The one glaring exception is that hostas are deer favorites. If you live in deer country you know that plantings featuring tulips, hosta and daylilies are the equivalent of “all you can eat” buffets for Bambi.
It's a little unfair to start with the only major weakness of hosta, so let's move on and embrace the immense contribution that hostas contribute to any shady garden. Hostas are natives of the Far East, with their central distribution being Japan. They prefer part-shade (defined as between 4-6 hours of sun in mid-summer) to shade (if they receive no sunlight they might survive, but won't thrive). Hostas will tolerate more sun if they are grown in rich, well drained soil with a minimum of one inch of water per week during the growing season. If the edges of hostas turn brown they're either in too much sun or not receiving enough water. Hostas with yellow or chartreuse leaves require at least 3-4 hours of sun to exhibit their brightest colors. Additionally, hostas grown for their attractive, fragrant blossoms will produce more flower scapes in sunnier locations. Many of the larger hostas are quite tolerant of clay, but they'll thrive and establish more readily if you take the time to incorporate compost when planting. Slugs are the only other pest to trouble hostas. There are organic and chemical controls available for slugs. My preferred method is to step on them. It's effective and non-poisonous, but not fun for the squeamish.
Hostas are grown primarily for their foliage--paddle shaped leaves ranging in size from tiny spatulas to large platters. The American Hosta Society classifies hosta by leaf size (ranging from giant to dwarf) and shape (oval, round, elliptical and lance-shaped). Additional characteristics in classifying hosta are available on the American Hosta Society's website.
While it's fairly easy to satisfy the cultural requirements for growing hosta, the really tough decision is where to start when choosing from the thousands of cultivated varieties available at garden centers or via mail-order from hosta specialists. I am not a collector of hostas, but in my typical suburban garden I grow over a dozen different hosta cultivars. In a shady area, where floral display can be limited, the bright white or lively gold of hostas create an impact like no other plant. The foliage color spans the entire growing season and the chunky texture of hostas contrasts beautifully with finer textured plants such as ferns.
Many gardeners become collectors of hosta. If you must create a "hosta garden" underplant your collection with a well behaved groundcover such as sweet woodruff (Galium odoratum), rather than a sea of bark mulch. In my garden I prefer to create vignettes with hosta, pairing them with perennials or annuals that complement their color or size.
My current favorite is Hosta 'Sagae', a large, dramatic plant with blue-green leaves edged in bright yellow-to-cream. I have it growing in front of goat's beard (Aruncus dioicus), a tall plant with fern-like foliage and cream colored plumes in early summer and, at its base, a planting of Serbian bellfower (Campanula poscharskyana) whose blue flowers enhance the yellow edges of 'Sagae'.
A time-tested medium size hosta is 'Halcyon', whose glaucous blue foliage is maintained over the entire growing season. Hostas with blue foliage are more resistant to slug damage than those with green or yellow leaves. 'Halcyon' has lived happily in my garden for almost 20 years. It pairs well with Japanese painted fern (Athyrium niponicum 'Pictum') and bronze beauty carpet bugle (Ajuga reptans 'Bronze Beauty').
One of the cutest hostas available is the miniature 'Blue Mouse Ears'. A perfect bun shaped cluster of tiny (3"x2") rounded blue leaves form a clump about 12 inches wide and 7 inches tall, making it perfect for the edge of a shady border. Miniature lavender flowers appear in late summer.
Another dwarf hosta, with chartreuse leaves, is Hosta 'Lemon Lime'. The leaves of 'Lemon Lime' are lance-shaped and slightly rippled, 3 ½ inches long and half as wide. In my garden its golden leaves are paired with Campanula 'Kent Belle' and Japanese forest grass (Hakonechloa macra aureola). The campanula's cobalt flowers complement the lime foliage beautifully and the grass adds a nice textural contrast.
If you're tackling a shady spot in your garden, be sure to check out the myriad of choices offered by the genus Hosta. Once you start adding hostas to your garden, you'll find they're like potato chips. You'll definitely want more than one!
Carol Papas, Penn State Extension Master Gardener, Allegheny County