The Dryland Garden

Echinocereus reichenbachii in Seattle June 2009

Yucca harrimaniae in Seattle August 2008

Sedum palmeri in Seattle December 2009

Tulipa turkestanica in Seattle March 2010

 Lewisia cotyledon in Seattle May 2010

Drylands are ecosystems with limited water, including scrublands, shrublands, grasslands, savannas, semi-deserts & true deserts.  A true desert garden is impossible in Seattle.  But you can give the impression of desert-like landscapes with carefully chosen plants, a very spare planting design, & plenty of rock & gravel.  This type of xeric garden is excellent for south or west-facing slopes, because it requires little or no irrigation.  If you’ve ever walked in a desert, you were probably surprised by the richness of the plant life.  There are some relatively barren deserts worldwide.  But the deserts of North America are filled with cactus, shrubs & small trees, perennial & annual wildflowers & grasses.  Below are images of natural drylands I have visited.  My ideas for the dryland garden are a synthesis of these landscapes & others I have seen.

 Joshua Tree National Park in California March 2009

Warm Springs Indian Reservation in Oregon September 1999

Frenchman Coulee in Washington June 2010

Cactus are nearly impossible to grow in Seattle.  I grow Echinocereus reichenbachii (Claret Cup Cactus) against the south side of a large stone, the only cactus that has worked for me.  Agave are somewhat less difficult.  I’ve tried at least a dozen, had success with Agave palmeri, Agave parryi var. huachucensis & Agave toumeyana var. bella. Yucca are similar to Agave & closely related.  Yucca filamentosa is widely grown in Seattle.  Native to the southeastern US, it tolerates dryness & moisture.  Western dryland Yucca that have grown well for me are Yucca harrimaniae, Yucca kanabensis, Yucca glauca, Yucca neomexicana & Yucca schottii.  I was amazed to find that Yucca whipplei, which grows in the very dry mountains near Los Angeles, grew to 4 feet  from a mere 6 inches in just 4 years.  It is both striking & alarming with its needle-tipped, sword-like leaves.  Plant Agave & Yucca well away from paths.  Agave, cactus & dryland Yucca should be grown in a raised area of gravelly & rocky soil.  Other successful succulent plants are Lewisia cotyledon & many Sedum.

I saw scrub oak growing in the Mojave Desert.  Scrub oaks include Quercus berberidifolia, Quercus john-tuckeri & Quercus vaccinifolia.  Shrubby pines such as Pinus edulis also grow in drylands.  A well-pruned Swiss Mountain Pine (Pinus mugo) will have a similar appearance.  Other dryland shrubs include manzanita & juniper.  You must to prune juniper, manzanita, oak & pine to give them a dryland appearance. To mimic sagebrush, use shrubs with gray foliage such as Brachyglottis munroi, Helichrysum splendidum & Santolina chamaecyparissus.  Rosa glauca & Rosa sericea var. pteracantha (with tall, thorny canes) give the impression of desert plants, especially in winter:

Wildflowers & grasses are always found in western drylands. Festuca idahoensis is a common grass from drylands of the Pacific Northwest & California.  It also grows west of the Cascade Mountains.  Try grasses with blue foliage such as Festuca ovina ‘Elijah Blue’ & Helictotrichon sempervirens, or with bronze foliage such as Carex comans ‘Bronze’ & Carex tenuiculmis ‘Cappucino’ .  For flowers use Achillea, Anthemis tinctoria, Erigeron, Penstemon x mexicali & Zauschneria californica.  Bulbs native to the western US are Calochortus & Triteleia.  Certain species tulips will also fit into this garden, although they are wildflowers from central Asian drylands.

Dry Garden Plant List

Succulents
Agave palmeri, Agave parryi var. huachucensis, Agave toumeyana var. bella
Echinocereus reichenbachii (Claret Cup Cactus)
Hesperaloe parviflora (Red Yucca)
Lewisia tweedyi, Lewisia cotyledon
Nolina nelsonii, Nolina parryi
Sedum divergens, Sedum oreganum, Sedum obtusatum, Sedum oregonense, Sedum palmeri, Sedum spathulifolium
Yucca filamentosa, Yucca harrimaniae (aka Yucca nana) Yucca kanabensis, Yucca neomexicana, Yucca glauca, Yucca schottii, Yucca whipplei

Shrubs & Small Trees
Arctostaphylos columbiana (Hairy Manzanita) Arctostaphylos bakeri, Arctostaphylos densiflora (Vine Hill Manzanita)
Brachyglottis monroi
Calluna vulgaris ‘Kerstin’, Calluna vulgaris ‘Silver Knight’
Eriogonum umbellatum (Sulfur Buckwheat)
Helichrysum italicum, Helichrysum splendidum, Helichrysum tianshanicum
Juniperus californica, Juniperus squamata ‘Blue Star’, Juniperus squamata ‘Loderi’
Lithocarpus densiflorus var. echinoides (Dwarf Tanbark Oak)
Mahonia fremontii (Desert Holly) Mahonia pinnata
Penstemon pinifolius (Pineleaf Beardtongue)
Pinus aristata (Bristlecone Pine) Pinus edulis (Pinyon Pine) Pinus monophylla (Singleleaf Pinyon) Pinus mugo (Swiss Mountain Pine) Pinus quadrifolia (Parry Pinyon)
Quercus berberidifolia (Scrub Oak) Quercus gambelii (Gambel Oak) Quercus john-tuckeri (John Tucker Oak) Quercus vaccinifolia (Huckleberry Oak)
Rosa glauca, Rosa sericea var. pteracantha
Santolina chamaecyparissus (Lavender Cotton)

