More than once, I have had people visit my garden and be astonished at the size of a specimen of H. 'Sum and Substance'. Invariably they would ask, "What do you feed it to make it so big?" Well, that question tells me two things about the questioner.

One is that they don't know that we do not "feed" plants the way we would feed a pet dog or a pig. Plants feed themselves through photosynthesis and use nutrients as part of the building blocks along with water, light, chlorophyll, carbon dioxide and the proper temperature. Without an adequate level of all of these factors, the plant will not grow no matter how much fertilizer you apply.

The second thing it tells me is that they are not aware that there are different size hostas. H. 'Sum and Substance' grows that large because that is how big it is supposed to be based on its genetic makeup. That is why it is classified as a Giant size hosta.

For registration purposes, there are currently 5 size categories including Giant, Large, Medium, Small and Miniature. Until fairly recently, there was also a Dwarf category but that has been dropped. The measurements that determine which category applies include the width and height of a mature clump i.e. generally 5 to 6 years of age.

Mr. PGC Comment: This is the standard set by The American Hosta Society registration form. However, the glossary of the AHS website also includes a measurement for leaf area in square inches as part of the delineation.

The American Hosta Growers Association is in the process of updating the specifications that relate to the various size classifications. Once these are finalized and are adopted, they will become the official size categories for The American Hosta Society. For now, these are the guidelines for size categories:

Of course, just like all of the other measurement dependent traits listed about hostas, they may vary considerably depending on the age of the clump, growing environment, etc. In his vast experience with hostas, Mark Zilis reported at the 2010 Hosta Scientific Meeting that the tallest hosta he has measured was a specimen of H. 'Sum and Substance' which was 48 inches tall. A plant of H. 'Solar Flare' that he encountered had a clump 10 feet wide while an H. 'Empress Wu" leaf measured 22.75 inches long with a surface area of 339 square inches. Those are whopper plants which have probably been growing undisturbed for decades.

1. Giant Hostas - These largest of all hostas are used primarily as specimen type plants or plain colored ones may be used as background in mass plantings.  They have a leaf area of greater than 144 square inches and reach heights that exceed 28 inches.

 

2. Large Hostas - These size plants can also be used as a specimen or as the centerpiece of an arrangement in the garden. Variegated large size plants often work best in this role. A large hosta plant will have a leaf area greater than 81 and less than 144 square inches and reach a height between 18 and 28 inches.

 

3. Medium Hostas - Although rarely used as specimens plants, medium size hostas work well in a support role in groupings of hostas. They can be used to carry on the colors from the larger plants in an arrangement. Plants in this size group will have a leaf surface area of greater than 25 but less than 81 square inches and height of more than 10 but less than 18 inches.

 

4. Small Hostas - Small sized hostas are often used for the front of the border or for edging plants. Since many in this category spread by rhizomes, they are also used as groundcovers. In my opinion, I don't think you can beat the classic small cultivar, H. 'Golden Tiara' for these roles.

 

5. Miniature Hostas - The smallest category of hostas is miniature. These tiny specimens need to be used carefully or they will be overwhelmed by surrounding plants. Due to their size, many of these cultivars display best in containers with other dwarf plants. They may also be more sensitive to environmental issues such as drought or poor drainage and may need special care if they are to thrive in the garden.

These tiny plants have a leaf area of greater than 2 and less than 6 square inches and a height of only greater than 4 but less than 6 inches. More on the origin of miniature hostas...

Mr. PGC Comment: We will cover the design uses of various types of hostas in more detail in the next eBook of this series, A Rookie's Guide to Landscaping with Hostas.