Making a successful, beautiful bulb landscape doesn’t begin at planting time. It begins when you go buying or swapping bulbs. Neighbors can be a great resource for extra bulbs when they are dividing their bulbs. But do be picky: Free bulbs aren’t a bargain if they aren’t strong and healthy.
How to choose bulbs to plant
Bulb quality can vary, so starting with good ones is important. Here’s what to look for:
A fresh, good-quality bulb is plump and clean, without obvious damage to its outer layers. Avoid bulbs with disfiguring dents or blemishes, which can let in rot-inducing bacteria. Bulbs may contain a small amount of green penicillin mold, which is rarely harmful. Some bulbs, like anemone and ranunculus, always look dried up.
Pick up a bulb and handle it for a moment. Then pick up a few others from the same basket or bin (of the same variety) and compare their weights. Bulbs that feel lightweight relative to their peers are likely to be dried out and not viable (they may even be last season’s leftovers). While you’re at it, gently squeeze the bulb. A squishy texture indicates rot, but a good, firm feel means the bulb has sufficient moisture content.
With bulbs, bigger is better. A larger bulb has more stored reserves and therefore can produce larger and more flowers on more substantial stems. You get what you pay for; you can get incredible deals on bulbs, but they may be too young and small to bloom.
PS: When selecting your bulbs, read bin or packaging labels with care so you know the names of what you’re buying as well as something about the plants, like how tall they get, when they bloom, whether they grow in sun or shade, and how far apart and deep to plant them.
When to plant bulbs
Bulbs aren’t instant-gratification plants. They need some time in the ground before they send forth stem, foliage, and flowers. But they are not inert when they are in the ground, of course. They are generating root growth, which will help nourish the show as well as anchor the plants in place.
Planting spring-blooming bulbs
Spring-blooming bulbs require a chilling period. They are dormant when you get them and break dormancy only after the chilling. Winter conveniently supplies this necessary cold period. That’s why you put the bulbs in the ground the fall before you want them to bloom.
Planting summer-blooming bulbs
Most summer-bloomer bulbs, such as Gladioli, Calla lilies, Dahlias, Tuberous Begonias, and Crocosmias, love warm soil and toasty summer sun. If you garden in a mild climate, you can plant these bulbs in the early spring and expect flowers by summer. If you garden in a colder area, early spring planting isn’t feasible. Instead, wait until late spring or early summer, or start bulbs early indoors in a warm spot and care for them until the danger of frost has passed; then you can move the plants outdoors.
In either case, regular doses of all-purpose fertilizer (applied according to label directions) can nudge your plants into faster, more robust growth and more and better flowers.
To get bulb flowers earlier and longer from these summer bloomers, visit a nursery in late spring or early summer and buy a larger, pre-started plant.
Planting fall-blooming bulbs
Spring gets all the attention, to be sure, but some bulbs bloom in fall, and they are gorgeous, easy to grow and they are a wonderful sight to behold when the gardening year is winding down. Among this group are the Autumn Crocus (Colchicum autumnale, no relation to true crocuses or Crocus speciosus), winter daffodil (Sternbergia), Guernsey lily (Nerine bowdenii), saffron crocus (Crocus sativus), and even a species of snowdrops (Galanthus reginae-olgae). If your local garden center doesn’t have these, look for them in specialty bulb catalogs or on gardening Web sites.
Fall-blooming bulbs have a dormant period too: summer. Thus, you ought to plant them in late summer – as soon as they’re available – because the plants are ready to wake up. Some bulbs, like the Autumn Crocus, send up their leaves in spring and flower leafless in fall. Usually, these bulbs spring to life soon after planting – within a few weeks – though you’d best mark the spot so you don’t forget them and plant something over them. In any event, the flowers will arrive on schedule.
Where to plant bulbs
Bulbs are some of the least demanding of all plants, but they appreciate your efforts to give them as good of a growing area as possible (with well-drained soil); they may reward your efforts with years of bountiful flowers.
Planting bulbs in flower beds
Flowering bulbs are very happy in prepared flowerbeds. They receive the good, loose soil they relish and the elbow room they need. Here are two good approaches:
Planting bulbs in bedding schemes:
Perhaps you’ve seen these beds in public display gardens: broad areas devoted to nothing but, say, tulips. The mass of color can be very impressive. You can prepare these flowerbeds at home. Pick a nice, open spot, choose a large amount of the same or very similar bulbs (in terms of color, height, and/or bloom time), and plant them fairly close together.
