Answer: Unfortunately, all trees including evergreens will drop leaves seasonally. Among the many trees which attain a medium size and offer summer shade I would consider 'Drake' Elm (Ulmus parvifolia 'Drake'), Cedar Elm (Ulmus crassifolia), and Chinese Pistache (Pistacia chinensis).
No matter what you plant, plan on providing ample water during the first few growing seasons to encourage rapid establishment and good coverage of the alloted area. Check with a local nursery professional for additional suggestions and information on availability.
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