The relatively cool but mild winters in Baltimore are well suited to the dormancy needs of apple trees, but the humid summers along Chesapeake Bay can make apple growing a challenge. According to the U.S. Department of Agriculture's climate map, expect winter low temps to drop annually to zero to 5 degrees in Baltimore.
According to the Maryland Apple Promotion Board, many apple varieties are grown in the state. The board's lists Empire, Fuji, Jonathan, Golden Delicious, Red Delicious, Stayman (Winesap), York, Gala, Mutsu (Crispin), Jonagold, Ginger Gold, and Rome varieties. The Maryland Cooperative Extension also mentions Redfree, Liberty, Freedom, MacFree, Enterprise and Goldrush varieties.
Wherever you garden in Baltimore, you'll need to consider proper site selection and other requirements to grow an apple tree successfully. Plant the tree where it will receive no less than eight hours of sunshine daily. Plant it in a deep, fertile soil that is crumbly in texture, rich in organic matter and able to drain well after rain or irrigation. According to the "Sunset National Gardening Book," while any apple fruits are developing, monitor the soil and keep it moist when rains are lacking, to prevent abortion of the young apples. More than one apple tree in the garden tends to increase the amount of flower pollination, which leads to more fruit.
Standard apple trees grow to about the size of small shade trees, 20 to 30 feet tall and 15 to 25 feet wide. For Baltimore's urban and suburban properties, choose varieties that are grafted on dwarfing rootstocks. These are labeled "dwarf" apple trees at a garden center.
Because of Baltimore's summer heat and humidity, you'll need to take extra steps with your apple trees. When choosing an apple variety at the garden center, select one that can resist a wide array of diseases, especially fireblight, apple scab, cedar-apple rust and powdery mildew. Many insect pests, including apple maggots and codling moths, act in unison with various diseases against the tree's ability to produce fruit. You may need to apply insecticides or other chemicals.
Contact the Howard County office of the University of Maryland's Cooperative Extension for recommendations or discussion of issues affecting apple trees:
Home and Garden Information Center
12005 Homewood Road
Ellicott City, MD 21042
Visiting a local garden center that sells fruit trees will expose you to apple tree varieties recommended by local horticulturists. The staff can answer questions about specific varieties for your Baltimore apple orchard.