Hardiness zone 5 has a minimum annual temperature of -20 to -10 degrees Fahrenheit, and flowering trees for this zone include the Eastern Redbud, the Japanese Yoshino Cherry, the Red and White Dogwood and the Saucer magnolia.
The flowers of the Saucer Magnolia, or Magnolia x Soulangeana, appear early in the spring, and the flowers can range from white to pink and purple. They are best transplanted in early spring and thrive in rich, moist, loamy, acid soils. Ideally, they should be planted near other trees where they can be protected. The tree itself can grow from 20 to 25 feet tall.
The Eastern Redbud is one of the first trees to bloom. Unlike the Magnolia, which may take three or four years to bloom, the Redbud blooms when it is young. The tree can grow between 20 and 30 feet tall and have a 25 to 35 foot spread. The trunk often begins to divide close to the ground. The flower buds of the Eastern Redbud are purple and open into pink flowers. The Redbud tree can tolerate most types of soil as long as they're well-drained. The tree does well in a woodland garden or in full sun. Redbud trees usually don't live longer than 15 years.