Hostas can spread, either through underground runners or seeds. Rhizomatous Hostas that spread underneath the soil are the worst offenders. These varieties will spread almost indefinitely. Non-Rhizomatous varieties will grow in clumps that reach a mature width.
Yes, hostas are capable of self-seeding, provided the right environment exists. However, not all hosta cultivars are fertile. Some of them may not produce viable seeds. Also, the resulting hostas may or may not end up resembling the parent plant.
'Sum and Substance' is an immense hosta growing to 30" high and 60" in diameter. Features large (20" x 15"), heart-shaped, thick-textured, glossy yellow leaves which turn golden over time with proper sun exposure and racemes of bell-shaped, fragrant, white flowers on scapes up to 38".
The Sum and Substance Hosta is unique when compared to its other family members. ... Additionally, this Hosta has a unique green to yellow color to its leaves and can even do well in Full Sun, as opposed to many of the other Hostas.. . . . .364011234050!]0000000000000009783314147714!]