Morel mushrooms (Morchella species) are a prized delicacy, signaling the arrival of spring for foragers across North America. Characterized by their unique, deeply pitted caps, these fungi appear for only a few weeks each year. The pursuit of this edible mushroom, sometimes called the “sponge mushroom” or “hickory chicken,” is an annual tradition for thousands in Wisconsin. Success requires understanding local conditions and specific ecological cues in the state’s woodlands.
Tracking the Seasonal Start
The appearance of morels in Wisconsin is not tied to a specific date but rather to environmental indicators that typically align with late April through the end of May. The season progresses from the south toward the north, with the peak often occurring around the middle of May. Predicting the exact start requires monitoring soil warmth, which is the most reliable predictor of when the mushrooms will fruit.
Morels generally begin to emerge when the soil temperature consistently reaches the low to mid-50s Fahrenheit (50 to 53°F is optimal). This warming must be sustained, often requiring nighttime air temperatures to remain above 40°F for several consecutive days. A traditional visual cue used by seasoned foragers is the size of oak leaves, which should resemble the ear of a mouse when the season is beginning.
Where to Search in Wisconsin
Morel mushrooms are typically found in association with specific tree species that provide the necessary nutrients and conditions for their growth in Wisconsin’s forests.
Indicator Trees
The most famous indicator tree is the dead or dying American elm, where morels often appear near the base as the bark begins to peel away. The fungus thrives on the dying root systems of these trees, which have been devastated by Dutch elm disease. Other productive locations include areas around dead or declining ash trees, particularly since the arrival of the emerald ash borer, and older, unmanaged apple orchards. Stands of poplar or aspen are also known to host morels, particularly the black morel species, which tends to emerge slightly earlier in the season.
Prime Locations and Regulations
Foragers often report high success rates in the southwestern portion of the state, known as the Driftless Area, where spring conditions arrive sooner. Foraging on public land, such as state forests and county parks, is generally permitted for personal use, but foragers must first check specific local regulations. Identifying the specific tree species and understanding the general soil conditions—well-drained and often sandy—will increase the chances of a successful hunt. It is considered good foraging etiquette to not harvest all the mushrooms in a single patch, ensuring the survival of the patch for future seasons.
Distinguishing True Morels from Look-Alikes
Foraging for morels requires careful identification to avoid consuming toxic look-alikes, primarily species in the Gyromitra and Verpa genera, sometimes called “false morels.” The definitive test for a true morel (Morchella) is that the mushroom is completely hollow from the tip of the cap down through the stem. When sliced lengthwise, the interior should be a single, uninterrupted chamber with no cottony material or internal partitions.
True morels possess a cap covered in distinctive pits and ridges, giving it a honeycomb or sponge-like appearance, and the base of the cap is fully attached to the stem. False morels often have a cap that is more wrinkled, lobed, or brain-like, lacking the distinct pitted structure. Their stem is typically filled with a cottony substance or has several chambered sections. Many false morels contain gyromitrin, a compound that metabolizes into a potent toxin, making this visual and structural differentiation a matter of safety.