X-, XX-, and XXX-Rated Plants

Nothing risqué going on here‹the ³X² stands for Xeriscape� low-water
gardening. Garden Centers of Colorado recently began rating ornamental
plants according to their typical water use rates: X = around 1" of
water per week (³thrives in slightly dry conditions²), XX = around 0.5"
of water per week (³thrives in dry conditions²), and XXX = around 0.5"
or less of water every two weeks (³thrives in very dry conditions²).
Here are the water use ratings of annuals and perennials listed on the
GCC web site http://www.xratedgardening.com.

Annuals
XXX-rated: Centaurea cyanus (cornflower), Eschschozia california
(California poppy), Portulaca grandiflora (rose moss), Salvia greggii
(autumn sage), Verbena bonariensis (purple top), Zinnia angustifolia
(star zinnia)
XX-rated: Catharanthus roseus (Madagascar periwinkle), Cleome
hassleriana (spider flower), Coreopsis tinctoria (coreopsis), Cosmos
bipinnatus (cosmos), Diascia barberae (twinspur), Gazania rigens
(treasure flower), Gomphrena globosa (globe amaranth); Ipomoea batatas
(sweet potato vine), Lantana hybrids (lantanas), Limonium sinuatum
(statice), Melampodium leucanthum (black foot daisy), Mirabilis jalapa
(four o¹clock), Nierembergia hippomanica (cup flower), Pennisetum
setaceum (fountain grass), Petunia hybrids (petunias), Rudbeckia hirta
(black-eyed Susan), Salvia farinacea (mealycup sage, Victoria types),
Sanvitalia procumbens (creeping zinnia), Scaevola aemula (fan flower),
Senecio cineraria (dusty miller), Tagetes species (marigolds),
Thymophylla tenuiloba (Dahlberg daisy), Tithonia rotundifolia (Mexican
sunflower), Verbena hybrids (trailing verbenas)
X-rated: Argyranthemum species (marguerite daisies), Brachycome
iberidifolia (Swan River daisy), Celosia plumose (cockscomb), Dianthus
species (pinks), Heliotrope species (heliotropes), Osteospermum species
(African daisies), Sutera cordata (bacopa), Tropaeolum majus
(nasturtium), Viola species (violas), Viola € wittrockiana (pansy),
Zinnia hybrids (zinnias)

Perennials
XXX-rated: Anacyclis pyrethrum var. depressus (Mt. Atlas daisy),
Antennaria species (pussy-toes), Artemisia frigida (fringed sage),
Asclepias tuberosa (butterfly weed), Berlandiera lyrata (chocolate
flower), Callirhoë involucrata (poppy mallow), Calylophus serrulaus
(sundrops), Centranthus ruber (Jupiter¹s beard), Echinops ritro (globe
thistle), Eriogonum species (sulfur flowers), Eryngium amethystinum (sea
holly), Euphorbia polychroma (cushion spurge), Gaillardia plicatus
(blanket flower), Gaura lindheimeri (whirling butterflies), Goniolimon
species (statices), Limonium species (statices), Linum perenne (blue
flax), Mirabilis multiflora (hardy four o¹clock), Oenothera species
(evening primroses), Penstemon species (most penstemons), Perovskia
atriplicifolia (Russian sage), Ratibida columnifera (prairie
coneflower), Tanacetum densum var. amani (partridge feather),
Zauschneria garrettii (California fuchsia), Zinnia grandiflora (golden
paper flower), hardy cactus species

XX-rated: Achillea species (yarrows), Agastache species (hyssops),
Alcea species (hollyhocks), Alyssum montanum (mountain gold), Anchusa
species (buglosses), Anthemis tinctoria (chamomile), Arabis caucasica
(rock cress), Arenaria species (sandworts), Armeria maritima (sea pink),
Artemisia species (white sages), Aster species (asters), Aurinia
saxatilis (basket of gold), Baptisia australis (blue false indigo),
Belamcanda chinensis (blackberry lily), Boltonia asteroides
(starflower), Brunnera macrophylla (Siberian forget-me-not), Centaurea
montana (perennial cornflower), Ceratostigma plumbaginoides (leadwort),
Delosperma species (ice plants), Dendranthema € grandiflorum (garden
mum), Dianthus species (pinks), Diascia integerrima ŒCoral Canyon¹
(twinspur), Erigeron species (fleabanes), Gazania species (gazanias),
Geum species (geums), Gypsophila species (baby¹s breaths), Helianthemum
nummularium (sun rose), Heliopsis helianthoides (false sunflower),
Hemerocallis species (daylilies), Iris germanica (bearded iris), Knautia
macedonia (red pincushion), Kniphotia uvaria (red hot poker), Lavandula
angustifolia (English lavender), Lavatera thuringiaca (tree mallow),
Lychnis coronaria (rose campion), Malva alcea (rose mallow), Nepeta x
faassenii (catmint), Origanum species (oreganos and marjorams),
Osteospermum barberiae var. compactum (sun daisy), Paeonia lactifloa
(peony), Papaver species (poppies), Phlomis cashmeriana (Jerusalem
sage), Phlox subulata (moss phlox), Platycodon grandiflorus (balloon
flower), Polemonium caeruleum (Jacob¹s ladder), Polygonum affine
(Himalayan border jewel), Potentilla species (cinquefoils), Pulsatilla
vulgaris (Pasque flower), Rudbeckia species (black-eyed Susans), Salvia
argentea (silver sage), Salvia species (salvias), Santolina species
(lavender cottons), Scabiosa species (pincushions), Sedum species
(stonecrops), Sempervivum species (hens-and-chicks), Solidago species
(goldenrods), Stachys plumbaginoides (lamb¹s ears), Tanacetum niveum
(snow daisy), Thymus species (creeping thyme), Veronica species
(speedwells)
X-rated: Ajuga reptans (bugleweed), Alchemilla mollis (lady¹s mantle),
Amsonia hubrichtii (blue star), Anemone species (windflowers), Aquilegia
species (columbines), Bergenia cordifolia (pigsqueak), Campanula species
(bellflowers), Coreopsis species (tickseeds), Delphinium species
(delphiniums), Digitalis species (foxgloves), Echinacea purpurea (purple
coneflower), Epilobium species (fireweeds), Euonymus fortunei
ŒColoratus¹ (purple-leaved wintercreeper), Galium odoratum (sweet
woodruff), Geranium species (geraniums), Hedera helix (English ivy),
Helenium autumnale (sneezeweed), Helleborus species (Lenten roses),
Heuchera species (coral bells), Hosta species (plaintain lilies),
Hypericum calycinum (St. John¹s wort), Iberis sempervirens (candytuft),
Lamium galeobdolon (yellow archangel), Lamium maculatum (dead nettle),
Leontopodium alpinum (edelweiss), Leucanthemum x superbum (Shasta
daisy), Liatris species (gayfeathers), Lychnis chalcedonica (Maltese
cross), Prunella laciniata (self heal), Pulmonaria species (lungworts),
Saponaria species (soapworts), Tanacetum coccineum (painted daisy),
Tradescantia species (spiderworts), Verbena canadensis (rose vervain),
Vinca species (myrtles and periwinkles), Viola corsica (Corsican
violet), Waldsteinia ternata (barren strawberry)
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Reprinted with permission from the March 2003 _HortIdeas_. Copyright
2003 by Greg and Pat Williams. HORTIDEAS (ISSN 0742-8219) is published
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--
Bob Batson


"Eagles may soar, but weasels don't get sucked into jet engines"