Ask Mr. Smarty Plants

The first thing we need to do is figure out which plant you intend to move. When I went to our Native Plant Database and typed in "lily of the valley". This is the list of plants that I came up with.

American lily of the valley Convallaria majuscula (American lily of the valley)       map

False lily of the valley Maianthemum dilatatum (False lily of the valley)        map

Feathery false lily of the valley Maianthemum racemosum (Feathery false lily of the valley)     map

Feathery false lily of the valley Maianthemum racemosum ssp. racemosum (Feathery false lily of the valley)    map

Starry false lily of the valley Maianthemum stellatum (Starry false lily of the valley)      map

Threeleaf false lily of the valley Maianthemum trifolium (Threeleaf false lily of the valley)    map

Clicking on the scientific name of each of the plants will bring up its NPIN page which will allow you to see if any of the plants look like yours, and also learn its growth requirements. Clicking on the word “map” following each Scientific Name will bring up the USDA Plant Profile for the plant which includes a distribution map that indicates where the plant occurs naturally.

We can plot occurrence on this matrix
                                                                                           in TX      in MD      
Maianthemum racemosum (Feathery false lily of the valley)      yes         yes

Maianthemum stellatum (Starry false lily of the valley)             close       yes

Maianthemum racemosum ssp. racemosum (Feathery false lily of the valley)                                                                                                                     close       yes     

Maianthemum dilatatum (False lily of the valley)                       no          no

Maianthemum trifolium (Threeleaf false lily of the valley)           no          close  

Convallaria majuscula (American lily of the valley)                     close       close 

From the matrix we can see that Maianthemum racemosum (Feathery false lily of the valley) occurs in both MD and TX, but only in far west Texas. Maianthemum stellatum (Starry false lily of the valley) and Maianthemum racemosum ssp. racemosum (Feathery false lily of the valley) occur in MD and states adjoining Texas. SInce Maianthemum racemosum ssp. racemosum occurs in Louisiana, it might be a candidate for growing in Harris County. However, growing plants outside their native range is counter to the mission of the Lady Bird Johnson Wildflower Center.  And there are very good reasons for discouraging the importation of exotic species; weed, pest, and disease issues probably top the list.  So in regard to your question about approval, the short answer is no.