Bulbs 101 – The Short Course

At Colorblends, we want you to have a great spring display. But let’s face it – planting is hard work. We suggest you order in small bites to learn what it takes to get bulbs planted in the fall. If you like the result in the spring and you feel you can do more, order more the following fall. This gradual approach will be good for your back, your budget, and your learning curve.

Here is a quick overview of bulbs that is intended to help you make an initial order, get your bulbs into the ground, and care for your bulbs after you plant them. Please note that the following information applies specifically to the Colorblends product line: bulbs that are planted in the fall and bloom in the spring.

“Bulb” Defined

The word “bulb” in botany has a very precise meaning. In gardening and horticulture, the definition is quite loose: a plant that makes a dense, usually hard, underground storage organ. What is the bulb storing? Energy. More on that under the Bulb Growth Cycle below.

Bulbs can take a variety of forms and sizes. Some are smooth, some are shaggy, some are lumpy and bumpy. Some have pointed tops, indicating “this end up.” Others defy attempts to tell top from bottom. Some can grow to the size of a baseball. Others are very small, just half an inch in diameter, or even less. When you receive them in the fall, bulbs appear to be lifeless. Many look like stones (and can be nearly as heavy). They are, in fact, alive.

All bulbs are perennials. There is no need for a plant to make a storage organ if it is only going to live for one growing season. Does that mean that all bulbs bloom every spring for years on end? No. Tulips in particular are at their best the first spring after planting. After that, all bets are off (for more information on the longevity of tulips, see our Perennial Tulips article). Daffodils and many specialty bulbs have the ability to settle in and give many spring performances.

The Bulb Growth Cycle

Spring-flowering bulbs have a growth cycle that is different from that of most other plants. They make roots in the fall in preparation for winter. In spring, they push leaves and flowers up above ground. The leaves persist until early summer, and then they turn yellow and dry up. The plants appear to be dying. In fact, they are entering dormancy. The bulbs sit in the ground through summer doing little or nothing, until the soil cools in fall. The bulbs then make new roots, and the cycle begins anew.

During the few months that bulbs have leaves, they store up the energy they will need to grow and flower the following spring. The energy comes from the sun, the primary source of all energy on Earth.

Flowering is a luxury; the priority is survival. If the leaves are cut prematurely or the bulbs are planted in a location where they don’t receive sufficient sunlight, the bulbs will forego making flowers, using what energy they are able to store to make leaves the following spring. Bulbs can persist this way (making leaves but not flowers) for many years, while they wait for an opportunity to store up enough energy to bloom.

People long ago discovered that bulbs can be dug, shipped, and stored for long periods during their summer dormancy. The bulbs you receive in the fall were dug from fields in the Netherlands between late spring and midsummer, soon after the leaves died back. They were then cleaned, graded by size, cured and dried, packed, and shipped across the Atlantic in ocean containers. They will tolerate being out of the ground right through fall and even into early winter, but they must be replanted before serious winter cold descends. If they are not replanted, they dry out and die. Few unplanted bulbs will make it to spring.

Bulb Requirements

You now know that bulbs are plants that need a lot of light to grow and flower well. Some bulbs can get by with less light than others. They can be planted in the shade of trees that lose their leaves in fall because they pop out of the ground early in the spring and are able to get most of the light they need before the trees leaf out. You can find these bulbs on our Shade Tolerant Bulbs page.

In addition to sunshine, most bulbs need good drainage. What does “good drainage” mean? Soil that does not retain excessive amounts of water. Most bulbs come from dry places. They need access to moisture from fall through spring, but they can’t tolerate soggy soil. This is especially true in the summer. If you have wet spots in your yard or landscape, you probably know where they are. When it rains hard and you see areas where the water takes a day or three to soak into the ground, those are the places where you should not plant bulbs.

Figuring Out How Many Bulbs to Order

Determining how many bulbs to buy can be challenging. If you’re going to fill a bed with one kind of bulb, all you need is the square footage of the bed and the recommended number of bulbs to plant per square foot. We provide square footage calculation formulas on our How Many Bulbs Do I Need? page. The recommended number of bulbs per square foot is provided on the Planting Guide tab for every item on this website.

But what if you want to combine two different kinds of bulbs in the same bed? Or you want to try a different planting style, a bouquet planting, perhaps, or you want to sprinkle bulbs through a perennial garden? There are no rules of thumb for such plantings. Bulbs can be used in many ways, but the creativity they allow requires guesswork when it comes to figuring out how many bulbs to order. If you are struggling with a particular problem, give a call. We will do our best to help.

