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Monday - February 09, 2015

From: Austin, TX
Region: Southwest
Topic: Plant Lists, Septic Systems
Title: Septic Field Recommendations for SW Austin
Answered by: Larry Larson

QUESTION:

What would be good native plants to vegetate septic drip fields in both sun and shade in Southwest Austin. The regulations want plants that are evergreen and shallow rooted.

ANSWER:

The standard recommendation for plantings over septic fields is shallow rooted herbaceous plants.  I found two references on the web that echoed that direction but also supplemented that with plant lists.  Landscaping Over Septic Drain Fields” is a publication of Clemson University and “Planting on Your Septic Drain Field” is published by the Virginia Cooperative Extension: 

  At the same time, the Wildflower Center always recommends plants from the recommended species for the area.  Southwest Austin is part of the Edwards Plateau ecoregion.  This link is to the list of recommended species for the area. 

  Mr. Smarty Plants strategy from here is to take these lists and look for overlaps or similar species. The following is a Texas version of the Clemson list.   As there are quite a few of overlaps I’ll only list a half dozen or so for each category.  As you mentioned that the regulations (Homeowners Assn.??) require evergreens, I’ll take note of those especially.

Ornamental Grasses:
Andropogon gerardii (Big bluestem)
Bouteloua curtipendula (Sideoats grama)Bouteloua dactyloides (Buffalograss)
Chasmanthium latifolium (Inland sea oats)
Eragrostis intermedia (Plains lovegrass)
Muhlenbergia lindheimeri (Lindheimer's muhly)

FORBS  [Wildflowers]
Amblyolepis setigera (Huisache daisy)
Callirhoe involucrata (Winecup)   [Evergreen]
Castilleja purpurea (Prairie paintbrush)
Coreopsis basalis (Goldenmane tickseed)
Gaillardia pulchella (Firewheel)
Glandularia canadensis (Rose vervain)   [Evergreen}
Melampodium leucanthum (Blackfoot daisy)
Dalea frutescens (Black dalea) 

Perennials:
Amsonia ciliata (Fringed bluestar)
Lobelia cardinalis (Cardinal flower)
Phlox drummondii (Annual phlox)
Phlox roemeriana (Goldeneye phlox)
Salvia azurea (Pitcher sage)
Tradescantia gigantea (Giant spiderwort)

For Sunny, Dry Conditions:
Achillea millefolium (Common yarrow)
Andropogon spp. - Bluestem Grass
Asclepias texana (Texas milkweed)
Coreopsis basalis (Goldenmane tickseed)
Euphorbia cyathophora (Wild poinsettia)
Gaillardia pulchella (Firewheel)
Opuntia macrorhiza (Common prickly-pear)   [Evergreen]
Rudbeckia hirta (Black-eyed susan)
Ruellia nudiflora (Violet ruellia)
Salvia azurea (Pitcher sage)      [Evergreen]

  Since only a few Evergreens showed up – You can search the Recommended Species directly for Evergreens.  That gave 42 candidates that grow on the Edwards Plateau.  Several good candidates from this list are:
Dichondra argentea (Silver ponyfoot)
Chrysactinia mexicana (Damianita)
Dasylirion texanum (Texas sotol)

  Have you considered Yuccas or Cactus’ ?   These are listed as Evergreens and generally have shallow root systems:
Hesperaloe parviflora (Red yucca)
Fouquieria splendens (Ocotillo)
Nolina lindheimeriana (Devil's shoestring)
Opuntia engelmannii var. engelmannii (Cactus apple)
Yucca constricta (Buckley yucca)
Yucca rupicola (Twistleaf yucca)
Yucca treculeana (Spanish dagger)

 

From the Image Gallery


Big bluestem
Andropogon gerardii

Inland sea oats
Chasmanthium latifolium

Lindheimer's muhly
Muhlenbergia lindheimeri

Winecup
Callirhoe involucrata

Rose vervain
Glandularia canadensis

Cardinal flower
Lobelia cardinalis

Pitcher sage
Salvia azurea

Texas sotol
Dasylirion texanum

Damianita
Chrysactinia mexicana

Red yucca
Hesperaloe parviflora

Devil's shoestring
Nolina lindheimeriana

Twistleaf yucca
Yucca rupicola

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