The last time I wrote about this subject was in the Summer 2009 issue of The Hosta Journal (Vol. 40, No. 2, p. 67). The opening paragraph read:
 
                What’s both big and small, and getting a lot of attention? Miniature
                (mini) hostas. They’re big in popularity, and small in size, with new
                size criteria.

 
   Minis are still hot, perhaps even hotter now.
   This year The American Hosta Society initiated a new size definition for a mature mini or miniature hosta:


Leaf blade area no greater than about
6 square inches (39 square cm.)

   The previous (2009) definition was no greater than about 4 sq. in. (26 sq. cm.). Area is defined as leaf blade length multiplied by leaf blade width. Leaf length does not include length of petiole (leaf stem).  
   Mature is defined as at least five years of good growth from liner or plug size. Liners are the small plants wholesaled by tissue-culture propagation laboratories.
   Note there is no restriction on clump (mound) height and width. The 2009 mini size also did not have a limit on clump size.

Back Story

   In March 2010, an ad hoc committee was formed by the AHS president to clarify the size of mini hostas in the society. This was necessary to create uniformity in mini size specification for:

·         AHS Hosta Show classifications,

·         AHS Popularity Poll candidates,

·         Online Mini Forum (http://groups.yahoo.com/group/minihosta/) and

·         other activities.

Participants were:

·         Judy Burns, AHS Hosta Show Classification List Chair,

·         Robert “Bob” Olsen, The Hosta Journal Editor,

·         W. George Schmid, AHS Nomenclature Chair and

·         Robert “Bob” Solberg, American Hosta Growers Association Liaison.

   The size of a mini hosta within the AHS was standardized. Notably, it encompasses the size criterion used for AHS Hosta Show classifications. (I’ll discuss this in a few moments.)

   Prefixed to 6 sq. inches is "about". This gives needed “wiggle room” to leaf dimensions, especially leaf blade areas. Hostas are living growing things and highly precise measurements of leaf widths and lengths (and I’ll add clump dimensions too) are not practical. Important contributing factors are the age of the plant chosen for measurement along with cultural and environmental conditions. Not surprisingly, there often is bias – sometimes considerable – in which leaves are selected to describe a hosta’s size.

   At best, most leaf size measurements are +/- 1/16 inch, probably some only +/- 1/8 inch.  And let’s admit too, some dimensions in registrations, nursery catalogs and even esteemed reference texts are no more than guesstimates. They’re what someone thinks the dimensions might be at maturity. Many hostas are registered before they are mature. No doubt many sports are registered with their parents’ dimensions because the sports were but two or three years old at the time of registration.

   Differing from previous definitions of a mini hosta, the new AHS mini requirement includes an interesting new concept: H. ‘Blue Mouse Ears’ (E. & J. Deckert - 2000) is the “biological standard.” This hosta was selected because many AHS members, who have ‘Blue Mouse Ears’, know how big it usually gets and consider it a mini.

   Compared to the 2009 mini size, which is considerably smaller, the 2010 definition permits a larger selection of hostas to be classified as mini hostas for the AHS Miniature Popularity Poll. Starting with the 2010 poll, this is the new name of the AHS (Very) Small Popularity Poll, conducted by The Hosta Journal and printed in the summer issue for the last couple of years.    

