglone but pecans can exhibit some of the same inhibitory behavior. Grasses are not notably affected by this chemical, but many other species are. This previous answer from Mr. Smarty Plants, although referring to a black walnut tree, gives you some excellent links to more information, as does this one on pecans in Dallas, TX.

Shade is the other factor which limits your options. Only some grasses are adapted to shade, and their growth patterns tend to have more of a woodland than a turf grass appearance. I have listed some grasses that are native to Tennessee and shade-tolerant. I also suggested a few ferns.

Other alternatives might be to use a native groundcover, a mix of native plants, or even just a layer of mulch as groundcover. The site below has a list of native plants particular to West Tennessee compiled by the Tennessee Exotic Pest Plant Council. Scroll to the bottom to see a suggested grouping of native plants for a shady spot. 

If you would like to research other options, go to our Native Plant Database, and use the Combination Search option. 

Carex blanda (eastern woodland sedge)

Carex crinita (fringed sedge) - pictures

Elymus hystrix var. hystrix (eastern bottlebrush grass)

Chasmanthium latifolium (Inland sea oats)

Elymus virginicus (Virginia wildrye)

Sorghastrum nutans (Indiangrass)

Muhlenbergia schreberi (nimblewill)

A little more about nimblewill, this grass can be a spreader; see this Wikipedia website Nimblewill.

Athyrium filix-femina (common ladyfern)

Adiantum pedatum (northern maidenhair)

Phegopteris hexagonoptera (broad beechfern)

Polystichum acrostichoides (Christmas fern)

Carex blanda

Elymus hystrix var. hystrix

Chasmanthium latifolium

Elymus virginicus

Sorghastrum nutans

Muhlenbergia schreberi

Athyrium filix-femina

Adiantum pedatum

Phegopteris hexagonoptera

Polystichum acrostichoides