Frost-Tender Bulbs for Cool-Climate Spring Containers
Imagine this scenario: You’re a passionate gardener living in USDA hardiness zones 4–7 and you simply love those frost-tender bulbs. You think you’re doomed. After all, those bulbs won’t survive in your garden, right? Hold on! You can add these bulbs to your garden, and we’re going to show you how—with container gardening.
What bulbs are we talking about here?
Oh, you know, nothing special—just dramatic calla lilies, sumptuous ranunculus, vibrant anemones, lush tropicals, and the like. There are loads of tender bulbs that are ideal for container planting, and these are seven of our favorites:
Freesia: This South African native makes excellent cut flowers, have strongly colored blooms, and an intoxicating fragrance. Plant them in a sunny location in the spring for late summer bloom.
Ranunculus: These ruffly beauties have strong stems, making them perfect for flower arranging. The Italian ranunculus offer a few more bloom colors, but really? All the ranunculus are divine. Plant these in the spring for late summer bloom!
Calla Lily: Elegant calla lilies are another option for bouquets and flower arrangement because of their long, strong, and straight stems. Typically summer bloomers, they might appreciate a bit of filtered light or moderate shade to bloom their best.
Anemone: Vibrant anemones come in single or double varieties, with striking colors and strong stems—another flowering bulb for your flower arrangements! In cooler climates, this one will bloom in late summer or early fall after planting in the spring.
Dahlia: Enormous blooms and delicious hues make dahlias a sought-after cut flower for late summer bloom. Be sure to plant them as early as possible in the growing season since their bloom time is later—you don’t want an early frost killing these lovelies off.
Elephant Ears: If you long for dramatic, tropical-inspired containers, go with elephant ears! These large-leaved plants command attention in part sun to part shade gardens, and keep their leafy goodness going all season long until frost.
- Canna: Dramatic foliage and bright blooms — that’s what tropical cannas are all about! The flowers are typically orange, yellow or red, with foliage that is bright green, dark maroon, or variegated—all gracing your summer garden.
How do I add them to containers?
If you’re familiar with planting bulbs in the ground, the same “how-to” tips apply in terms of planting technique, but there are a few important distinctions when it comes to planting bulbs in containers, especially for cooler climates:
Choose your bulbs. Choose from our list of favorites above, or go shopping over at Easy to Grow Bulbs for more options.
Decide if you want a mixed or single planting. A single elephant ear in a large container or a collection of different bulb varieties? Or both? Just remember the rule of thumb to plant only those plants with the same growing requirements together in one container. No Sun Worshipper with a Cover-Up Queen, please!
Know when to plant. When these tender bulbs are planted in their preferred growing climate (generally, zones 8–11), they are usually planted in the fall for spring or summer bloom. But in your cooler climate, you’ll most likely be planting these bulbs in the early spring for bloom/foliage in late spring/summer/late summer. This is arguably the most important difference—but one that will make or break your tender bulb container garden!
Plant at the correct depth. Container planting with bulbs really is similar to in-ground planting. Follow the planting depth recommendations for each bulb you want to add to a container—the general rule is 2–3x deep as the bulb is tall. So, for example, a bulb 2” high should be planted 4”–6” deep. And if you’re layering those bulbs, start with a layer of soil, then plant your larger bulbs first, adding layers of soil and increasingly smaller bulbs as you go. Click here for more info about how to do that.
- Get inspired! Read our blog post “Lush Foliage & Bright Color!—Tropical Container Gardening” for more container gardening inspiration if you’re into those big tropical drama queens.
What do I do at the end of the season?
When the heat is waning and you’re beginning to notice a chill in the air, you’ve got a couple options with these warmer-climate bulbs.
Treat them as annuals. “What??” You’re thinking. “Put them in the compost pile?” Yes, exactly! We’re not talking about digging up an entire perennial garden of bulbs and tossing them out—we’re talking about more limited numbers in container plantings. View these bulbs just as you do annuals like impatiens and petunias. Give thanks for the season of exquisite color and beauty they brought to your spring/summer garden, then let them be food for next year’s garden.
- Overwinter them indoors. With many of these bulbs, this is as simple as digging up the bulbs or tubers after the foliage has turned yellow or has been killed by a frost. Loosen up the soil around the entire clump, then lift the entire clump and carefully remove any excess soil. Discard any damaged bulbs, let them cure for a couple of days (but maybe longer—do a quick Internet search for the specific bulb you are overwintering), then store in 2–3” of peat moss, sand, or sawdust within a cardboard box or crate. Place the container in a cool, dry area (40–50 degrees is ideal in a basement or root cellar), bringing them out when it’s time to plant in your area again!
- Katie Elzer-Peters