Planting bulbs in mixed beds:
Bulbs are only part of the show in a mixed bed; they can share the stage with early-blooming perennials, some colorful annuals, and perhaps a few sheltering shrubs. The overall show never declines: Whether you’re waiting for the bulbs to burst into bloom or waiting for their fading foliage to die down, you always have something to look at and enjoy.
Planting bulbs in containers
Growing bulbs in containers handily solves every display problem. Individual plants can get exactly the sort of soil and planting depth they prefer. When the bulbs come into bloom, you can place them front and center on your porch or patio or even tuck them into a flowerbed and enjoy them at their peak. You can turn or elevate the container to show off the flowers to the best advantage. And when the blooms and foliage begin to fade away, you can move the plants out of sight and replace them with pots of fresh reinforcements.
Something about a potful of blooming bulbs is so immediate and perky. They’re right before your very eyes, cheerily delivering their jolt of color. You can line your front steps with them or place a pot in the middle of the patio table, like a living bouquet.
Pots dry out faster than garden-bed soil. Keep your potted bulbs watered. Consistent water (that is, every day or two instead only when the plants are gasping) leads to a healthier, longer-lasting show. Also, if you’re in a cold climate, be sure to pot your bulbs in containers that can freeze without breaking, like plastic.
One drawback: In most climates, bulbs grown in containers are spent after one blooming cycle. If you enjoyed them, you have to start over next year with fresh new bulbs, unless the pot is large enough for the bulbs to go through their dormancy and remain in good health.
How to plant bulbs
Planting bulbs is simple. But before you start, be sure the chosen spot has good and well-draining soil. Bulbs rot in soggy ground and struggle in sandy soil; the addition of some organic matter eases these problems considerably.
Follow these planting steps for the best results:
1. Dig the hole
If you are planting only a few bulbs or you are spot-planting (tucking bulbs in among other plants in a mixed bed), use a trowel. Various bulb planters are on the market, but frankly, I don’t find them very useful unless the soil is loose. If you’re planting lots of bulbs, break out the shovel and make a trench.
Not all bulbs are the same size, so not all bulbs should be planted the same depth. The general rule is three times as deep as the bulb’s height. This guideline varies a bit based on your soil type. In sandier soils, you can plant a little deeper; in heavy clay soils, a little shallower. If you forget how deep to plant your bulbs, consult the supplier’s label or catalog. Too shallow, and your bulbs may poke their heads above the soil surface too early and get damaged by wintry weather; too deep, and they’ll take longer to emerge.
Roots grow out of the bottom of the bulb, so the quality of the soil underneath it is more important than what you pack the hole with. If you’re amending the soil with organic material like compost or sphagnum moss, dig somewhat deeper-than-recommended holes so you can accommodate this addition.
Distance apart varies with the type of bulb and the sort of display you have in mind. If you crowd the bulbs underground, the eventual show may suffer. Certainly, don’t let the bulbs touch one another. The general rule is at least three bulb-widths apart “on center” (from the center of one bulb to the center of the next). But experience can tell you what the bulbs you’ve chosen tolerate and how dense you like your displays.
2. Add a fertilizer
Use a fertilizer that has a higher phosphorus number, such as a 5-10-5 fertilizer. Phosphorus (the P in the N-P-K on fertilizer labels) is important for the root growth as well as flower production. Just sprinkle the fertilizer in the bottom of the hole and scratch it in so it mixes with the soil a bit.
If the ground is bone dry, water a day or so before planting so the ground is damp but not muddy when you’re planting the bulbs. If you want to wait to fertilize, you can scratch the fertilizer into the surface of the soil in the spring as the bulbs are growing.
3. Put the bulb in the planting hole
You want the nose, or growing point, to point up and the roots, or basal plate from which they’ll grow, to point down. Make sure the bottom of the bulb is in contact with soil; if you leave an air pocket, the roots can dry out and the bulb won’t grow or won’t grow very well.
4. Backfill and water
As you scoop soil back into the hole, firmly press it in place to prevent air pockets. Water well (some settling will occur) and then add a bit more soil as needed.
Indicate where you’ve planted your bulbs so you don’t plant other flowers in the same place. Mark the locations with permanent nonrusting, nonrotting labels like those made of zinc or copper.
