We gardeners know when spring arrives. It’s certainly not by the date on the calendar. The signs are all around us – blooming daffodils, forsythia, Bradford pears and saucer magnolias. But all these plants are visitors to our American gardens from Europe and Asia. The real question is: Can these foreigners to be trusted to decide when winter has passed and another gardening season has commenced?

Common Serviceberry

Common serviceberry is widely distributed across the eastern US and is one of our first native trees to bloom.

Photo Credit: Gerald Klingaman

Saskatoon Berry

Saskatoon serviceberries are great for pies, jellies or just eating fresh from the tree!

Photo Credit: Gerald Klingaman

Flowers Up Close

The trees white blooms are quite stunning up close.

Photo Credit: Gerald Klingaman

Amelanchier Canadensis

Amelanchier canadensis can be found from Canada to Alabama along the Appalachian chain.

Photo Credit: Gerald Klingaman

While these settlers sure are close to predicting real spring, I’ve logged blooming dates – albeit in a haphazard fashion – of some of the common landscape plants in my four decades of gardening. And while the arrival of “blooming” spring may change a bit, one of our great native trees – the serviceberry (Amelanchier) – often disagrees with these immigrants about when spring really arrives.

You can find serviceberries in every state except Hawaii, and there are about 20 species described. They go by a bewildering array of common names that are often associated linguistically with our early American roots. Probably the best common name for the group is serviceberry, but they’re also called sarvice, juneberry, shadbush, shadblow, Saskatoon berry – and probably a variety of others.

The most common and widely distributed species in the eastern states is Amelanchier arborea. Known as common serviceberry, this 25-foot-tall deciduous tree produces an abundance of five-petaled white blooms in terminal clusters. It occurs as a scattered tree in the woods from Texas to Quebec, Canada, and all points between. It’s an understory tree, often found in higher, cooler, better-drained sites than where dogwood or redbud would grow. Over my years of observation, I’ve found this serviceberry to be one of the most erratic plants with regard to bloom date, but it’s one of the most reliable predictors of true spring.

Another widely distributed species is Amelanchier alnifolia, the Saskatoon serviceberry, which ranges from British Columbia to New Brunswick in Canada and throughout the mountains of the western US. It’s more shrubby than treelike, but it’s important because commercial fruit-producing selections have been made from this species. In parts of Canada, Saskatoon serviceberry is a significant garden plant. Amelanchier laevis (Allegheny serviceberry) and Amelanchier canadensis (thicket or Canadian serviceberry) are two more lovely species, and they’re widely distributed from Canada to Alabama along the Appalachian chain.

Now, there’s a real key to spring-blooming woody plants and their ability to predict spring. You see, these plants develop their flower buds in fall, but the flowers remain dormant until they have the proper chilling times. (Orchardists, primarily working with apples and peaches, have developed models to determine when particular fruit cultivars will bloom based on the concept of accumulation of “chill hours.”) The optimum temperature for accumulating chill hours to break flower bud dormancy lies between 35-45 degrees F. When the temperature falls below freezing or above 55 degrees F, no chill hours are accumulated. For temperatures that are less than optimum but below 55 degrees F and above freezing, hours accumulate at half the rate of the optimum range. Once the required number of chill hours is accumulated, blooming starts – as long as the weather is warm enough for flower buds to grow.

Some spring bloomers need fewer chill hours. For example, forsythia requires about 800 hours, while Bradford pear requires about 900 hours. But common serviceberry needs about 1,000 chill hours to bloom. If it gets the right amount of cold, the blooms appear very quickly. If it hasn’t had enough chilling, the tree will still flower, but the blooms will be slow to appear.

Hardy from USDA hardiness zones 4-9, serviceberry makes an excellent choice for spots where you might need a small specimen tree in your garden – just be sure to plant it where you can enjoy the white spring blooms, fruit and fall color. (Note: Saskatoon serviceberry is hardy only from zones 4-6, and it’s not well-suited to locations with hot summers.) The trees will bloom in some shade, so they’re also a good choice for gardeners with tree-covered lots.

Give your serviceberry a woodsy, organic soil mix. Once established, the tree will tolerate drought, but it does best when given a location with moist summertime conditions. These trees are slower to establish landscape significance than dogwoods or redbuds, but once established they do have a longer life in the garden. While they’re not susceptible to any serious insect or disease pests, poor drainage, planting in heavy clay soil or overly droughty conditions can cause plant loss.

If you’ve got any doubts as to when spring hits in your neck of the woods, then get your garden a serviceberry. Not only does this hardy beauty offer something to look at every season, it’s a surefire way to learn when to kick off your gardening season – the native way!