A carpet of Crocus tommasinianus. Once established, a colony spreads by self-seeding. (Hank Davis/Longwood Gardens)

I love spring bulbs for all sorts of reasons: because they are foolproof, because the autumn labor of sinking them in the ground is now forgotten, and because they offer the first cheerful proof that spring is afoot.

If you shift your bulb repertoire away from the brassy daffodils of late March and the chaliced tulips of April, you can revel in a bulb display for weeks before that elusive vernal equinox.

Many of these early birds are dainty, so you need to plant a lot of them, but what you give up in scale you gain in magical effect.

The Crocus chrysanthus variety Ard Schenk. (Hank Davis/Longwood Gardens)

In my garden in Northern Virginia, the crocuses began to open on Feb. 21, a full month before the official start of spring. The snowdrops started blooming before then, spurred no doubt by a ridiculously mild December. In other gardens, I saw long-blooming displays of winter aconite, essentially a jolly buttercup that is quite content to poke up between patches of snow. As with the crocus, it will slowly spread over many years as the ants and other insects carry the seed from the mother plants.

Winter aconite. (Glenn Kopp/Missouri Botanical Garden)

Some of these “bulbs” are botanically corms or tubers — horticulturists call the group geophytes — but they all share a need to be in the ground in the fall, so they can first send down roots and produce foliage.

When they are in a reasonably sunny, free-draining location, they will return year after year, and expand their numbers. The classic example of this is the Crocus tommasinianus — the “tommies” — which can seed themselves into an entire lawn once planted, to delightful effect. They have been flowering for a while. The more robust and colorful Dutch hybrid crocuses bloom a couple of weeks later.

After years of ignoring crocuses, I have gone to town with a mixture of species bulbs (C. tommasinianus, biflorus and chrysanthus) that are the epitome of cheap and cheerful. I think I paid under $50 for 500, and add that amount each year.

Crocus tomassinianus, known to gardeners as “tommies.” (Glenn Kopp/Missouri Botanical Garden)

The bulbous iris — Iris reticulata — started flowering at the end of February, and my various clumps return larger each year.

The daffodil nut can have flowers from February to May, if the volatile weather patterns cooperate, and some of the earliest common varieties include February Gold, Jetfire, Tete-a-Tete and the Tenby daffodil.

The earliest tulips to bloom are the ground-hugging wild tulips, and I am awaiting signs of a bunch I planted in the fall of Lilac Wonder, a variety of Tulipa bakeri and T. biflora. Apart from their eagerness to come back each spring, they are valued for the way their blossoms open to reveal pretty contrasting colors. The biflora, for example, is white but presents a large yellow heart. It is also fragrant and sure to be a magnet for the first bees of the season, buzzing around for some pollen and nectar.

If you want a sense of how moving and romantic these lesser known spring bulbs can be, get over to the garden at Dumbarton Oaks this month, where Siberian scilla, winter aconites and crocuses can be found in such places as the Beech Terrace or below the Lover’s Lane Pool in Melisande’s Allee. Later this month, glory-of-the-snow and snakeshead fritillaries will prolong the display.

Another place to see bulbs in March is Longwood Gardens, in Kennett Square, Pa., where gardeners have been planting prodigiously in recent years to bring forward the spring bulb display. They added half a million bulbs last year alone to seven areas of the gardens, including Peirce’s Park and Oak Knoll.

The glory-of-the-snow blooms later in the month, with purple-blue blossoms that point skyward. This is the species Chionodoxa forbesii planted on Oak and Conifer Knoll at Longwood Gardens. (Colin McCallum-Cook/Longwood Gardens)

Mark your calendar for next September, order extravagantly from the mail-order bulb merchants, and set aside a couple of weekends in October to plant your own early spring.