Pink, heavily veined flowers are the attraction of Geranium asphodeloides.  Growing to only about 12 inches in full sun/part shade and well-drained soil, the border is the perfect spot for this perennial hardy Geranium.  If the plant begins to look untidy during the summer, give it a quick pruning, and it's good to go.  It's also a good idea to cut this true Geranium back to the ground in the fall and add a little mulch for extra protection.  Zones 6-9.  Quarts.

Geranium "Brookside" is another true Geranium that I really like because of the cooling effect of the blue-violet blooms.  It is one of the prettiest colors I know of in the plant kingdom.  This hardy Geranium grows to about two feet in full sun/partial shade.  The word
on the street is that Geranium "Brookside" can sometimes become leggy, but that's easy enough to take care of with some pruning shears and two seconds of your time.  If you ask me, it's  much-ado about nothing, and I haven't let that dissuade me from planting this beauty in my garden.     Zones 5-8.  Quarts.

This hardy Geranium is so similar to "Karmina" that they could almost be twins - fraternal twins anyway.  While "Karmina" is a deep, no doubt about it pink,
"Biokovo" is, well, different.  You can't call it exactly white, and you can't call it pink either.  It's somewhere in between, and that's what I like about it.  In a way, I think the color is more refreshing than "Karmina," but I like them both.  "Biokovo" grows to about eight
inches and, like "Karmina," has scented leaves that turn brilliant red in
fall.  That's the best part about it if you ask me.  Sun in Zones 5-9.  Quarts.

Geranium macrorrhizum "Bevan's Variety," or Big Root Geranium, is a hardy Geranium that looks especially charming where it has a wall to spill over or stones to crawl between.  The magenta blooms of "Bevan's Variety" keep coming and coming as long as you deadhead; it also spreads nicely,  making a most attractive ground cover.  Oh, and one more thing:  it has a very definite, unmistakable scent.  You either love it or you hate it.  Sun or shade.  Zones 4-9. Quarts.

Geranium macrorrhizum "Bevan's Variety," or Big Root Geranium, is a hardy Geranium that looks especially charming where it has a wall to spill over or stones to crawl between.  The smaller, darker blooms of "Karmina"  keep coming and coming as long as you deadhead; it also spreads nicely, making a most attractive ground cover.  Sun or shade.  Zones 4-9. Quarts. (Photo by Kenpei, from Wiki Commons.)

This hardy native Geranium is just as
becoming in its woodland habitat as it is in the garden border.  Growing to  nearly 12 inches in height,  its bright pink/lavender blooms stand high above its lush foliage.  Geranium maculatum   brightens any spot,  whether that spot
happens to be in sun or shade.  If you
have a hillside to spare, they are particularly effective planted  in large
drifts.  Geranium maculatum is just another example of the unsurpassed  beauty of native wildflowers.   Zones 4-8.  Quarts.

Geranium maculatum alba is the white flowering
form of the native wildflower, Geranium maculatum.  "Alba" grows to about 12 inches in sun/part
shade and will brighten any spot.  I have grown "named" varieties of this native white Geranium maculatum that are touted as being superior to the species, but so far I have been disappointed.  I think this one proves them all wrong.   Zones 4-8.  Quarts.

Geranium nepalense v. thunbergii is new to my garden. This hardy Geranium has the typical Geranium foliage and growing
habit and is covered in small, bright carmine pink flowers all summer long.  Occasionally, a white-blooming one will  come along (see photo below), and that's even better, if you ask me.  It has a sprawling habit, so it needs to be cut back occasionally to keep it in check, but other than that, you have a splash of color from this plant all summer long.
Sun/partial shade, and a little pruning from time to time.    Zones 4-9.  Quarts.

No photo yet, but you can see this profuse violet bloomer here. This Geranium is new to me, and I have not grown it myself, so I am relying on the rave reviews of others and its popularity instead.  This hardy, easy to grow Geranium grows to about 15 inches high by 20 inches wide (at maturity) and is literally covered in small, violet blue, blooms for months on end.  Given a good shearing after blooming, it is said to spring right back for another show.  This clump-forming perennial is slug, deer, and rabbit resistant; bees love it; and it is evergreen and drought resistant.  Whew, that's a lot!  It also self-sows and for some folks, that may present a problem, but not for me.  Zones 5-9, Sun/part shade.

"Philippe Vapelle" grows from 10 to 12 inches high in full sun/partial shade and boasts large purple/blue flowers and heavily patterned grey/green foliage that is almost as alluring as the blooms.   Zones 5-8.  Quarts

Geranium pratense is a hardy geranium that  stands 12
inches tall and has an endearing loose, airy habit.  The lavender/blue saucer-shaped blooms have the color that has the uncanny ability to  cool you off on a hot day just by being in its vicinity.  Geranium pratense is striking in the garden border and is a long
bloomer, too, if  deadheaded before seeds set.   Sun/partial shade, moist soil.  Zones 4-9.  Quarts.

Highly popular in the England, Geranium pratense "Mrs. Kendall Clarke" is a soft
violet blue, heavily veined in white, hardy Geranium. Growing from two to three feet, it may need staking, but I always let mine ramble where it likes because I like its beautiful blooms peeking at me through other flowers.  Be sure to cut back "Mrs. Kendall Clarke" heavily after its first bloom for a second flush of color.  This hardy Geranium tolerates drought and overly damp soils after becoming established, and after it does, Geranium pratense "Mrs. Kendall Clarke"  thrives for a long time
in full sun/part shade in Zones 4-9.  Quarts.

Geranium robertianum (Herb Robert), is a little different from the other hardy Geranium varieties listed here in that the deep green, transitioning to deep reddish purple,
foliage is fern-like.  It is also considered an annual or biennial, but not to worry:  Geranium robertianum is a vigorous self-seeder, and it will make an appearance (maybe too many) every year anyway.  Growing to about 10 inches with tiny, bright purplish rose flowers, Herb Robert is in bloom almost constantly from spring through fall, and in winter, the garnet-hued foliage adds interest in abundance to the landscape.  Sun/part shade in Zones 5-9.  Good to know:  Herb Robert was once used as a remedy for toothaches and nosebleeds, and it is said that if the leaves are rubbed on the body, their odor repels mosquitoes.  And, not only that, but the resinous secretion from the leaves was once used to cure the plague.  And who was this Robert that this plant was named for?  Some believe it was Saint Robert, a Benedictine monk to whom April 29 is dedicated, which is the day the plant is said to come into flower in Europe (more or less), and Robert, Duke of Normandy, for whom the "Ortus Sanitatis," a standard medical  guide was written and used for a century.

"Celtic White" is the white flowering version of  Geranium robertianum with pristine white, five-petalled flowers instead of pink.  I don't think the foliage will have the same red hue, but the flowers will be just as charming.  Sun, part shade in Zones 5- 9. (No photo yet; beautiful rendering of Geranium robertianum by Jacob Sturm, 1796, from Wiki Commons)

This low growing, slowly spreading hardy Geranium is perfect for edging or growing among rocks.  Its vivid, rosy-purple
blooms will be around for a long time, and the red-tinted
foliage in fall is a plus.  Sun/part shade, well-drained soil.  Zones
4-7.  Quarts

This hardy Geranium grows from 14 to 16 inches high and isn't a bit stingy with its blooms.  It is covered with bright lavender/pink, darkly veined flowers beginning in spring and reappearing off and on throughout the summer.  If you give it a good pruning, it will rebloom in late summer, too. The deeply cut
foliage is abundant and attractive in its own right, so with or without flowers, this geranium is an asset to the perennial border.  Sun/partial shade.  Zones 4-8.  Quarts.