Prep Now for Spring
Even as summer turns to fall, it's time to think spring. Now into early autumn is the ideal time to plan, plot out, and prep beds and borders for swaths of colorful flowering bulbs.
Depending on your climate and growing zone, store shelves will soon be stocked with crocus, tulip, daffodil, allium, hyacinth, and other bulbs. Catalog companies are already taking orders. Planting bulbs is certainly easy enough: Dig a hole three times as deep as the bulb is high, toss in some bone meal, drop in a bulb with the pointed tip up, cover with soil, lightly tamp down; repeat.
But a few simple and sensible ideas can help you get a bigger, better display without having to guesstimate quantities, Google optimal planting times, or figure out how to camouflage dying foliage come May. So whether you're a "tulipomaniac" looking for a few fresh ideas or a novice who just picked up a bag of bulbs at the home store on a whim and are wondering where to begin, we've got advice in spades on the pages that follow.
Shown: A hand bulb planter speeds the job of making dozens and dozens of holes to drop bulbs into.
Do the Math for Fuller Beds
Don't estimate, calculate! The key to a beautiful show of bulbs is planting enough—and most of us simply don't.
TOH Tip: Look for bulbs that are big, fat, and firm with no visible signs of mold or damage.
A (area) × B (bulbs) = C (color)
Change this by following guidelines from bulb growers for recommended quantities, at left. The math is simple: Figure the square footage of the space you wish to plant, then use our chart to determine the quantity of a specific bulb you'll need per square foot. Adjust quantities based on the size of your bulbs. Generally, top-size tulip bulbs are 12cm or larger in circumference; daffodils at least 16cm. So, for example, to plant a 10-square-foot bed with large tulip bulbs, multiply 10 × 6 for a total of 60 bulbs. Think of it as A (area) × B (bulbs) = C (color).
Shop Early, Plant on Time
Put off buying bulbs and you risk missing out on the best colors or unique varieties—you might also be left with bulbs that are not in peak condition. Once they are removed from the ideal environment of a growing facility, the race is on to get bulbs in the ground before they go mushy or dry out and split. Most vendors ship bulb orders based on your growing zone, but it's good to know the optimal window for planting. Ideally, bulbs should be in the ground six weeks prior to the first ground-freezing hard frost. The chart above is synced to the USDA Climate Hardiness Zone Map. Follow the color key to know when to plant spring-flowering bulbs in your area. In the warmest-winter regions (Zones 7 through 11), most bulbs that produce large flowers—including tulips, hyacinths, and alliums—require supplemental chilling. Store them in an empty crisper drawer in a refrigerator for at least eight to 10 weeks prior to planting.
Layer Bulbs for Successive Blooms
By planting different varieties of bulbs with staggered bloom times at different depths in the same hole, you can have flowers from early through late spring, even in a tight space. A 1-foot-diameter planting area dug 1 foot deep can accommodate seven large bulbs, such as daffodils, six medium-size bulbs, such as tulips, and eight small bulbs, such as crocus.
Once you've dug the hole, enrich the removed soil with a shovelful of compost and set aside. Mix a balanced (10-10-10) fertilizer with the loosened soil at the bottom of the hole; in clay soils, add a 1-inch layer of sand or pea-size gravel for drainage. Place the largest bulbs in the hole, roots down and pointed tip up, close but not touching (overcrowding can deter blooming). Press bulbs firmly to ensure good contact with soil, then cover with 2 inches of your reserved soil mix. Repeat with the medium-size and then smallest bulbs, covering with the last of the reserved soil. Water well and keep moist throughout the fall, then cease watering until spring. Watch waves of colorful blooms for four to six weeks come spring.
Interplant Bulbs with Perennials
Spring-flowering bulbs and early-to-midsummer-blooming perennials go hand in hand. In a mixed border, bulbs launch the first round of color before perennials emerge to hide fading—but critical to keep—bulb foliage. The trick is to match bulbs and perennials that bloom in sequence and whose foliage height and scale are complementary. Cornell University's Flower Bulb Research Program tested dozens of combinations to get the best pairings. (Find the full list at thisoldhouse.com/sep2014).
Shown: Late spring's 'Purple Sensation' allium wraps up its bloom just as sea holly (Eryngium planum) and purple Salvia nemorosa 'Caradonna' (foreground) come on for summer.
Interplant Bulbs with Perennials: Tulip
Works well with:
Crocosmia 'Lucifer' (Crocosmia 'Lucifer')
Meadow cranesbill (Geranium pratense 'Splish Splash')
Oriental lily 'Stargazer' (Lilium 'Stargazer')
Interplant Bulbs with Perennials: Allium
Works well with:
Bigleaf aster (Aster macrophyllus)
Star gentian (Gentiana cruciata)
Sage (Salvia nemorosa 'Caradonna')
Interplant Bulbs with Perennials: Hyacinth
Works well with:
Maltese cross (Lychnis chalcadonica 'Carnea')
Chinese rhubarb (Rheum palmatum 'Atrosanguineum')
Sedge (Carex morrow 'Ice Dance')
Interplant Bulbs with Perennials: Crocus
Works well with:
Chinese ground orchid (Bletilla striata)
Hosta 'Patriot' (Hosta 'Patriot')
Geranium 'Biokovo' (Geranium cantabrigiense 'Biokovo')
Interplant Bulbs with Perennials: Daffodil
Works well with:
Catmint 'Six Hills Giant' (Nepeta 'Six Hills Giant')
Phlox 'Bill Baker' (Phlox paniculata 'Bill Baker')
Fern-leaf yarrow 'Gold Plate' (Achillea filipendulina 'Gold Plate')
Make Up for Lost Time
Say you missed your chance, the ground is now hard, and you've ended up with bags of unplanted bulbs sitting in the garage. If left out of soil for too long, bulbs will dehydrate and die. But all may not be lost. If garden soil is frozen or very wet from winter rains, wait for a thaw or a break in the weather and plant bulbs a little deeper than normal to protect emerging roots from the cold. Or plant the bulbs in pots and place them in a cool (not freezing), dark spot, watering sparingly throughout the winter, then bring the planted pots outside in the spring. As a last resort, leave the bagged bulbs where they are, and in early spring, plant them when the ground starts to thaw. You might still get a few blooms this season.