BME is Garden Standard, not Biological Standard

   Including a standard reference hosta for AHS minis was Bob Solberg’s idea and has considerable merit. However, I would not have chosen the term “biological standard.” I think it is inappropriate and perhaps incorrect, implying something the standard is not. “Biological” is much too presumptuous, pedantic and academic sounding. At most, ‘Blue Mouse Ears’ (frequently called BME and pronounced bee-mee) is simply a “garden standard” – and that’s the terminology I’m using. The American Hosta Society is a gardening society, not a botanical organization.
   Nor would I have chosen BME. A prime reason is its customary, mature leaf size is at the very end of the limit of about 6 sq. in. In addition, more and more we’re seeing old clumps of BME with representative leaves markedly larger than this size. Often they are as large as 9 sq. in.; in other words, leaves are about 3 inches by 3 inches. Do you think a hosta with leaves 3 inches by 3 inches is a mini? I don’t! 
   A better choice, in my opinion, would have been ‘Pandora’s Box’ (H. Hansen - 1996), ranking Number 2 in the 2009 AHS (Very) Small Popularity Poll. It is a variegated-leaved sport of ‘Baby Bunting’ (R. Savory - 1992). There are several other variegated sports of ‘Baby Bunting’, but ‘Pandora’s Box’ is the better choice.
   I did a quickie survey involving two dozen keen hosta gardeners in summer 2010, mostly at the exciting FIRST LOOK 10 meeting in New Jersey in June, asking them: Which would be the better garden standard for a mini hosta, BME or ‘Pandora’s Box’? All grew both cultivars. Twenty said ‘Pandora’s Box’.
   But to give it its due, BME ranked Number 1 in the 2009 AHS (Very) Small Hosta Pop Poll, and it was the 2008 American Hosta Growers Association’s Hosta of the Year (HOTY), a noteworthy, flag-waving achievement. Most important too, BME is a good grower; it mounds up nicely and fairly quickly. In fact, it frequently outgrows the mini site originally allotted to it, especially in troughs and rock gardens. 
   Further, to be fair to BME, I need to mention that some gardeners report difficulty in growing ‘Pandora’s Box’. However, when ‘Pandora’s Box’ likes its site, it’s a showstopper.  
   Another BME advantage: a dozen or so sports have been found, some now heavily in the marketplace. Variegated-leaved BMEs are today’s sought-after mini hotties. I’m told sales interest in plain-leaved BME has markedly leveled off: If you’re a hosta fancier, BME is already in your garden. If it’s not, it isn’t because you don’t know about BME or can’t find a source. It’s simply because you don’t want to grow it (for whatever reason). 
'Blue Mouse Ears'
'Pandora's Box'
Comparison of the two
Is BME really a mini?
   Another paramount factor for selecting BME as the AHS mini’s garden standard, I suspect, is BME has a much larger leaf than ‘Pandora’s Box’: maybe twice the size. By having the mini garden standard at the very upper end of the AHS mini size limit, other hostas in this dimensional range will be recognized as being AHS minis. 
   Hosta leaves can have strap, lance, egg, heart (cordate) or round shapes. A mini size defined only by leaf blade area may be satisfactory for round and egg- and heart-shaped leaves, but not always O.K. for certain strap- and lance-shaped leaves. BME (and ‘Pandora’s Box’ too) have cordate or heart-shaped foliage. Might having the garden standard for a mini with this leaf shape imply that minis cannot be strap- or lance shaped too? Of course this is not intended.
   Here are a few outstanding minis not having BME’s leaf shape. H. ‘Lemon Lime’ (R. Savory - 1977), with registered leaf dimensions of 3 inches by 1 inch, is Number 8 in the 2009 AHS (Very) Small Hosta Popularity Poll. H. ‘Alakazaam’ (R. Livingston - 2008) has registered leaves 5 inches by 3/4 inch. Leaves of ‘Bitsy Gold’ (R. Savoy - 1985) also are 5 inches by 3/4 inches. H. ‘Curly Fries’ (R. Solberg - 2008) leaves are 5.5 inches by 3/4 inches and ‘Itsy Bitsy Spider’ (G. Johnson - 2004) leaves are 2.3 inches by 1/2 inch.

Leaf Blade Length: No Restriction

   You may have noted that the new mini size definition has no restriction on leaf blade length. The 2009 definition restricted leaf-blade length to no greater than 4.5 inches (11 centimeters).
   The problem is paramount for hostas with very long, very narrow leaves. Here’s a hypothetical example: Picture a hosta with leaves 11 1/2 inches long and 1/2 inch wide. The new size definition permits this hosta to be a mini because its leaf blade area is not greater than about 6 sq. inches. However, I seriously doubt any one would consider such extreme foliage to be a miniature hosta.
   The fix would have been to put a cap on leaf blade length. A leaf blade length of less than 6 inches would seem to be a good limit, though somewhat less or more might be O.K. too.
   Let me add that there would be a secondary benefit for a limit on leaf blade length. It also would limit clump (mound) height. There is this dichotomy: As long as leaf blade area is no greater than about 6 sq. in., technically the height of a mature, AHS mini clump can be any dimension.

Clump height?

     Clump size brings up a very “touchy” – and unresolved – subject. Mature mound height is used for defining hosta sizes. It is well recognized that from a practical gardening and landscape design perspective, this is a much better criterion for defining a hosta’s size than leaf blade area. That includes minis. Some hosta reference sources classify hostas by mound sizes, not leaf blade areas, as do many nurseries for descriptions in their catalogs and listings 
   Notable is Mark Zilis’ now classic The Hostapedia (Rochelle, Illinois: Q & Z Nursery. 2009). It defines a mini hosta as <8.0 inches mound height, citing H. venusta as archetypical. (Yes, this highly regarded hosta authority did not cite either ‘Blue Mouse Ears’ or ‘Pandora’s Box’.) Zilis defines a small hosta as having mound height of 8 to 12 inches.

