How can I buy red cabbage plants for my mom's birthday?

Thanks in advance to anybody with advice!

My parents and I live near Chicago. My mom and dad have been very into gardening together the last several years. However, my mom had major surgery in December that kept them from seeding very much this year. Her birthday is coming up, and I know one plant they have been thrilled with is red cabbage. The last couple years, my mom has grown, pickled, and jarred a ton of red cabbage and it was a delight for my parents all winter long. This year, they let me know red cabbage was not one of the few they had time and energy to seed.

So my question is this: at this point (end of March near Chicago), what is the best way for me to buy cabbage plants for my mom to get to have this season? It's my understanding it's probably too late to start from seeds, but I am just having no luck looking for young cabbage plants that are ready to be put in the ground. I do not have any gardening experience myself, so I don't know what type of store to even look for, and I have not found any online services that would deliver the type of plant I'm looking for. If any of you hobbyists and experts have any advice or know of any great sources, I would be very grateful for your advice! I am willing to drive somewhere in the Chicagoland area, scour the internet as needed, or order them for delivery - just let me know what may be my best shot to come through for my mom's birthday.