Magnolias are wonderful small trees or shrubs, which despite their southern connections, can work as spring-flowering plants for gardens in USDA Zone 4 — about the southern half of Minnesota, as well as areas along Lake Superior. The Minnesota Landscape Arboretum has a fine collection of magnolias and they are blooming right now.
Magnolias for the north include hybrids of Magnolia stellata and Magnolia kobus as well as the native cucumber tree (Magnolia acuminata). Most cultivars are small trees or shrubs, ranging from 10 to 25 feet tall with a vase-shaped form. The cucumber tree, however, grows up to 80 feet tall, and is grown primarily for its qualities as a sturdy landscape tree. (More varieties of hardy magnolias are being developed, too. Northern Gardener covered the work of Green Bay-based breeder Dennis Ledvina in our March/April 2013 issue.)
Magnolias bloom in early spring, generally from late April through mid May in the Twin Cities. The flowers appear before the leaves on the plant, and the plant can be covered with blooms in shade of cream, pink or yellow. Magnolias are natives of forest clearings, so they can handle light or dappled shade but they bloom best in full sun. They need moisture (but not too much) and prefer a slightly acidic soil. Many people plant their magnolias near the house to protect them from the wind. Avoid the south side, however, as you do not want the plant to come into bloom too early. The magnolia root system is fibrous and shallow, so dig a wide hole when planting magnolias and spread them out. A yearly application of a balanced fertilizer or mulching with compost will help feed the plant. Magnolias look stunning surrounded by early spring bulbs, such as squill, and they do well with a shallow-rooted groundcover for a neighbor.
Here are some of the best varieties for Minnesota:
‘Royal Star’ Bright white blooms, fragrant, this plant grows only 15 feet tall at the most and blooms early in the season.
‘Ann’ For a cloud of pretty pink blooms, plant ‘Ann’. This one will grow to 30 feet tall. It can be prone to scale and other pests or diseases.
‘Jane’ With pinkish purple blooms, this later blooming variety should not be planted too close to the house.
‘Leonard Messel’ With narrow star-shaped petals that are white on one side and pink on the other, ‘Leonard Messel’ is a popular magnolia in Minnesota. Some sources rate it as zone 5, so choose a protected location.
‘Merrill’ Another magnolia with cream-colored blooms, ‘Merrill’ is known for its hardiness. A good choice for Minnesota.
Do you have magnolias in your yard?