Watch List: non-native species in Texas potentially ranked as F1  

 

      Many of the non-native species in Texas are known from relatively few populations.  Among these are a significant number that have been recently recorded for the state and that are known to be both invasive and ecologically destructive in other regions of the United States or other parts of the world.  These features characterize the species included on the “Watch List” –– the ones with high potential to rapidly become destructive in Texas.  A number of additional F3 species, especially the woody ones, and some of those ranked as F4 (“status unknown”) probably belong on the Watch List. 

 

      The Watch List account perhaps is the most significant part of the overview of Texas non-native native plants provided here.  The F1 species and many of the F2s are well-known invaders and already so widespread that it is unlikely that they can be eradicated or even controlled except by sustained efforts on local levels.  In a summary of efforts toward control of Giant Salvinia in Texas, it’s noted that “The only positive control discovered after 10 years of trial and error is the containment and removal of all plants immediately after detection” (Howard Elder, 2009, TIPPC Conference Abstract).  

 

      Research toward the possibility of biological control will be ongoing.  Further, there probably is little hope even of eradicating many of the Watch List species  –– a number of the woody species are widely cultivated, providing abundant seed sources close to natural areas, and it is unlikely that plants will be removed from the cultivated landscape.  Some measure of control might be gained by limiting further planting. 

 

      From among the Watch List species, a subset is indicated here as a “Super Watch List” (as marked with *asterisks below) –– those species that perhaps can be removed from the Texas landscape before they become impossible to control.  Close attention should go to these.  All of the F2 aquatics are included because of their potential for rapid dispersal and growth.  

 

from F1-HERBACEOUS

 

*Solanum viarum                          -- attempt to eradicate (but becoming locally abundant)

 

from F2-WOODY: 

 

*Hypericum perforatum               -- attempt to eradicate

*Pueraria montana var. lobata      -- attempt to eradicate

Pyrus calleryana                            -- widely cultivated, probably here to stay and increase

Vitex agnus-castus                                    -- widely cultivated, probably here to stay and increase

 

from F3-WOODY:

 

*Ardisia crenata                            -- attempt to eradicate

*Casuarina equisetifolia               -- attempt to eradicate

*Cinnamomum camphora                         -- attempt to eradicate (but commonly cultivated)

*Cortaderia selloana                     -- attempt to eradicate (but commonly cultivated)

*Elaeagnus angustifolia                -- attempt to eradicate

*Leucaena leucocephala               -- attempt to eradicate

*Lonicera maackii                                    -- attempt to eradicate (but becoming locally abundant)

*Macfadyena unguis-cati              -- attempt to eradicate

Photinia serratifolia                       -- widely cultivated, probably here to stay and increase

Pistacia chinensis                          -- widely cultivated, probably here to stay and increase

* Pyracantha koidzumii                 -- attempt to eradicate

Schinus molle                                -- widely cultivated, probably here to stay and increase

*Schinus terebinthifolius                          -- attempt to eradicate

Ulmus parvifolia                                        -- widely cultivated, probably here to stay and increase

 

from F2-HERBACEOUS:

 

Carduus tenuiflorus                      -- already abundant, at least locally, probably here to stay and increase

Cirsium vulgare                            -- already abundant, at least locally, probably here to stay and increase

*Clematis terniflora                      -- attempt to eradicate (but becoming locally abundant)

*Gibasis pellucida                                     -- attempt to eradicate

*Lespedeza cuneata                     -- attempt to eradicate (but becoming locally abundant)

Lolium (Festuca) arundinaceum    -- already abundant, at least locally, probably here to stay and increase

Perilla frutescens                                      -- already abundant, at least locally, probably here to stay and increase

Polygonum arenastrum                 -- already abundant, at least locally, probably here to stay and increase

Polygonum persicaria                   -- already abundant, at least locally, probably here to stay and increase

Stachys floridana                           -- already abundant, at least locally, probably here to stay and increase

Torilis arvensis                             -- already abundant, at least locally, probably here to stay and increase

Verbena brasiliensis                     -- already abundant, at least locally, probably here to stay and increase

 

from F3-HERBACEOUS:

 

*Carduus acanthoides                  -- attempt to eradicate

*Cayratia japonica                         -- attempt to eradicate

*Cryptostegia grandiflora                         -- attempt to eradicate

*Cuscuta japonica                                     -- attempt to eradicate

*Elymus repens                            -- attempt to eradicate

*Imperata cylindrica                     -- attempt to eradicate

*Lespedeza bicolor                       -- attempt to eradicate

*Lotus corniculatus                      -- attempt to eradicate

*Lythrum salicaria                        -- attempt to eradicate

*Microstegium vimineum                        -- attempt to eradicate

 

from F4-HERBACEOUS:

 

*Acroptilon repens                                   -- attempt to eradicate

*Dioscorea bulbifera                     -- attempt to eradicate  

 

from F2-AQUATIC:   

 

*Ceratopteris thalictroides           -- attempt to control and eradicate

*Colocasia esculenta                    -- attempt to control and eradicate

*Cryptocoryne beckettii               -- attempt to control and eradicate

*Egeria densa                               -- attempt to control and eradicate

*Hydrocleys nymphoides                          -- attempt to control and eradicate

*Hygrophila polysperma               -- attempt to control and eradicate (but becoming locally abundant)

*Landoltia punctata                       -- attempt to control and eradicate

*Limnophila sessiliflora                -- attempt to control and eradicate

*Ludwigia grandiflora subsp. grandiflora -- attempt to control and eradicate

*Ludwigia grandiflora subsp. hexapetala  -- attempt to control and eradicate

*Nomaphila stricta                        -- attempt to control and eradicate

*Nymphoides indica                      -- attempt to control and eradicate

*Nymphoides peltata                    -- attempt to control and eradicate

*Ottelia alismoides                       -- attempt to control and eradicate

*Potamogeton crispus                  -- attempt to control and eradicate

*Salvinia minima                           -- attempt to control and eradicate

*Xanthosoma sagittifolium            -- attempt to control and eradicate

 

 

Potential and expanding new arrivals with global warming

in south and coastal Texas:

 (fide Tom Patterson, South Texas College, Rio Grande City)

 

Caesalpina bonduc

Canavalia rosea

Cassytha filiformis

Conocarpus erectus

Laguncularia racemosa

Rhizophora mangle

Scaveola plumieri

 

---------------------------

Last update: 18 Oct 2009