New hosta cultivars are being introduced all the time. Basically, they come from one of two sources. Many are hybrids which are the result of the combination of genetic materials through sexual reproduction i.e. seeds. Either by nature (bees) or through the efforts of hybridizers (humans), pollen is applied to the pistil resulting in seeds that carry a new combination of genetic information.

The other major source is through what are called "sports". For a variety of reasons, hostas will generate new buds that produce divisions that have different characteristics from the rest of the mother plant. This is how many (but not all) of the valued variegated cultivars have their origins.

In the distant past, all sports occurred spontaneously in the garden or nursery. "Sport fishing" which involved finding these new hostas was a common activity. In recent decades, tissue culture (TC) propagation has resulted in a huge increase of sports from which to choose special plants for introduction. TC produces large numbers of clones in a short period of time plus certain growth hormones and other chemicals used in the process also trigger a higher than usual occurrence of sports.

Certain species or cultivars have proven to be especially prolific in producing either seedlings or sports or both. These plants show up in the ancestry of a large number of new hosta cultivars.

Listed in alphabetical order are some of the species or cultivars that have played a role in developing several new cultivars introduced in the past few decades. Also included are plants of uncertain background which are considered a particular "type". For instance, many large size blue-green hostas are considered "H. 'Sieboldiana' -type" even if their exact heritage has not been documented.

[**As always, these lists comprise a representative sample but do not by any means include all hostas used in developing new cultivars.]