Calamintha

grandiflora Calamint
‘Elfin purple’   Charming bright rose flowers open like miniature Penstemons on a compact, lush plant. Great for borders or rock gardens. To 16” tall and wide.  Full sun, light shade in hotter areas, moderate water. Zones 6-9

Calandrinia

umbellate: Closely related to portulaca, an annual with narrow fleshy leaves, flowers are showy with broadly overlapping petals in pinks and purples.

Calendula 

English Marigold
‘Bon-Bon’ Series Dwarf, compact w/ 3” flower heads, to 12” tall

Calibrachoa

Tender perennial.  These beautiful plants are another must have in your container program.  They are like miniature trailing "petunias".  Provide good drainage, full sun to light shade.  Height to 6" Zones 8-10
‘Brilliant Cherry’ cherry flowers
'Celebration' Series smaller, more floriferous, with a yellow eye. Blue, Red, Sun (Yellow), & Apricot (like Terra Cotta)
'Liricashowers' Series, smaller flowers with yellow throats
‘Minifamous Series', strong colors with yellow throats
'Million Bells' Series' Medium to large blooms
‘Purple Red’ purple – red flowers
‘Starlette’ Series self-cleaning, high impact colors, mounded-trailing habit
‘Violet Blue’ violet-blue flowers

Callirhoe

involucrate: Prostrate growing groundcover with geranium like leaves and poppy shaped flowers, magenta with yellow to white centers. Zones 3-8

California Poppy  see Poppy

Calocephallus brownii

Calyophus

drummondiamus: Bright clear yellow flowers, needs well drained soil

Campanula                                

Bellflower: Perennial.  This is a diverse genus with plants for the entire garden.  All of these plants will be covered with bell-shaped flowers in early summer.  It is an excellent choice for rock gardens and the perennial border.  Part sun to part shade. 
'collina'   Basal rosette of foliage topped with 12" spikes of purple blooms. Height 4-12",
'garganica' Adriatic Bellflower: A dwarf trailer with dark green foliage. Covered with blue star shaped blooms.  Height 2-6", 12” or more width
'glomerata' Clustered Bellflower: Vigorous plant with round clusters of purple-blue flowers in early summer, alba is a white flowered selection  4-18" tall.
'lactiflora' Milky Bellflower: A mix of white, lilac and pale blue flowers towering over basal, oblong leaves. Great cut flower. Height 3’ to 5’, 2’ wide, may need staking
'latifolia' Blue Long spikes with tubular, upright, bell-shaped flowers. Leaves have a rough texture, vigorous, pale to deep violet  Height 30-40"
'medium' Canterbury Bells: Biennial.  Bell-shaped single or semi double flowers on sturdy upright plants.  Often flowers in the first year here in CA.  Available in Blue, Lilac, or Rose.  Height 30-40"
'Bells of Holland' a dwarf form of C. medium, this dome shaped plant is covered with large bells in blue, mauve, rose and white.
'Chelsea' series Annual.  This cultivar is great for cut flowers.  Bell shaped flowers in pink or blue are borne on sturdy stems.Height 12-15"
‘Cup and Saucers mix’ A unique flower type that differs from the species in that the flowers have an additional calyx at the base giving it the appearance of a cup sitting on a saucer.  Available in a Mix of pink, blue, white, and lilac. Height 24-30"
'ochroleuca' Creamy-white bells, 24” high, Zones 6-8
'persicifolia' Peachleaf Bellflower: Basal leaf cluster topped with upturned, cup shaped violet/blue flowers.  Height 48-60"
'poscharskyana' Serbian Bellflower: Lilac blue flowers on trailing heart shaped foliage. Height 8-12"
'primuaelifolia' Blue Oasis: compact plant which in bloom is covered with azure blue flowers
pyramidalis Chimney Bellflower: A prolific bloomer with bell-shaped, light blue to white flowers.  Very fragrant.  Height 40-50"
rapunculoides  Tall spikes with nodding blue, star-shaped flowers.  Height 30"
rotundifolia  ‘Olympia’ Violet blue bell shaped flowers over a round basal leaf cluster.  Height 6-12"
‘Samantha’ A slow spreader that forms a mat with 1” soft blue-violet flowers, re-blooms sporadically with deadheading, Zones 5-8

