NyxOfTheFallen said:You have to wait for rose hips, the fruit to form and then cold stratify them for two months and the roses won't be true to seed.
You don't need to stratify most warm climate roses or most moderns (due to china rose influences). They'll germinate under 15c/59f within a few weeks in most cases.
If Lady Banks is R. Banksia it won't need stratification, it's from a temperate region (stratification is more for older european and some native north american species from regions where it snows, it's just to trick the seed in to thinking it's been through snow and snow is over so it's safe to grow)....most reblooming rose species (and hybrids involving them) are from area's without snow or freezing so will germinate straight from the hip. R. Banksia also likely wont set hips by itself as many diploid roses have some degree of self sterility and the roses in commerce are likely all the same clone. If you manually pollinate with other roses though (like diploid china roses) you'll get some hip set and seed if the other rose is compatible but they'll be hybrids.