Tuesday, June 13, 2006

Extreme Hostas




Photo: Hosta 'Tea and Crumpets' www.songsparrow.com

First published in The Landscape Contractor magazine

“Little and Large: Extreme Hostas,”

By Becke Davis

For years, hostas have been one of the top selling perennials in the United States, competing with daylilies for easy care and familiarity. If you drive around suburban neighborhoods, though, you would mainly see fairly ordinary looking, green and cream variegated, wavy leaved hostas. Even though hostas perform best in shade, you don’t have to look far to see hostas surrounding rural mailboxes, dried out and burned brown.

Planting hostas in the right place is easy enough – most prefer shade, although deep shade is not the best option. Some studies show that more important even than shade is soil that is consistently moist. Hostas in moist soil are better able to withstand the hot sun. Gold hostas are supposed to be more tolerant of sun than blue or green hostas, but no hostas should be the first choice for a site that gets hot afternoon sun and tends to dry out. Filtered shade and rich, moist soil will bring out the best in most hostas. For hostas that are dark green, almost black, nearly full shade is needed to preserve the dark coloration.

Because hostas are common – it would be hard to find a yard without at least one hosta in it – some people equate common with boring. If you have never really looked at hostas, you may be surprised to find hostas that are six feet across, as well as others that, full grown, would fit in the palm of your hand. These extreme hostas – the largest and the smallest of the genus – are not for every landscape, but they can be wonderful, easy care specimens where the site and design allows for their special features.

The chartreuse ‘Sum and Substance’ (60” diameter x 30” high) has drawn media attention for years as one of the best of the big hostas. It has remained near the top of the American Hosta Society’s popularity poll for years, and in 2004 it was selected as the American Hosta Growers Association’s Plant of the Year. Now the focus has shifted to ‘Titanic’ (PP#12,402), a sport of ‘Sum and Substance’ featuring ribbed, variegated foliage with a gold edge and dark green center. The ultimate size of ‘Titanic’ is about four feet high by five feet wide, although some experts believe the size at maturity may reach 80 inches in diameter. Another hosta similar to ‘Sum and Substance’ is the variegated ‘Sum of All’, reaching 60” in diameter and 36” in height. ‘Solar Flare’ is a large hosta with yellow-gold leaves but it doesn’t quite reach the size of ‘Sum and Substance’, reaching only 52 inches wide and 28 inches high.

Some of the better known giant-sized “blue” hostas include ‘Am I Blue’ (45” x 30”), ‘Bigfoot’ (70” x 30”), ‘Blue Angel’ (up to 70” in diameter and 48” high), ‘Blue Mammoth’ (70” x 45”), ‘Blue Umbrellas’ (48” x 36”), H. sieboldiana ‘Gray Cole’ (some experts believe the ultimate width on this cultivar will reach over 84” with a height of 36”), ‘H. D. Thoreau’ (84” x 38”), ‘Krossa Regal’ (72” x 36”), ‘Mr. Big’ (80” x 40”), ‘Sea Blue Leather’ (52” x 36”), and H. sieboldiana ‘Elegans’ (up to about 40” x 30”).
Giant “green” hostas include ‘Abiqua Blue Shield’ (50” x 22”), ‘Behemoth’ (48” x 36”), ‘Bethel Big Leaf’ (56” x 36”), ‘Big Boy’ (48” x 36”), ‘Big Sam’ (48” x 36”), ‘Birchwood Elegance’ (48” x 36”), ‘Colossal’ (48” x 28”), ‘Corduroy’ (60” x 36”), ‘Green Acres’ (52” x 42”), ‘Jolly Green Giant’ (44” x 32”), ‘Placemat’ (60” x 30”), ‘Regal Rhubarb’ (56” x 32”) and H. nigrescens ‘Elatior’ (up to 40” x 30”). ‘Mountain Snow’, a green and white variegated hosta, reaches up to 60 inches across and 28 inches high. The variegated ‘Frosted Jade’ reaches up to 60” wide and 28” in height. ‘Sagae’ is a variegated blue hosta growing up to 70” in width and 30” in height, while ‘Yellow River’ may reach as much as 80” wide and 36” tall.

Among the smallest hostas are the fragrant cultivars ‘Asuka’, ‘Kunpu’ and Otome No Ka’. ‘Fragrant Tot’ has yellow leaves streaked with green and reaches only 6 inches in diameter and 4 inches in height. ‘Geisha’ (6” x 4”) has chartreuse leaves with a green margin. ‘Goody Goody’ has white leaves with a green margin and reaches 8 inches in diameter by only 2 inches high. ‘Bobbin’, a dwarf form of ‘Silver Kabitan’, is the smallest hosta in the “erect” group, with a diameter of about 4 inches and a height of only 2 inches. The “Tiny Group” of hostas includes ‘Abiqua Miniature’ (7” diameter x 3” high), ‘Blue Ice’(8” x 4”), ‘Gosan Gold Midget’ (5” x 3”)’, ‘Ivory Pixie’ (8” x 6”), ‘Shining Tot’ (6” x 2”), ‘Thumb Nail’ (4” x 2”), ‘Tiny Tears’ (4” x 2”) and ‘Tot Tot’ (8” x 4”).

‘Gold Colleen’ is a yellow-leaved form with striped purple flowers that only reaches 6 “ in diameter and 8” in height. ‘Golden Spades’ has a similar size and description. The Korean species Hosta venusta forms a dense, spreading mound reaching about 10 inches wide and but less than 3 inches high. ‘Blue Ice’ has the rippled blue leaves often found on giant hostas, but this time in a compact form only 10 inches wide by 6 inches high. Hosta ‘Little Bo Peep’ is a variegated, mounding hosta reaching just over 8 inches in width and 3 inches in height. ‘Cat’s Eyes’ has dark green margins and yellow centers that turn to ivory-white, growing to 6” wide and 2” tall.

