Plants for Heavy Soils

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Compiled by the Theodore Payne Foundation for Wildflowers and Native Plants, Inc.

 

"Heavy" soils are distinguished from "light" soils by the size of their component particles. Heavy soils like clay or silt retain more moisture than those with larger particles, such as sand and decomposed granite. Because they are so dense, heavy soils have fewer air spaces for roots to 'breathe.' Most native plants prefer good drainage, which means that they will not tolerate constantly, moist, dense soil. Luckily, many native plants are more sensitive to the amount of water in the soil than they are to the type of soil in which they are planted. The best regime for native plants in heavy soil is therefore to water deeply but infrequently, soaking the soil completely and then allowing it to dry out. (Keep in mind that flat areas drain more slowly than hilly areas and that the top of a slope dries out more quickly than the bottom.) To prevent the proliferation of destructive microorganisms that cause root rot, never allow water to stand around the base of a plant.

 
KEYS TO FLOWER COLOR: B  Blue V  Violet/Purple
R  Red 0  Orange
G  Green W  White
P   Pink Y  Yellow
 

GROUNDCOVERS:

  • Achlllea mlllefolium, Yarrow P/R/W
  • Adenostoma fasciculatum, prostrate form Chamise W
  • Arctostaphylos edmundsii and cultivars, Manzanita W/P
  • Arctostaphylos uva-ursi W/P
  • Baccharis pilularis Twin Peaks' or 'Pigeon Point', Prostrate Coyote Brush W
  • Ceanothus griseus horizontalis, Carmel Creeper B/V
  • Ceanothus griseus horizontalis 'Yankee Point' B/V
  • Ceanothus maritimus, Maritime Ceanothus B/V

GRASSES:

  •  Bouteloua spp., Elymus spp., Festuca spp., Muhlenbergia spp., Sporobolus alroldes, Stipa spp., etc.

RUSHES:

  • Juncus spp.

SEDGES:

  • Carex spp.

PERENNIALS & ANNUALS:

  • Eschscholzia californica, California Poppy 0
  • Heuchera spp. and hybrids, Alum-Root/Coral Bells P/R/W
  • Iris spp. and hybrids B/V/W/Y
  • Iva hayesiana, Hayes' Iva (flowers insignificant)
  • Mentha arvensis, Field Mint W/V
  • Monardella spp.. Coyote Mint V/W
  • Oenothera hookeri, Hooker's Evening Primrose Y
  • Ribes viburnifolium, Catalina Currant R
  • Satureja spp.. Savory 0/W

 

SHRUBS :

  • Arctostaphylos densiflora'Howard McMinn' and Arctostaphylos densiflora 'Harmony' P/W
  • Artemlsia californica, Coastal Sagebrush
  • Atriplex spp., Saltbush
  • Baccharis spp.. Coyote Brush W
  • Berberis aquifollum, Oregon Grape Y; B. Nevinii, Nevin's Barberry Y; Berberis repens, Creeping Barberry Y
  • Ceanothus griseus, Carmel Ceanothus and Ceanothus cultivars 'Concha', 'Frosty Blue', and 'Julia Phelps' B/V
  • Cercocarpus betuloides, Mountain-Mahogany W
  • Cercocarpus ledifolius,. Desert Mountain-Mahogany W
  • Encelia callfornica, California Bush Sunflower Y
  • Eriogonum crocatum, Conejo Buckwheat Y
  • Eriogonum fasciculatum, Buckwheat W
  • Eriogonum giganteum, St. Catherine's Lace W
  • Galvezia juncea, Baja Bush Snapdragon R and G. speclosa. Island Bush Snapdragon R
  • Haplopappus squarrosus, Coast Goldenbush Y
  • Lavatera assurgentiflora, Tree Mallow P/V and Lavatera 'Purlsima', Hybrid Bush Mallow P/V
  • Lonlcera involucrata, Twinberry R/Y and L. subspicata, Chaparral Honeysuckle W
  • Malosma laurina, Laurel Sumac
  • Myrica callfornica, California Wax Myrtle
  • Rhus integrlfolia, Lemonade Berry; Rhus ovata, Sugar Bush P
  • Ribes aureum, Golden Currant Y
  • Rosa callfornica, California Wild Rose P
  • Salvia spp.. Sages B/P/R/V/W

TREES:

  • Acer macrophyllum, Bigleaf Maple
  • AInus rhombifblia, White Alder
  • Cercis occidentalls, Western Redbud P
  • Calocedrus decurrens, Incense Cedar
  • Chilopsis Iinearis, Desert Willow P/W
  • Cupressus forbesli, Tecate Cypress and C. sargentii, Sargent's Cypress
  • Fraxinus dipetala, Flowering Ash and F. velutina, Arizona Ash
  • Juglans callfornica, S. California Black Walnut and J. hindsii, N. California Black Walnut
  • Pinus attenuata, Knobcone Pine; P. coulteri, Coulter Pine; P. sabilniana, Gray Pine; P. torreyana, Torrey Pine
  • Platanus racemosa, Western Sycamore
  •  Populus fremontii, Fremont Cottonwood
  • Prunus lyonii, California Cherry W
  • Quercus agrifolia, Coast Live Oak; Q. chrysolepis, Canyon Live Oak; Q. engelmannii, Engelmann Oak
  • Sambucus mexicana, Elderberry W/Y

Plants that may prove difficult in heavy soils: Arctostaphylos spp. (Manzanita) other than those listed above, especially sand dune species. Astragalus spp. (Locoweed), Coreopsis gigantea (Giant Coreopsis), Dendromecon spp. (Bush Poppy), Eriophyllum spp. (Golden Yarrow), Fremontodendron spp. (Flannel Bush), Lupinus spp. (Lupine), Penstemon spp. (Penstemon), Trichostema lanatum, Woolly Blue-Curls; and various alpine plants and/or those that dwell on rocky slopes