Who is your competition in the local area?
How much money and shelf space do you have allocated for teas?
What product format are you looking for - teabags, looseleaf, or both?
As you will probably be buying wholesale, you will face minimum purchase limits that may well overwhelm your stocking budget.
You may want to query customers (do a small giveaway in return for them filling out a short questionaire) on their preferred flavors of tea, as you are more likely to sell these teas than looseleaf unflavored teas. You can ask them about their preferences among looseleaf (black, green, oolong), but don't be surprised if you have your work cutout for you, in one-on-one time in educating your customers to encourage sales in brewing and consuming unflavored, nonbagged teas, because of a lack of exposure and competition in beverage consumption preferences with flavored coffees and bottled cold name-brand cold drinks.
If you want boxes/tinned teas, stick to the well-known names, like Harney and Sons, Republic of Tea, at the middle price points, PG Tips, Twinings, and Scottish Blend at the lower price points. You can offer a selection of bagged and looseleaf teas to suit customer demand and your budget. If you want to try something out of the ordinary, contact Murchies Teas in Vancouver BC. You would be surprised at the number of Canadian expats that would flock to buy it locally. Ask first, though.
Since you're in Maryland, you have a relatively educated public with more sophisticated buying habits than, say out here in the sparsely populated wilds of the Inner Pacific Northwest. Consider your displays showing simple tea-brewing setups for work and home. Suggest better teabags for ease of use in the workplace or while away from home.
You can also cater to coffeehounds by carrying a nifty mate that tastes like coffee (Matte Latte, Republic of Tea).
Your aim is to encourage customers who are passingly familiar with tea to increase their tea consumption - hopefully, through your shop.
You should also talk candidly to national wholesale suppliers like Specialteas.com and Republic of Tea for recommendations on startup packages for small businesses. They can set up a progressive purchase plan, based on tea sales performance.