Heather N. Kolich, ANR Agent, UGA Extension Forsyth County
Dark mornings and evenings and colder temperatures at night let us know that winter is on the way. It may seem paradoxical, but October to December is the time to plant spring-flowering bulbs. That’s because most types of spring-flowering bulbs need 3-4 months of cold to stimulate those cheerful flowers to bloom.
Where to plant spring-flowering bulbs
Bulbs tolerate a range of soil conditions, and spring flowers brighten up the regular full-sun focal spots, like dooryards, flower beds, and that area around the mailbox. But early blooming spring bulbs can add pops of colorful beauty to wooded spaces, as well. Locate these bulbs where they can soak up full sunshine while the surrounding trees are dormant and leafless.
Layering bulbs for waves of blooms
The term “bulb” includes true bulbs as well as perennial producers such as corms, tubers, tuberous roots, and rhizomes. Spring-flowering bulbs bloom in a wide variety of colors, shapes, and heights across the spring season. Bulbs are planted at different depths, depending on size and type. By layering bulbs vertically in the planting, we can get weeks of changing colors and blooms, even small gardens and planters.
To create a layered – or lasagna – garden, select a variety of small and large bulbs; early, mid, and late season bloomers; tall and short growers; and complementary colors. (See the chart below for guidance.) Dig the planting area down to 6-inches, or the planting depth for the deepest bulbs. Place the deepest-planted bulbs in the desired arrangement, keeping root ends pointed down and shorter bloomers forward of taller bloomers. Cover the area with 1-2 inches of soil and arrange the mid-depth bulbs, then cover them with 1-2 inches of soil and place the shallow layer bulbs. Add the final layer of soil and place rhizomes just below the soil surface.
While some bulbs will naturalize or spread over time, others, including tulips and hyacinths (Hyacinthus orientalis) decline and may fail to bloom after a year or two. Fall is the time to dig up crowded bulbs and divide them to share or replant elsewhere.
Forsyth County Extension is hosting an on-line, spring bulb fundraising event, featuring many wonderful flowering and foliage bulbs for fall planting and layered gardens. Order online at https://store.giveandgarden.com/pages/fundraiser/forsyth-county-extension-forsyth-county-extension-fundraiser. Proceeds from purchases will support Forsyth County Extension Master Gardener and Master Naturalist volunteer outreach projects and programs.
Chart 1. Selection Guide for Layering Spring-flowering Bulbs
Common Name | Botanical Name | Type/ Planting Depth | Flowering Height | Flower Color |
Very Early Bloomers | ||||
Crocus | Crocus | Corm/ 2” | 4” | White, Yellow, Purple |
Winter Aconite | Eranthus hyemalis | Tuber/ 2” | 4” | Yellow |
Iris – bulbous | Iris danfordiae, I. reticulata | Bulb/ 2” | 5-6” | Violet to purple with white and yellow markings |
Early Bloomers | ||||
Anemone, Greek Windflower | Anemone blanda | Tuber/ 2” | 6” | Blue, red, white, pink |
Glory of the Snow | Chionodoxa luciliae | Small bulb/ 2” | 5” | Blue, white |
Snowdrops | Galanthus nivalis | Small bulb/ 2” | 6” | White |
Grape Hyacinth | Muscari botryoides | Small bulb/ 3” | 5” | Purple, white |
Siberian Squill | Scilla siberica | Small bulb/ 3” | 4” | Blue, white |
Midseason Bloomers | ||||
Crown Imperial | Fritillaria imperialis | Large bulb/ 6” | 3’ | Yellow, Orange, Red, Burgundy |
Hyacinth | Hyacinthus orientalis | Large bulb/ 4” | 10” | Many |
Spring Starflower | Ipheion uniflorum | Bulb/ 3” | 6” | White, blue, purple, pink |
Narcissus, Daffodil, Jonquil | Narcissus species & hybrids | Small to large bulbs/ 3”-6” Early-mid season | 6-24” | White, Yellow |
Rain Lily | Zephryanthes species & hybrids | Small bulb/ 2” | 6-8” | White, Yellow, Pink |
Late Season Bloomers | ||||
Lily of the Valley | Convallaria majalis | Rhizome/ just below soil surface | 8” | White |
Spanish Bluebell | Endymion hispanicus | Bulb/ 3” | 8” | Blue |
Iris – rhizomatous | Iris siberica, I. kaempferi | Rhizome/ just below soil surface | 3’ | Many |
Tulip | Tulipa species & hybrids | Bulb/ 4”-6” | 3-30” | Many |