The Best of Bulbs

Creative combinations and innovative planting techniques make the most of your customers' and clients' spring flower displays.
By Jennifer Brennan

Layering several varieties of bulbs can create a long-lasting display of gorgeous spring color.
After a winter of snow, cold temperatures and long nights, we're all eager for a little sunshine - and a little color. And nothing encourages us to get out and enjoy the advent of spring like brilliant displays of blooming bulbs.

Chances are your clients have asked for recommendations, and customers who look beyond the holidays and into the new year will appreciate a good selection of bulbs they can plant now for spring color. But you can help them even further by teaching them to extend the often-brief flowering season with a few easy tricks. Whether they desire basic bulbs or a mix of lesser-known varieties, they'll appreciate the benefit of a longer season of gorgeous spring color.

Extending the season

As glorious as a spring bulb garden may be, the color and fragrance are often fleeting. There are several tricks, however, to extending the bloom season, beginning with planting by species. Even if varieties with similar bloom times are used, the planting depth and the varying heights of the plants dictate that the flowers bloom at different times.

Seven steps for planting bulbs

Ensuring success with a bulb planting is relatively easy if several easy-to-follow steps are taken.

  1. Prepare a well-drained site
  2. Use an amendment if the site has heavy clay soil
  3. Fertilize at planting time; remember to fertilize the soil that covers the bulbs rather than the bottom of the planting hole
  4. Water upon planting, and follow with regular waterings if the site doesn't receive at least 1 inch of rain per week
  5. Select the best cultivars for the site
  6. Plant in time, before the ground freezes solid. The ideal planting time in the Chicago area, for example, is October 1 to October 15, when soil temps are about 50 degrees F or less
  7. Mulch before winter sets in

For a longer period of bloom, try planting crocus, hyacinth, tulip and daffodil - all early bloomers. Because the crocus are smaller - at about 4 inches tall - and are planted at a shallower depth than the other bulbs in the group, they'll emerge and bloom first. Next come the highly fragrant hyacinth at about 10 inches. These take a bit longer to develop, so they'll bloom a bit later. Larger tulips follow the hyacinth, and finally the tallest bulbs - the 16- to 18-inch daffodils - round out the season.

Planting by family also can provide a longer color period. If your client is a fan of one particular bulb, it's easy to lengthen the bloom season by planting early, mid-season and late-blooming varieties, sometimes of the same color. For a long-blooming pink tulip display, try combining early season 'Apricot Beauty', mid-season 'Pink Impression' and 'Angelique', which flowers in late spring.

Turning bulbs on their heads

Anyone who's ever planted a bulb knows the caveat: pointy side up. The bulb's flatter end, or basal plate, is where roots develop and the tapered end is where foliage, stem and flower emerge. So it only makes sense to plant roots down, (ultimate) foliage up - and in very small plantings, it's easy to remember and easy to do. But when bulb growers need to plant by the acre, it's next to impossible to place each and every bulb pointy side up. Yet, they survive and thrive.

So here's a little trick to creating a longer season of bloom by "fooling" bulbs when they're planted. Try this with multiples of the same variety: Plant about a third of the group in the traditional manner, basal plate down, pointy side up. These will emerge and bloom as expected. Plant the second group sideways, with the basal plate perpendicular to the bottom of the planting hole. This will force the bulb to right itself as the roots emerge - a phenomenon known as geo- tropism - and delay emergence and bloom by up to a week.

And here's the really fun part: Plant the rest of the bulbs upside down. As the bulb works to find its balance, bloom will be delayed by 10 to 14 days, giving one planting an extra few weeks of gorgeous color.

This works with all varieties of bulbs, unless your client insists on Fritillaria. This imperial bulb is oddly shaped, with a concave side that can collect moisture if it's placed incorrectly. Planting it upside down would only help it trap water, thus leading to rot. So if you're going to use Fritillaria imperialis, be sure to plant it on its side.

If yellow's a favorite, four tulip varieties provide an even longer color display. 'Monte Carlo' blooms early in spring, followed in mid-season by 'Yellow Impression'. Next comes 'Strong Gold', which flowers in late spring, and the very late blooming 'West Point' anchors the season.

