Typically, hops growers don't set their crops to seed. To let the hops go to seed halts the growth of the flowers (the part we brew with) as the plants put all their energies into seed production at that point. What's cool about hops is that they are keen on sending out runners just under the ground. These are called Rhyzomes, and they produce daughter plants off of the central crown of the hops.
There are hops growers that sell whole crowns and there are hops growers that sell just the rhyzome. Harvests of rhyzomes usually come during the spring months (March/April) and the ideal time to plant them is after your last danger of frost has passed. I'm guessing in Maryland, that's usually around May 1st. As to which to buy (rhyzome or whole crowns), it depends on what variety you'd like to grow and what's available for purchase and planting at the time. I prefer whole crowns as they're more mature plants with an established root mass and tend to produce hops in their first year. Rhyzomes look like a little dirty stick and they usually need one season to fully mature below ground before producing a sizeable hops crop.
Maryland gets a little warm in the summer, and hops aren't fans of heat. I should know because I live in Florida and have struggled with my hops down here. I would pick a location that gets a brief amount of direct sun every day, say 4-5 hours (morning is best) and then indirect sunlight the rest of the day. Plant them with a good organic fertilizer mix into your soil and space them out at least five feet apart. You will also need to train the hops bines to grow up (or around) something as they are climbers. Strong hemp twine or tall sections of lattice fence work well for this.
Hops need moisture, but they also need good drainage. In the summer, you will be watering them almost daily. The main reason mine have struggled so much is I can't keep up with their watering demands due to vacations, daily distractions, etc.. Mine have completely dried out and shriveled up to nothing three times this summer, only to spring right back into rapid green growth when the rains hit or when I start watering again. This means they are resilient, but fragile to heat. I'm going to let mine overwinter and hook up a passive watering system using a rain barrel and some drip tubing, so they can take as much water as they need next year.
As far as which varieties to grow, it's up to you. Growers generally recommend going with the "C" hops (citra, cascade, chinook, etc.) but i've had just as vigorous of growth, if not moreso, with my fuggles freebie plant my hops grower sent to me.
