Morel mushrooms, at least here in Minnesota where I am based out of, are the golden child of wild harvested mushrooms. Aside from truffles, they are placed on a pedestal over all others, except for the occasional folks who value porcini or matsutake more highly. To most, the morel is the end all be all--and that is definitely the case in the midwest.
This prized mushroom leads one to the next big question: how do you find them? First, you need to know when to start, which will be the focus of this post. Second, where to look (read my post on elms to learn more about that). Lastly, you'll need to know how to identify the morel and make sure it's what you're after, which you can learn more about here. But first, when to start looking. The answer is very simple. Through winter, the soil freezes; gradually in the spring it thaws and begins to warm up. When the soil temperature about four inches deep has been at or above 50 degrees Fahrenheit for a few days, the morels should begin fruiting nearby trees with which it has a mycorrhizal relationship.
This is probably the worst answer. Yes, it is very specific, but at the same time, it's kind of vague. For example, if I go outside into the backyard of my house in Northeast Minneapolis and check the soil temperature and find that it is 50 degrees F does that mean I can go out into the woods and find them growing everywhere? Not likely. There's two reasons for that: obviously habitat is a big one, which is something I'll discuss in another post (check out: trees, morels, mycorrhizal symbiosis, and forests), but the other reason is something I like to call microclimates.
In Minneapolis, we are on something called an "urban heat island". These areas are warmer due to the mass of concrete and other human made structures which absorb heat more readily than, say, a forest. Also, forests are often tucked into valleys or in a dense network of trees which block the sunlight which causes the soil to heat up more slowly. On the other hand a south-facing slope (note that the Sun, at least in Minnesota's neck of the woods) shines from the south. This means that hills, particularly bare ones with nothing to block the sun, will heat up much faster than other soils. Often they will be a full ten to even twenty degrees warmer than north facing slopes or spots deep in valleys. Those south facing slopes will be good "early season" morel spots, while north facing slopes and ravines are good "late season" spots.
Let's get down to the nitty gritty here, as I realize I am rambling. What are, aside from soil temps, some signs from God, so to speak, that morels are likely growing out there in the wilderness somewhere? One of the most sure-fire signs that all the old timers will say--that is most definitely true--is that when the lilacs (syringa vulgaris left hand photo below)
are in full bloom, the morels are out. This is a great indicator. It's the "classic" sign.
On the other hand, it seems that it indicates peak morel season. Once lilacs are in full bloom, there's often only a week or two left before the remaining morels are eaten out by worms, water logged and moldy, or just picked by someone else. I have personally found you can often find morels before the lilacs are in full bloom, and given that the morel season is so short (two to four weeks), it's important to maximize your time hunting.
So a few other signs that I have noticed are when red buds (cercis canadensis-right hand photo) are in bloom (which is a little sooner than the lilacs), you can find them. If we have a week or longer of warm weather with highs in the 60's and lows in the forties and it's end of April or early May then it's time to get out looking. It used to be that really, in Minnesota, you would never look for morels before May, but with climate change it seems to be more frequent that morels will start to fruit in in the latter days of April.
Once you're actually out in the woods looking around, you should see a few things: that pale green shimmer of fresh buds all over the landscape (aspens, elms and some maples will be fully leafed out, with oaks showing buds ready to pop), Jack in the pulpits (arisaema triphyllum) should be fully erect, Catchweed aka cleavers (galium aparine) should be large enough that each little lancing leaf should be about an inch and a half (left hand picture, which also shows how well grey morels can blend in to twigs and leaf litter), and ramps, where applicable, should be prolific.
If you are in an area where you are seeing really small cleavers or you see some jack in the pulpits that just look like stems that haven't opened, I would go somewhere else. With morels, to be successful, you have to move around a lot until you see the right signs. Then you want to slow way down. Good luck out there, folks and happy hunting!