'Frosted Mouse Ears'

 
   Unfortunately, in the nursery trade, there is no standard mini clump height. Naylor Creek Nursery in Washington State defines a mini hosta as having height of 3 to 4 inches. Marco Fransen’s Nursery in the Netherlands defines a mini hosta as having an average clump height of 4 to 8 inches. In addition Shady Oaks Nursery in Minnesota defines a mini hosta as having mature clump height of <6 inches.
   (While on my soapbox, I’ll complain that the American Hosta Growers Association has not standardized on specific mound height sizes for minis and other hostas, encouraging its members to utilize these designations uniformly and consistency in descriptions. I would think this would greatly assist the entire hosta nursery industry; it certainly would greatly assist gardeners.) 
   Then there are nurseries that entirely avoid the issue of what’s a mini size  by listing clump and leaf-blade length and width dimensions without defining size categories. The purchaser decides if the plant is a mini. Exemplary is Tony Avent’s Plant Delights Nursery, which describes hostas by clump height and width, sometimes carefully prefixed with “at least.”
   Since an AHS Hosta Show primarily features cut leaves, it naturally would follow that their classification is based on leaf blade dimensions. Obviously, a classification system based on clump height would be impractical, probably impossible. Only at AHS Region One’s highly regarded FIRST LOOK events are entire clumps judged. Most entries are new, unregistered seedlings and sports. Though preferred, entries do not need to be mature plants.

Clump Width?

   You might ask about clump width being a limiting size criterion. Although the height of mounds more-or-less usually maxes when the hosta develops maturity, clump width continues to increase with increasing years of growth. The classic example is H. venusta.  There are clumps estimated to be more than 20 years old that are greater than several feet in width yet, clump height remains about 4-5 inches.

Hosta Show’s <6 sq. in.

   The AHS Hosta Show classifies hostas according to registered leaf dimensions. Leaf blade dimensions in the official registrations are used to determine whether hostas are classified as mini, small, etc. The show’s definition of a mini hosta is: leaf blade area <6 square inches.
   Quickly let me say here that technically “<6 sq. in.” is not the same as “no greater than about 6 sq. in.” The former excludes leaf blade areas that are 6 sq. in.; the latter permits leaf blades areas that are 6 sq. in.
   In other words, if a hosta’s leaf blade length multiplied by its width is 6.0 sq. in. (or greater), it is not classified as a mini for AHS Hosta Shows. For registered hostas, Section V is the show’s mini category and all hostas in Section V have leaf blade areas 5.99 sq. in. and less. (That’s not 6.0 sq. in. but 5.99 sq. in.) Registered hostas with leaf blade areas of 6.0 sq. in. and greater are classified as small hostas, and are Section IV category. The size designation for Section IV is: leaf blade area of 6 to <30 square inches.
   You might better appreciate the importance of the left-pointing carat, <, prefixing 6 sq. in. with this example: For AHS Hosta Show classifications, a hosta with leaves 3.0 inches long by 2.0 inches wide is classified as a small hosta, while one with leaves 2.9 inches long by 2.0 inches wide is a mini hosta. Yes, this is “hair splitting” but there is a numerical divide.
   Now let’s be open (or transparent in today’s political jargon) about this: If anyone thinks that a leaf designated as 3.0 inches long is significantly – or even meaningfully – different from one designated as 2.9 inches long, he or she never has measured any hosta leaves. Or maybe he or she is “puffing the magic dragon.” However, there has to be some demarcation between mini and small, and the AHS Hosta Show’s system has worked O.K. for many years. It ain’t broken; no fix it needed. I advocate no change.
   Simply keep this in mind: All hostas classified as minis for AHS Hosta Shows comply with the 2010 AHS mini size criterion, but all AHS mini hostas may not comply with the AHS Hosta Show mini classification. I suspect it’s only a few. If they happen to be outstandingly significant in the world of hostas, they always can be treated as exceptions.

   It must be recognized and accepted that show classification folks cannot be expected to make pragmatic judgments on the correctness of dimensions recorded in registrations. They cannot be expected to change dimensions in the official registry. Nor can they be expected to use dimensional information from other resources. They are locked into what’s recorded in the registrations. Arithmetically, with consistency, they use the formula of leaf length × leaf width = leaf blade area: those with values of <6 sq. in. are mini hostas for AHS Hosta Shows.

'Baby Bunting'

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