Carnation also see Dianthus

‘Cinnamon Red Hots’: deep red flowers over green foliage, re-blooms frequently, simply one of the best.
‘Da Vinci’ pink, fully double flowers with compact growth habit and gray foliage
‘Dimple’ rose, fully double flowers with compact growth habit and gray foliage
‘Dinah’ white, fully double flowers with compact growth habit and gray foliage
‘Diogenes’ deep pink, fully double flowers with compact growth habit and gray foliage
‘Discovery’ scarlet, fully double flowers with compact growth habit and gray foliage
‘Grenadin’ Series mostly double, fringed, clove-scented flowers, 2” across, in red, yellow, white, & bicolor
‘Julia’ pink
‘Michelangelo’ rose
‘Romeo’ red
‘Smarty Series’ available in lavender-rose, Bordeaux (red), light red, and salmon pink

Catanache

caerulea Cupid’s Dart:
‘Amor Series’ an elegant plant with fine flowers on long slender stems and grayish foliage. Can be used as fresh or dried cut flower. 21”. Zones 4-7
‘Amor Blue’ purplish blue w/ dark blue center
‘Amor White’ suffused white with purple center.

Celosia

Annual
‘Century Mix’ plumosa type, vivid red, rose-pink, or yellow, to 18”
‘Flamingo Feather’ good for cutting or drying, pink toward the tips, silvery white at the base, to 7”
‘Kimono Series’ very uniform, dwarf, feather/plumosa-type Celosia, 6” to 8” tall
‘New Look’ plumose-type, dark purple-green foliage, deep red flowers, to 18”

Centaurea

cyanus: Annual with intense, deep blue 2 1/2” powder-puff flowers on 30” high stems, full sun, low water requirements.
'Florence' Series Bachelor’s buttons, Annual.  This vigorous plant has gray-green leaves and a mounding habit. Available in blue, pink, red, or lavender.  Full sun to light shade, good drainage, Height 8-10".  

Centranthus

ruber Jupiter's Beard: Perennial.  This plant is very generous with its seeds!  Its blue-green foliage is covered with funnel shaped flowers for most of the season.  It will age into a small shrub.  A very drought tolerant selection. Full sun to partial shade.  Height to 36”.  Zones 6-10
'Pretty Betsy' Dark pink blooms.
‘Snowcloud’ White blooms

Cerastium

Perennial.  This is a vigorous, low growing genus known for its shimmering silvery foliage. It is very drought tolerant.  Filtered sun.  Height 10-12".   Zones 4-9 
'biebersteinii' White flowers. More vigorous than tomentosum, a little taller as well, really a nice species.
tomentosum:
'Snow in Summer’ fast growing ground cover, white flowers, silver-gray foliage
‘Silver Carpet’ extra dwarf, silver foliage and white flowers

Ceratostigma

plumbaginoides excellent hardy ground cover, azure blue flowers in late summer, striking red foliage in fall.

Chaenorrhinium

‘Blue Eyes’ small fragrant leaves, good for rock gardens, small fluted blue flowers

Cheiranthus

cheiri  (Erysimum)Wallflower
Perennial.  This plant is an excellent choice for containers.  The glossy, dark foliage is an excellent foil for the bright star-shaped flowers. You will be rewarded with a multi-season display of color.  Full sun to partial shade.  Height 14-16".  Zones 7-9
‘Charity Series’ early to flower, extra dwarf, good for containers, a mix of cream yellow, rose red, scarlet and yellow
'Gold Shot' Golden-yellow flowers.
'Little Kiss' basal-branched biennial plant can be grown as an annual. Lilac-mauve flowers. 12”.

Chrysanthemum see also Leucanthemum

hosmariensis: Perennial.  (Renamed Pyrethropsis gayana) This shrubby perennial has lacy gray foliage, like a Dusty Miller, but has the flower of a Shasta Daisy.  It needs little care or water; making it a great choice for naturalized areas.  Continual bloom, heaviest in late winter early spring.  Full sun to part sun.  Height 18", 4' spread. 

