Know Your Trees

Tree identification is both practical and fun, but with 52 species in Minnesota and dozens of introduced varieties, learning to identify trees might feel overwhelming. To get started, here’s information on three trees commonly found in Minnetonka. All three reach a similar height of 50 feet or more, but can be distinguished by their leaves, fruit (seeds) and bark.

American elm The iconic, vase-shaped shade tree that once arched gracefully over many city streets. Characteristics: Leaf has a double-toothed edge, pointed tip and uniquely uneven base Greenish-yellow flowers bloom in early spring “Winged,” wafer-shaped fruits blow off the tree in June Autumn foliage is yellow Bark has a spongy texture Dutch elm disease (DED) was introduced from Eurasia in the 1930s, and it devastated community forests overplanted with these beautiful trees. DED is an ongoing problem, but resistant elm varieties are now available and chemical injections can protect mature trees.

Green ash Widely planted along streets and in yards as a replacement for elms. Characteristics: Leaf contains 3-7 lance-shaped leaflets, each edged with tiny teeth Green flowers bloom before the leaves emerge Clusters of slender, yellowish fruits mature in autumn Autumn foliage is yellow Bark has diamond-shaped “valleys” between flat-topped ridges Green ash thrives in many landscape conditions and is great for climbing. Ash trees also provide food and shelter for wildlife and are commercially important to the wood products industry. Unfortunately, emerald ash borer (EAB) has the potential to kill millions of ash in Minnesota. The best way to prepare for EAB’s inevitable arrival in Minnetonka is to identify ash trees and plan to treat or replace.

Red oaks Long-lived trees prized by people and wildlife; their care and maintenance is important to the community forest. Characteristics: Leaf has U-shaped indentations that cut toward the central vein Leaf lobes (“fingers”) are pointed Red or yellowish-brown autumn foliage turns brown and stays through winter Acorns have flat caps and take two years to mature Bark is marked with long, silvery streaks (“ski tracks”) Red oaks are used to make furniture, cabinets, flooring and more. Cavities inside red oaks are ideal nest sites for wildlife, and many creatures feed on the acorns. Red oaks are vulnerable to oak wilt fungus, which kills infected trees within weeks. Knowing the red oaks on your property makes it easier to protect healthy trees if oak wilt occurs nearby.

Learn More

These additional resources can help you learn more about trees in your landscape:

• Minnesota Trees, by David M. Rathke, is a useful and portable field guide published by the University of Minnesota Extension Service.
• Leafsnap is an electronic field guide with high-resolution photos for easier field identification, available online or download the free iPhone/iPad app.  
• “Trees with Don Leopold” is a series of short YouTube videos, organized by tree species.
• “What’s wrong with my plant?” from the University of Minnesota uses common symptoms to help you identify tree diseases.

Upcoming Events

Volunteer Buckthorn Cutting at the Ann Cullen Smith Property

Saturday, March 17 | 9:30 a.m.-noon
2510 Oakland Road (no building or posted address)

Restoration has begun on the 30-acre site donated to the city by Ann Cullen Smith in 2015. Help cut buckthorn under the direction of Minnetonka Restoration Specialist Janet Van Sloun. Registration is required in case of inclement weather; call 952-988-8400 or visit eminnetonka.com/NRevents. Additional information (including a map and parking instructions) will be emailed prior to the event.

Visit eminnetonka.com for city news and events.