Caring for bulbs
Because bulbs come as a package of life – that is, with the embryonic plant and flower within, plus stored food to fuel the growth – they demand little from you, the gardener. With a little tender and loving care, they can do their thing and be wonderfully reliable.
Just like grocery-store onions, bulbs rot with too much moisture. And yet, they need water to generate roots and get growing. But don’t fret, there’s no mystery or careful balancing act. Just grow bulbs in well-drained soil; they can use the water they need, and any excess moisture should drain away.
Fall-planted, spring-flowering bulbs have it easy if you live where fall rains water them in and spring rains wake them up. Summer and fall bloomers appreciate water most when they’re beginning to emerge and again when they open their flower buds. Water at these times only if the soil is dry.
Although newly planted bulbs have all the stored foods they need to perform the following spring, annual fertilizing can help keep this show going year after year.
A general-purpose fertilizer works fine for bulbs. Higher phosphorus content is often recommended simply because it inspires root growth as well as flower production. So go ahead and use the 5-10-5 or something close to this ratio.
People often recommend bone meal for bulbs, with its approximate formulation of 2.5-24-0. Alas, modern-day, store-bought bone meal is highly sanitized, and its benefits are questionable. Nonetheless, some bulb enthusiasts swear by it. This natural material tends to be very slow to release its nutrients, so some gardeners prefer using superphosphate instead; this material is rock phosphate that has been treated with sulfuric acid to make it more soluble. It’s 20 percent phosphorous (0-20-0).
Some people debate over where to place the fertilizer. In the hole? On the soil surface (top-dressing)? The case for adding plant food to the planting hole is that it’s right at the roots, where plants need it (some people are concerned that direct contact with fertilizer will burn a bulb or its roots, but not all bulbs are so fragile). The case for soil-surface feeding is that nutrition can filter into the growing area more gradually.
What to do? Try whichever way is more convenient for you, and judge the results. You can always switch methods.
You need to fertilize only once, and you have three opportunities to do so:
At planting time (usually in the fall): I describe this option in the previous “How to plant bulbs” section. Fertilizing at planting time gets the bulbs off to a good start.
As growth starts, usually in early spring: This fertilizing improves the current season’s display. Individual plants will be more robust, with brighter, longer-lasting blooms.
Post-bloom: While the foliage dies down naturally, this little boost sends food down to the bulb to fuel next year’s show.
The standard application rate for fertilizer is a tablespoon or small handful per square foot, but read the label on the fertilizer package for exact directions. Always apply fertilizer to damp ground, and water it in afterwards if there’s no rain so it penetrates the soil and gets to the root zone.
Mulch helps keep down weeds, can add organic matter to the soil, retains moisture, and stabilizes the soil temperatures. Stable soil temperatures are important so the bulbs don’t sprout too soon and risk freezing damage from a late spring cold snap.
Shredded leaves, compost, or bark chips are all fine choices for mulch. Sprinkle it lightly around your bulbs just after planting them or when they’re up and growing. And add some more mulch after the show is completely over.
Fighting bulb pests
If you were a rodent tunneling around underground and you came across a nice, plump bulb, how could you resist? The main predators of bulbs are mice and voles.
Squirrels and chipmunks are more likely to sniff out the tasty treats above ground and dig up your bulbs, sometimes strewing remnants about your yard. These rascally rodents are enough to make even the most mild-mannered gardener homicidal.
Rodents love Tulips and Crocuses, but they avoid Daffodils, Fritillaries, and Amaryllis and its relatives (these bulbs are poisonous, and the critters seem to know it). Here are some strategies for keeping your bed of bulbs rodent-free:
- Fill each planting hole with small, sharp gravel.
- Make a “cage” of screen or hardware cloth, fill it with soil, plant your bulbs inside it, and then bury it at the correct depth.
- Make a raised bed especially for bulbs. This bed should be about a foot deep. The bottom layer, at least 2 inches thick, should be small, sharp gravel. To accommodate the bulb’s roots, at least 6 inches of good soil can go over the gravel. Plant the bulbs and cover with 2 inches of gravel or even sand. Last, lay a thick layer of mulch (up to 6 inches) of hay, pine needles, or shredded leaves over everything. Remember to rake off the mulch when spring comes.
- Prior to planting, spray your bulbs with a foul-tasting repellent marketed for this purpose. Two common brands are Mole-Med and Ropel. Let the bulbs dry before planting. Castor oil is also a common, safe, and reasonably effect repellent that you can apply to the bulbs and/or the ground they grow in.