In most regions, spring is announced by the blooming of spring bulbs in the landscape. Spring-flowering bulbs offer a colorful display when the rest of the landscape is still waking up from its winter dormancy, and best of all, they require very little effort to grow. The best results are achieved if you follow these 13 simple tips.
Pick the Right Species for Your Region
Many of the classic spring bulbs—such as daffodils, tulips, hyacinths, and crocus—require a cold-chilling period of as much as 16 weeks to "reset" themselves for spring blooming. Gardners in USDA zones 3 to 8 generally are able to successfully grow most spring-flowering bulbs. But if you live in a region where winters do not provide that kind of extended cold period below 40 degrees Fahrenheit, you will have trouble growing these bulbs—unless you artificially chill the bulbs in the refrigerator or buy the bulbs prechilled.
If you are a warm-weather gardener and don't want to go through the trouble of artificially chilling the bulbs, then stay with later bloomers, such as amaryllis, paperwhites, ranunculus, and anemones.
Choose Healthy Bulbs
Avoid bulbs that appear withered, spongy, or moldy. In general, the larger the bulb is for its type, the more flowers it will produce. Small bulbs are typically less expensive but will have smaller or fewer flowers. However, when you are dividing an established group of bulbs, it's fine to save the small bulbs—just be aware that it may take a couple of years until they are vigorous enough to produce flowers.
Select a Good Location
Most flowering bulbs prefer full sun. But don't overlook a spot in your garden just because it's shady in the summer and fall. Spring bulbs flower early, before most trees have their leaves, so you can plant beneath the canopy of shade trees with impunity. But don't plant spring bulbs in a place where there is permanent shade, such as in the north-side shadow of a house, garage, or fence.
However, note that woodland bulbs—such as Anemone nemorosa (woodland anemone), Arisaema (Jack-in-the-pulpit), Erythronium (dog's tooth violet), Galanthus (snowdrop), and trillium—prefer a bit of shade in their planting location. Always check the cultural needs of bulbs before you plant them.
Consider Design Principles
Bulbs tend to look best in clumps or drifts, which gives them a natural appearance. To achieve this, either dig a large area and plant several bulbs at once, or simply toss the bulbs in the air and dig holes and plant wherever they fall. Some gardeners insist that planting groups of bulbs in small groups of odd numbers—three, five, or seven—gives a more natural look in the landscape. But you should generally avoid planting in geometric rows unless you are deliberately aiming for an artificial effect.
Plant at the Right Time
It's a standard rule of thumb that spring-flowering bulbs are planted in the fall, but the fall season stretches over 12 weeks, after all, and there's a notable difference between temperatures and soil conditions at the start of fall in late September and in late November.
The best time to plant will vary depending on the type of bulb and your region. Check with your local University Extension Service or a good local nursery for recommendations on when to plant a particular species. For example, in Minnesota, it's recommended that daffodils should be planted in September, while the recommendation in Tennessee is to wait until late November.
A good strategy that works for most spring bulbs is to wait until air temperatures are reliably below 50 degrees and soil temperatures are at, or below, 55 degrees Fahrenheit. Most spring-flowering bulbs can be planted all the way up to the point where the soil is frozen solid.
Evaluate and Prepare the Soil
Bulbs don't like to sit in wet soil, as constant moisture is likely to cause rot. This is especially true when they are dormant in the summer. So choose a planting site that has good soil drainage year-round, but especially through the summer. Many spring bulbs originate with species that are native to arid regions such as the Mediterranean, and they will grow best in soil conditions that mimic those areas.
It's often a good idea to blend some bone meal or superphosphate into the soil at planting time to encourage strong root growth. Or, you can sprinkle a handful of bulb fertilizer into the bottom of each hole.
In subsequent years, additional bone meal or fertilizer can be scratched into the soil above the bulbs each spring, or you can apply a general-purpose water-soluble fertilizer during the active growing period, which will help boost the vigor of the bulbs for the following season.
Plant at the Right Depth
In general, bulbs should be planted to a depth of about three times their diameter. For daffodils, that’s about 6 to 8 inches deep. Interestingly, bulbs planted at less than ideal depths will often self-adjust within a year or two, shifting their depth in the soil.
Place Bulbs Right-Side Up
Many bulbs have an obvious up and down orientation. The pointed end of a bulb is generally the stem and should face up when you place the bulb in the planting hole. You might even be able to see some shriveled, hair-like roots on the flatter, downward end of the bulb.
Sometimes, though, it's difficult to tell which end is up. If so, simply plant the bulb on its side; the stems will generally find their way to the surface. In fact, even bulbs planted upside down will generally sprout and flower, though it may take them a few extra days.
Protect the Bulbs
Squirrels and other rodents are notorious thieves of many spring-flowering bulbs. If you find this to be a problem, you can ensconce your bulbs in hardware cloth—a metal fabric that allows the roots and stems to easily grow but prevents rodents from getting to the bulbs.
Another method is to sprinkle red pepper into the planting hole, which will deter rodents from digging up the bulbs. Or, you can limit your bulb selection to species that rodents and other animals tend to avoid, such as daffodils.
Remember the Planting Site
To make sure you don't disturb your bulbs by trying to plant something else in the same spot after the foliage has dried up, make sure to mark where and what you have planted. The marker can be as simple as a small wooden craft stick with the plant name written on it. Or you can keep an annual garden map that carefully shows where each bulb group is growing.
Watering the bulbs immediately after planting will help them settle and close any air pockets in the soil. During the growing season, water sparingly—no more than once a week. Many spring bulbs originate in relatively dry regions, so excess water is generally not a good idea. Then, through the fall and winter, you only need to worry about watering your bulbs if you’re having a particularly dry season. Come spring, you should be well rewarded for your effort.
Follow Proper Aftercare
When your bulbs have finished flowering and the foliage has died, cut back the flower stalks to ground level. Resist the temptation to cut back the stalks when they're still green but floppy. The bulbs need this time to photosynthesize and make food reserves to produce next year’s flowers.
Divide Bulbs When Needed
Many bulbs spread and produce more plants, which can make the planting site overcrowded after a few years. If your bulbs aren't flowering as well as they used to, overcrowding might be the culprit. You can divide your bulbs when they begin entering their dormant period, usually just after the foliage completely dies back. Note that dormancy is brief, so don’t put off this task.