Daffodils, tulips, and other flowering bulbs are the glory of spring. Once their flowers fade, though, don’t be too quick to cut the plants back, says Doris Taylor, Plant Clinic manager at The Morton Arboretum. They need their leaves now in order to flower next year.
Perennial bulb plants use their leaves to collect energy from sunlight, she says, so they can build next year’s flower and its food supply, packaged in an underground bulb.
“At this time of year, they need all the energy they can get,” Taylor says.
Don’t braid or tie up the bulb plants’ leaves either, she says. That reduces the surface area available to gather sunlight. You can go ahead and cut back the flower stalk, but leave the foliage alone.
Many kinds of bulb plants can flower for many years in the garden. That’s one reason they are good companions for trees: If you plant bulbs around a tree once, you can have spring flowers every year without repeatedly disturbing the tree’s roots for planting.
However, you need to let the leaves alone each spring until the plants have done their work.
“Wait until the leaves start to turn yellow and die back naturally, which can take several weeks,” Taylor says. The yellowing leaves are a signal that the plant has finished developing a flower and is going dormant for the summer.
“At that point, the plant doesn’t need its leaves anymore,” she says.