Cineraria

‘Jester Mix’ Compact and rounded habit with long lasting brightly colored daisy-like flowers in blue, carmine, crimson, pink, and scarlet

Clematis

tangutica 'Radar Love': Perennial.  This climbing vine is excellent for trellis and fence applications.  It will do best in full sun, but the roots must be shaded.  The golden star shaped flowers mature into unique, decorative, feathery seedpods. Blooms first year, prune after bloom.   Zones 4-8

Cleome

hasslerana 'Queen Mix' Annual.  This is an old-fashioned border plant with interesting spider-like blooms.  Your grandmother probably had a few in her garden! Available as a mix of cherry, rose, violet and white.  Keep on the dry side.  Full sun.  Height 36-48". 
‘Linde Armstrong’compact & thorn less, lavender-pink flowers, 10-16” tall

Cobbity Daisy see Argyranthemum

Coleus                        

solenostemon: A tender perennial that does best with temperatures of 45 degrees and above, large range of leaf shapes, sizes, and colors.  Need protection from cold and hot sun.  Varieties with more red to leaves “tend” to be more sun tolerant
‘Alabama’ Burgundy to red with lime green highlights, to 3’ tall
‘Amora’ butter colored leaves with green scalloped edges and red veins, very unusual
‘Black Dragon’ Large serrated leaves of an unusually deep color of red w/ purplish-black edge. To 12”.
‘Carefree Mix’ Plants are self-branching and remain compact throughout the growing season. Brightly colored leaves are small. 1 ½ “ long, and lobed like an oak  leaf.  8-12” tall, 10-12” wide
‘Combat’ 18”, crimson velvet veins and velvet leaves
‘Display’ red with chartreuse accents
‘Freckles’ Dark green highlighted with red, gold and deep burgundy, to 4 ft tall.
‘Giant Exhibition Mix’ This showy and colorful variety has extra large leaves. Especially selected for houseplant use, but is equally suitable for outdoors is shade during the summer. Beautiful, multicolored leaves.  18-24” tall & wide
‘Jade’ Deep Burgundy with a hint of green; yellow border; to 2’ tall
‘Kingwood Torch’ flaming magenta foliage overlaid with burgundy, vigorous grower'
‘Midnight’ deep purple with slender leaves
‘Mission Gem’ large leaf, pink striped purple with a fine yellow green marbled edge.
‘New Orleans Red’ dark red almost black with an iridescent bright cherry center
‘Pat Martin’ mostly red leaves with lime green tips, smoother margins
‘Peter’s Wonder’ deep violet, green and yellow, vigorous
‘Pineapple’ exotic foliage of maroon and lime green
‘Pineapplette’ yellow leaf, frilled edge, red speckles, vigorous but sturdy
‘Pineapplette Red’ deep red/maroon flowers
‘Red Duckfoot’ mostly dark red, unusual, smaller duckfoot-shaped leaves, to 18” tall, this variety is more sensitive to cold than most.
‘Red Ruffles’ Brilliant red/rose highlighted with a burgundy/black spot & lime green, to 18”
‘Rustic Orange’ -Dark salmon orange with yellow green margins 2 to 3 ft.
‘Red Velvet’ burgundy with red veining accents
‘Rose Blush’ large leaves, white dappled with green, crenulated edge, vigorous habit
‘Rustic Orange’ gold leaf with a wash of coral-red, less vigorous and great for containers
‘Saturn’ burgundy red foliage with chartreuse lime down the center and chartreuse scalloped edges.
‘Splash’ red with lime green margins
‘Sun Plum Parfait’ beautiful plum and pink foliage and very sun and heat tolerant. 14-18” tall
'Sunset' russet red
‘Volcano’ rounded leaves hot pink in the center then red, edges almost black
‘Walter Turner’ burgundy ruffled
‘Wild Lime’ Yellow center with ruffles, dark lime green, border type, to 20”  