Perennials & Grasses
Achillea ageratifolia, Achillea clavennae, Achillea kellereri, Achillea serbica, Achillea tomentosa (Yarrow)
Anthemis tinctoria (Marguerite Daisy)
Briza media (Rattlesnake Grass)
Calochortus superbus, Calochortus venustus (Mariposa Lilies)
Carex comans ‘Bronze’ (New Zealand Sedge) Carex tenuiculmis ‘Cappuccino’
Coreopsis verticillata (Tickseed)
Deschampsia flexuosa (Crinkled Hairgrass)
Erigeron glaucus (Beach Aster) Erigeron karvinskianus (Santa Barbara Daisy) Erigeron lineraris (Desert Yellow Fleabane)
Eryngium variifolium (Moroccan Sea Holly) Eryngium yuccifolium (Rattlesnake Master)
Eschscholzia californica (California Poppy)
Festuca idahoensis, Festuca ovina ‘Elijah Blue’ (Fescues)
Helictotrichon sempervirens (Blue Oat Grass)
Pennisetum alopecuroides ‘Hameln’ (Fountain Grass)
Penstemon x mexicali (Beardtongue)
Triteleia laxa ‘Queen Fabiolia’ (aka Brodiaea ‘Queen Fabiola’)
Tulipa dasystemon, Tulipa saxatilis, Tulipa turkestanica (Species Tulips)
Zauschneria californica (California Fuchsia) Zauschneria latifolia

Groundcovers & Trailers
Arctostaphylos x media, Arctostaphylos nevadensis (Pinemat Manzanita) Arctostaphylos nummularia
Ceanothus griseus var. horizontalis (Carmel Creeper)

Cerastium tomentosum (Snow-in-Summer) 
Hirpicium armerioides (Mat Daisy)
Juniperus communis ‘Green Carpet’, Juniperus conferta (Shore Juniper)

  

Plan for a Dryland Garden
This garden must be very well-drained.  It is best on south & west-facing slopes, in full sun.  The center area can be a raised bed enclosed with a stone wall.

Shrubs & Small Trees

AC = Arctostaphylos columbiana (Hairy Manzanita)

AD = Arctostaphylos densiflora (Vine Hill Manzanita) 
HEL = Helichrysum italicum, Helichrysum splendidum, or Helichrysum tianshanicum

MAH = Mahonia fremontii (Desert Holly) or Mahonia pinnata

PINE = Pinus aristata (Bristlecone Pine) Pinus edulis (Pinyon Pine) Pinus monophylla (Singleleaf Pinyon) or Pinus quadrifolia (Parry Pinyon) or use Quercus berberidifolia (Scrub Oak) Quercus gambelii (Gambel Oak) Quercus john-tuckeri (John Tucker Oak) Quercus vaccinifolia (Huckleberry Oak)

ROSA = Rosa glauca, or Rosa sericea var. pteracantha

SAN = Santolina chamaecyparissus (Lavender Cotton)

Perennials & Grass
ACH = Achillea tomentosa (Yarrow)

CAR = Carex comans ‘Bronze’ (New Zealand Sedge) or Carex tenuiculmis ‘Cappuccino’

ERI = Erigeron glaucus (Beach Aster)

ERY = Eryngium variifolium (Moroccan Sea Holly) Eryngium yuccifolium (Rattlesnake Master)

TUL = Tulipa dasystemon, Tulipa saxatilis, or Tulipa turkestanica (Species Tulips)

ZAU = Zauschneria californica (California Fuchsia)

Groundcover

JUN = Juniperus communis ‘Green Carpet’, or Juniperus conferta (Shore Juniper)

Mulch with crushed granite, gravel, lava rock, or other crushed rock.  Place smaller plants such as Achillea ageratifolia, Achillea clavennae, Achillea kellereri, Achillea serbica, Agave toumeyana var. bella, Cerastium tomentosum, Erigeron lineraris, Hirpicium armerioides, Lewisia tweedyi, Lewisia cotyledon, Sedum divergens, Sedum oreganum, Sedum obtusatum, Sedum oregonense, Sedum palmeri, Sedum spathulifolium, Yucca harrimaniae, Yucca nana &/or stones in open spaces as desired.  Agave & Yucca should be grown in a raised area of gravelly & rocky soil.

You can get Achillea ageratifolia, Achillea kellereri, Achillea serbica, Erigeron lineraris, Hirpicium armerioides, Mahonia fremontii, Pinus edulis, Yucca harrimaniae & Yucca nana by mail from High Country Gardens.  Pinus aristata, Quercus berberidifolia & Quercus gambelii are available from Forest Farm (other pines & oaks have been available in the past, may be in the future).