Exceptionally large or small hostas can always be used as specimen plants, but they don’t have to be singled out. Tiny hostas can be used as rock garden plants, as edgers, or even in containers or trough gardens. Very large hostas can be used in perennial beds and borders, in large containers, or in some cases even as ground covers. The striking cultivar ‘Pineapple UpsideDown Cake’, for example, would make an ideal ground cover for semi-shade because it grows up to 50 inches in diameter but only reaches about 18 inches in height. The ripply cream-colored leaves have a very fine dark green variegation on the margins. Hosta ‘Rippling Waves’ is another good ground cover, with a mounding habit reaching 74 inches wide and 22 inches high. ‘Pewter Frost’ is a blue form suitable for ground cover, growing over 40 inches wide and 14” high. Hosta ‘American Halo’ features leaves variegated with dark blue green centers and yellow to cream margins, growing in a dense mound to about 72” wide and 22” high.

WHAT THE EXPERTS SAY

Both extremely large and extremely small hostas can make fascinating container specimens. Hosta grower Sandie Markland discussed planting hostas in containers in The Hosta Journal, a publication of the American Hosta Society (www.hosta.org):

“As many of us have learned the hard way, not all hostas are created equally. A hosta which performs beautifully in the Upper Midwest may prove a dismal failure in warmer climates. The same holds true when considering plants for container culture. With the notable exception of plants with Hosta sieboldiana and H. ‘Tokudama’ heritage, most hostas will do well in pots of appropriate size. H. sieboldiana, H. ‘Tokudama’ and many of their offspring may fare well in the short term, but my experience has shown a marked and sometimes rapid decline when kept in pots for more than a season or two.

“The container chosen for any given plant should be appropriate to the actual size of the plant, not its ultimate size. There should be no more than two to three inches of space between the outside wall of the pot and outermost roots of the plant. With more rapidly growing varieties, you may need to pot up each year, but it is well worth the effort in order to grow a strong and healthy specimen. Never plant a young, tiny plant in a large container. Chances are, it will languish and die."

Markland recommends retail potting mixes such as the brand names Jungle Growth, Lowe’s Professional Potting Mix and Sam’s Magic Earth (available at Wal*Mart), noting: “While slightly different in composition, all three have certain elements in common. they are low in both peat and perlite content, contain pine bark fines and other finely ground organic materials, are light to medium weight with good drainage and excellent moisture retention, and are inexpensive.

“Potting mixes heavy in peat should be avoided. Once the peat dries out, it is next to impossible to re-wet and, if you do manage to re-wet the mix, it remains soggy for quite some time. This is a real problem in winter. While perlite is useful in preventing compaction, it adds nothing else to the mix. It is far better to use something such as pine bark fines. They maintain space and, as they decompose, feed earthworms and beneficial microbes in the mix, which, in turn, feed your plant.”

In normal weather, Markland waters her potted hostas deeply once a week, twice if the weather is very hot and dry. “During my weekly watering, I fill each pot at least three times and let the water drain through the pot and out the bottom (always leave at least an inch or two of space between the soil line and the rim of the pot for this purpose). Watering in this manner serves two purposes. First, it ensures a thorough watering of the root zone and, second, it prevents the build-up of harmful salts in the soil.” 1

Carol Szalacha, a perennial specialist at Gethsemane Garden Center in Chicago, likes ‘Sum and Substance’ the best of the large hostas. “The foliage is a light apple green color, and it can get as high as four feet – it makes a good background plant. The leaves alone are the size of a small bar tray!

“Hosta sieboldiana ‘Elegans’ is another of my favorites – it makes a beautiful large clump, has white flowers and heavily corrugated blue leaves. Hostas with those heavily corrugated leaves are much more slug resistant thant others. In my own yard, one mature ‘Elegans’ hosta hides a tree stump, while others form a backdrop to a pond. Hostas are very drought –tolerant when established but they like water. Likewise, they will grow in almost any soil but they will thrive in composted soil or soil that is rich in organic material.

“Of the small hostas, ‘Pandora’s Box’ stands out. Its almost-round leaves are green with white trim. It grows to 6 inches tall and is a nice spreader – the plants in my yard almost doubled in size in one year. I think it spreads better than H. venusta.
‘Twist of Lime’ is another nice small one in two shades of green – a pretty light green and chartreuse. It has a traditional hosta leaf shape and grows to 8 – 10 inches high, filling in rapidly.

"‘Little Mouse Ears’ is a new one we just got in – I haven’t tried it yet in my own garden. It is sometimes hard for us to get the new or specialty hostas even though we do carry some expensive hostas. In a few years when the price goes down we should be able to get them.”

END


SOURCES:

THE COLOR ENCYCLOPEDIA OF HOSTAS by Diana Grenfell and Michael Shadrack, 2004, Timber Press, Portland, OR

THE GENUS HOSTA by W. Georg Schmid, 1991, Timber Press, Portland, OR

American Hosta Society website: www.hosta.org

American Hosta Growers Association website: www.hostagrowers.org

“The Genus Hosta, Chicago Style,” compiled by Rommy Lopat, The Weedpatch Gazette, Volume IV, No. 6, Summer 1996

Assorted retail mail order catalogues featuring new hosta cultivars

1“Shattering Some Myths About Hostas in Containers,” by Sandie Markland, The Hosta Journal, Volume 31, Number 1, Spring 2000

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