Convolvulus             

Silverbush cneorum: Perennial.  This shrub has many soft hairs coating the leaves giving it a shimmery appearance. The stems arch upward from the base of the plant and end in silky pink flower buds.  The flowers open white, and the display will last all summer.  Full sun to part sun.  Height 24" Zone 8-10
'tricolor'  Annual.  These plants can adapt to many site conditions.  Large, multi-colored, Morning Glory flowers top these low growing plants.  They are perfect for bedding applications.  Plant in a sheltered area for best results.  Full sun, to 6” tall.  Zone 8-10.
'Choice Mix' Blue, pink, and white
'Royal Ensign' Deep blue w/gold center, freely branched, 2” flowers

Coreopsis

Perennial.  This genus of the daisy family is another North American native.  It blooms consistently through the summer.  The plants will become slightly woody as they age, and are very drought tolerant once established.  They will benefit from a yearly cutback.  Songbirds love the seeds!  Full sun.
'grandiflora':  This species has large, lance shaped leaves, and is covered with yellow daisy flowers in early summer.  This species reseeds readily.  Height 16-18". 
‘American Dream'  herbaceous perennial that can be grown as an annual, with cheerful flowers in shades of Rose-pink, spread 12”
'Early Sunrise' Double yellow flower
'Flying Saucers' Single yellow flower
'Sundancer' Double yellow flower
tinctoria ‘Dwarf Red’ bright mahogany red, single, 6” tall, 14” wide
verticillata   This species forms a neat mound of light, airy foliage covered with yellow daisy-like flowers.  Height 16-24”.  Zones 3-10.
'Moonbeam'  Lemon yellow flowers-
'Zagreb'  Bright yellow flowers

Cosmos

atrosanguineus 'Chocolate': Perennial.  Chocolate lovers beware. This plant really does smell like chocolate!  The medium green foliage is softly lobed and is topped with chocolate brown flowers. Full sun. Height 24". Zones 8-10
bipinnatus   Annual. These plants are a favorite in the cut-flower garden. They have beautiful feathery foliage, & are topped with large brightly colored, daisy-like flowers. Protect from frost. Full sun. 
‘Daydreams’  more numerous, smaller flowers, self-cleaning, semi-dwarf
'Pretty Picotee' White with red stripe and border.  Height 48"
'Seashells' Mix of red, pink and white. Height 30-40"
'Sensation' Mix of pinks and white. Height 36”
'Sonata' Series White or mix of white and pink shades. Flowers have a yellow eye, Height 20-24”
sulphureus 'Cosmic Yellow' & 'Cosmic Orange'
All American Winners, these stocky, free-flowering varieties have a well-branched habit. Height 12”, don’t over water!

Cuphea                      

Mexican False Heather: Perennial.  This genus puts on a terrific floral display.  However it will need some protection from severe cold.  Does well in hot climates. Full sun to part shade.
hyssopifolia This mini shrub has tiny-toothed leaves.  It produces thousands of tiny, tubular flowers through the summer and fall.  Height 16-18"
‘Firecracker’ trailing, great in baskets or containers, or as a groundcover, bright red flowers
‘Firefly’ magenta flowers that do not fade in high heat
‘Lavender Ice’
'Lavender Lace' purple/lavender flowers
‘Lilac’ lilac flowers
'Pink' pink flowers
‘Tundra’ small purple flowers and a very compact growth habit
'White' white flowers
llavea Batface Cuphea This plant has bushy, hairy foliage.  It received its common name because the flower resembles a bat.  Quite novel!  The flowers are a combination of red, orange and purple. Height 16-18"
‘Tiny Mice’ similar to Batface, red with purple accent, flower resembles a mouse with large ears, 6-8” tall

Cyclamen

persicum 'Sierra Series’: Perennial.  An old favorite for Christmas and Valentine's gifts, these showy plants actually perform remarkably well in the ground.  The marbled heart shaped foliage is topped by beautiful nodding flowers fall through spring.  Plant them in well-drained soil, and don't be worried if they go dormant in the hot summer months.  Shade to part sun. Height 6-8". 

Cymbalaria

muralis Kenilworth Ivy: Perennial.  A relative of the Linaria genus.  This trailing plant is covered with tiny lilac-rose flowers.  It is great for rock gardens, groundcover, or hanging baskets.  Full sun. Height to 4”. Zones 4-10.