Proper planting depth is critical to healthy bulb development, but it can also contribute to an extended season of color. Layering bulbs, which is a good trick for small gardens and large containers, creates a virtual bouquet of various bulbs that bloom in succession. For an in-ground application, dig a hole deep enough to accommodate the largest bulb, remembering the rule of thumb: Planting depth should be four times the diameter of the bulb. In general, a layered planting should be about 10 inches wide and about 8 inches deep, with sufficient drainage beneath the bulbs that are planted on the bottom layer.

For a colorful and fragrant bouquet, begin with early summer-blooming Allium giganteum at the very bottom of the hole or container. Cover the first layer with soil, then place tulips at a depth of about 6 inches. These will bloom in late spring. At 4 inches, place a group of early- to mid-spring Muscari (grape hyacinth), and finish with early crocus, planted about 3 inches deep.

Bulb culture

Bulbs are relatively easy to grow if they're provided with the right conditions and a little extra care to ensure a healthy environment. They're forgiving of many soils; in fact, they tolerate media high in sand, clay or peat. But the soil must be well-drained; because of their Mediterranean origins, bulbs don't like to be wet.

The pH should be neutral, and EC (salt concentration) should be no higher than 2. Iffy soils can be amended with coarse sand, but the challenge of soil quality can easily be met with container plantings. Bulbs thrive in containers.

Chilling is critical to bulbs' development; a period of cold is necessary to break through the plants' dormancy. The length of the cold period varies depending on the variety of bulb; for example, tulips need a longer chill than hyacinths. Ambient temperature during the flowering period also affects bulbs' performance, and higher temperatures can shorten the length of bloom. If spring temps average 60 degrees or less, flowering can last up to three weeks; at higher temps, say, above 70, the flowering period can be reduced to a mere week.

In general, winter temperatures will not damage spring-flowering bulbs, but that doesn't mean that they're not affected by extreme cold. If the mercury plummets and there's little natural snow cover, bulbs can freeze. An insulating layer of compost, mulch or leaves will help protect the bulbs until they emerge.

And here's a nifty little benefit to layered plantings: Grape hyacinth has repellent properties that make it unpalatable to critters known for their voracious bulb appetites. If a layer of Muscari is placed to encircle the planting, hungry pests likely will look elsewhere for their meal.

For an additional bloom-extending trick that borders on heresy, see the sidebar, "Turning bulbs on their heads."

Bulb gardens can provide reliable color from early spring through early summer. Try a few of these easy planting tricks and your clients will be hooked.

Ten golden rules for success

Easy to remember, easy to follow and easy to perform, these rules will help achieve bulb success.

  1. Buy early for the best selection and the freshest bulbs
  2. Remember that bulbs are heavy feeders and need fertilizers in spring and fall
  3. Make sure the location where the bulbs are to be planted is properly drained
  4. Soil texture is extremely important; bulbs have to breathe. Modify heavy clay
  5. Never plant the same kind of bulbs in the same location twice
  6. Plant when the soil temperature is below 50 degrees F; if the soil is too warm, remove the bulbs from plastic packaging and store them in a dry, well-ventilated location or in brown paper bags until soil temperature is appropriate is ready for planting
  7. Use repellents to protect from rabbits, deer, squirrels and voles
  8. If the soil is on the dry side when planting is done, moisten the soil and water the site after planting
  9. The proper planting depth means that there will be approximately 4 inches of soil placed on top of the bulb. Remember the rule of thumb: planting depth should be four times the diameter of the bulb
  10. Water once a week after planting if there is no rainfall

Jennifer Brennan is horticulture information specialist for Chalet Nursery in Wilmette, Ill., where she established the company's widely respected Education Series, which qualifies as certifiable course work for the Illinois Master Gardeners program. Often seen on local television programs in the Chicago area, Brennan received the 2009 Perennial Plant Association Media Award. Prior to joining Chalet, she served as staff horticulturist in the Plant Information Offices at the Chicago Botanic Garden. She can be reached at JenniferB@ChaletNursery.com.