Planting Bulbs

Planting bulbs is hard work. There is no way to sugarcoat that fact. Bulbs need to be planted somewhere between 2 and 7 inches below ground, measuring from the surface of the soil to the bottom of the hole. Planting depth depends on bulb size: The larger the bulb the deeper the hole needs to be. (Planting depths are provided for every item on this website. Click on the Planting Guide tab below the item photo to find the recommended depth.)

There are two basic planting techniques. One is to dig a hole for each bulb, put the bulb in the hole, and then push the soil back into the hole. The second is to excavate the entire area to be planted, set the bulbs in place, and then push the soil back over the bulbs. The second technique is illustrated in our video How to Plant 100 Tulips in 30 Minutes. If you are planting small bulbs like winter wolf’s bane or glory of the snow, you can throw several bulbs in each hole you dig. They will come up in the spring as tight clusters. (Don’t worry which end is up: Bulbs know to send shoots up and roots down.)

To repeat: This is work. People who are new to bulbs sometimes order like kids at the candy shop who have just received their allowance. Enthusiasm is good, but we suggest you go slow to start with. As you learn how much you can handle and begin to understand what your labor will yield in the spring, you can always come back next year and order more.

Caring for Bulbs

Bulbs don’t require a lot of care. When you receive them in the fall, next spring’s flowers are already set inside them. They are programmed to bloom, and they will bloom, unless something prevents them from doing so.

Still, like all plants, bulbs have basic needs. As noted above, they need plenty of sunshine and soil that drains well. They also need water. Bulbs need access to moisture from planting time through bloom. In many parts of the U.S., this moisture is supplied naturally by rain and snow. Get the bulbs into the ground, and you are done. In dry parts of the country, the bulbs will need to be watered after planting, and watering will be required if rainfall is scarce in fall, winter, or spring.

Bulbs also need nutrients. Flowering the first spring after planting is guaranteed, but to grow and flower well in future springs, bulbs need access to nutrients in the soil. Most soils contain these nutrients in sufficient abundance. That’s why Colorblends does not sell fertilizer, which is basically nutrients in a bag. People tend to think that plants need fertilizer to grow and flower properly. Plants may need fertilizer, but the only way to know that plants need fertilizer is to have the soil tested by a soil testing laboratory. If the plants in your garden or landscape are growing reasonably well, skip the fertilizer. If you think there might be something wrong with your soil, have it tested. When in doubt, don’t fertilize.

After your bulbs have flowered in the spring, you might want to remove the spent blooms (a practice known in gardening as deadheading). In the case of daffodils, this is done for cosmetic reasons. For tulips, snapping off the top few inches of the flower stem helps divert energy that might go to seed production back into the bulb. Many people leave the flower heads of the tall alliums in place after bloom as an architectural element in the garden. They can persist well into summer before being knocked down by rain or wind.

Beyond deadheading, you need to do something that some people find difficult: nothing. How could that be hard? Remember: Spring-flowering bulbs go dormant in summer; their leaves and flower stems will turn yellow and dry up after they flower. You must wait until the foliage has yellowed before you remove it. The leaves are the food factories of bulbs (of all plants). If you cut the foliage while it is still green, you are preventing the bulb from capturing and storing the energy it will need to grow and bloom the following spring. Many bulbs close up shop within a few weeks after flowering. Daffodils in particular take a long time to say “good night.” They can drive people who prefer a tidy garden crazy. But you cannot and must not interrupt the daffodil’s swan song by cutting or folding the leaves. As we like to say: This year’s leaves = next year’s flowers.

One last thing: Bulbs can be moved and divided. You may decide that a group of bulbs planted in one location should be moved for aesthetic or horticultural reasons (e.g., excessive shade). Or you may find that a cluster is so happy that the foliage has become crowded and flowering has declined. The thing to do in both cases is to dig the bulbs and replant them. Timing and techniques are provided in our short article Moving and Dividing Daffodils. The article is specific to daffodils, but much of the information also applies to other spring-flowering bulbs.

Class Dismissed

Thank you for reading this far. The reward for your patience is a solid understanding of bulb basics. You will find more information on this website. If you have a question that is not answered here, please drop us a line or give a call. We are fall bulb specialists. We will do everything we can to help you succeed.