Thanks for the question! its good to hear that your gramma's hollyhocks are alive and well.

Hollyhocks are biennials. This means that the first year they grow a rosette of leaves. The second year they bloom and set seed. They will cross-pollinate so the new hollyhocks will not look just like their parent plant. 

Many hollyhock seeds sold today are hybrids so you get what the package says during their second year, but the seeds will produce plants with different colors. 

Have fun with them. they are a beautiful addition to any garden.

https://extension.illinois.edu/blogs/good-growing/2023-05-26-how-grow-and-care-hollyhocks



That is the million dollar question and the answer is not easy. 

When we talk about seed viability we are talking about seed that is harvested at the optimal time, stored in optimal conditions and then planted at the correct time under the best conditions. None of these things apply to seed dropped outside from the plant. 

We know that some seeds will not survive Minnesota winters. Hollyhocks often do but that is generally during a ‘normal’ winter with good snowfall prior to deep cold. Seeds get eaten by critters, rot from soil that is too wet for long periods, dry out during a drought year. Some seeds need to be stratified by microbes or birds in order to germinate. Some need to ferment. 

It is likely that your gramma’s hollyhocks just sat there in the soil during our drought years. This year we have had more rain and so now they have germinated. 

There are no legal standards for flower seeds but most charts say 2-3 years storage for Hollyhocks. That simply means that after that time, germination rates drop each year. There were perhaps hundreds of seed from in your garden and now some of them have germinated. It’s also possible that these were dropped by birds.