There’s no more satisfying way to spend a crisp fall day than planting bulbs for spring bloom. “It’s an investment in beauty,” said Michael Jesiolowski, manager of the Plant Clinic at The Morton Arboretum in Lisle.
Bulbs such as tulips, daffodils, crocuses and hyacinths are planted in autumn so they’ll be ready to bloom in April and May. “They need time in the fall to grow roots and time in the winter to chill in cold soil,” he said.
A bulb is a fully equipped bloom package. Inside is a partly developed but dormant plant, including stems, leaves, and flower buds, along with a food supply. After it spends about three to four months in cold soil, moisture and increasing warmth will signal the plant to emerge, seek its way to the surface, sprout and bloom.
Many kinds of bulb plants, such as daffodils, scilla, and snowdrops, will return to bloom every year, building a new bulb each summer after their spring bloom is done. “If the plant is well suited to its site and it’s happy, it’s more likely to come back,” Jesiolowski said. “Daffodils often last for decades.”
Here are some tips from the Plant Clinic for success with spring bulbs.
Plant at the right time: Get bulbs in the ground by the end of October so they have time to establish themselves with some roots before the soil freezes.
Choose the right kind of bulb for your site: The most popular bulbs, such as tulips, daffodils, and hyacinths, need full sun. “If your yard has trees that cast shade, you can still enjoy some kinds of bulbs if you plant early-blooming species,” he said. “They’ll have time to flower in the sunlight that reaches the ground before the trees leaf out.” Bulbs that do well in shadier areas include snowdrops, winter aconite, and Grecian windflower.
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Provide well-drained soil: If your soil is dense and poorly drained, like the clay soils common in the Chicago region, it may help to dig compost or other organic matter into the planting bed before digging holes for bulbs. Daffodils, alliums, crocuses and snowdrops are somewhat more tolerant of clay soil than other bulbs.
Buy plenty: “Even the most gorgeous double tulip won’t make much of a show all by itself, much less a little tiny crocus,” Jesiolowski said. “Plant bulbs in groups and masses so they really have an impact.”
Extend the flower show: Plant a range of species to enjoy spring bloom longer. Snowdrops sometimes bloom as early as late February, and some alliums don’t open until late May or June. There also are early, late and mid-season varieties of tulips and daffodils.
Plant deeply: The rule of thumb is to dig a hole three times as deep as the bulb is tall. A bulb covered by plenty of soil is protected, so it’s less likely to be warmed up and tricked out of dormancy by a brief late winter warm spell. “Coming out of dormancy too soon is the biggest danger for bulbs,” he said. Use a long, slender trowel to dig a single-occupancy hole, or dig a wide hole to plant a group of bulbs.
Put the pointy end up: Many bulbs, like those of daffodils and tulips, have a flattish end where the roots grow and a more pointed end where the stem and flower will sprout. Place the bulb in the hole with the flat (root) side down and the pointy (stem) end up. Other bulbs are more cryptically shaped. If you can’t tell which is the stem end, place the bulb on its side and trust the plant to figure it out.
Skip the fertilizer: A bulb contains all the food the plant needs, so there’s no need to add bulb fertilizer or bone meal when you plant.
Water and mulch: After you fill the hole, water the planting area generously, and then spread a 1- to 2-inch layer of mulch. The insulation of the mulch will help keep the bulbs dormant during those treacherous warm spells in late winter and early spring.
In March or April, after a weary winter, you may see a few green sprouts, and remember your day planting bulbs in October. “When those sprouts bloom, that’s the payoff,” Jesiolowski said.
For tree and plant advice, contact the Plant Clinic at The Morton Arboretum (630-719-2424, mortonarb.org/plant-clinic, or [email protected]). Beth Botts is a staff writer at the Arboretum.