When you’re planting bulbs this fall for spring color, consider the trees. Certain bulbs make better companions for trees than others, according to Julie Janoski, Plant Clinic manager at The Morton Arboretum.
Keep the big, brassy tulips and hyacinths out in full sun, away from the shade of a tree’s branches. What you need beneath a tree is a perennial plant that is relatively shade-tolerant and blooms early, before the tree unfolds all its leaves. Plant some of the early bloomers under trees since the leaves come out after the bloom. That gives each bulb plant time to get enough sunlight to recharge for next year before the deep shade comes.
Perennial bulbs don’t need to be replanted each year, and some will spread or even reseed if the conditions are right. That means that the tree’s roots will be disturbed only once, when you first plant.
It’s best if the bulbs themselves are small, so you can make a small hole to minimize the damage.
“The smaller the holes the better,” Janoski says.
Try a dibble–a pointed tool that makes a just-wide-enough hole.
Most of these bulbs have small flowers, so they need to be planted in groups of at least 30 to 50 to have much of a visual impact.
It’s easy to plant bulbs. The soil must be cool, so wait until after the first frost. Place the pointy end up (that’s the stem end). Dig a hole just three times as deep as the bulb is wide—so a one-inch-wide bulb needs a hole 3 inches deep. There’s no need to add fertilizer. Refill the hole, water the planted bulbs well, and spread mulch over the soil surface to insulate the soil and keep the bulbs from sprouting too early in a winter warm spell.
Shop dozens of bulbs for planting this season at The Arboretum's Annual Bulb Sale, going on now.
Here are four bulbs that are good companions for trees.
Siberian squill (Scilla siberica): Small banner-blue flowers in late March or early April often reseed, spreading to shady areas throughout the yard.
Winter aconite (Eranthis hyemalis): Looking like ground-hugging buttercups, the yellow blooms often appear as early as late February. The plant spread in clumps.
Snowdrops (Galanthus nivalis): Another late-winter bloomer, snowdrops have charming dangling white flowers. The plants multiply to form dense tufts.
Daffodils (Narcissus): Choose only early varieties, so they will get their blooming done before the trees unfurl their leaves to shade them.