Archives For growing dahlias

What is it about dahlias?

Guest Blogger —  September 7, 2017 — 1 Comment

When it comes to showstoppers, Shakespeare may have elevated the rose to star status with his line, “Of all the flowers, methinks a rose is best.”

But what is it about dahlias that has attracted so many fans and admirers? In our effort to describe the joys of dahlia gardening, members of Central States Dahlia Society were recently asked why they are so enthusiastic about these dramatic floral divas, which will be on display September 9-10 at the Chicago Botanic Garden. Here’s what we found.

Dahlia 'Hollywood Spiderwoman'

Dahlia ‘Hollywood Spiderwoman’

Dahlia 'Hissy Fitz'

Dahlia ‘Hissy Fitz’

Dahlia 'Harvey Koop'

Dahlia ‘Harvey Koop’

Size does matter.  Of the 70,000 varieties developed, dahlia blooms range in size from the miniatures, just 12 inches tall with 2-inch blooms, to the huge “dinnerplates,” the dense, glossy-leaved plants that grow up to 6 feet tall and bloom with flowers 10 to 12 inches in diameter.  As one member said:  “I love giant flowers! The ‘dinnerplates’ are showstoppers!” Another praised the benefits of smaller varieties, which can be used in containers when space is limited. “Sometimes, you don’t realize they are all part of the same family,” she said.

Miniature dahlias sport 2-inch blooms

Miniature dahlias sport 2-inch blooms.

A "dinner plate" dahlia

A “dinnerplate” dahlia…

A "dinner plate" dahlia

…can measure up to a foot across!

They come in a range of colors. Color and beauty ranked high in members’ reviews. The wide range color range means dahlias will complement any gardening color scheme and co-star with both annuals and perennials in a garden. Recognized by one member as “The Las Vegas of flowers,” dahlias range from the darkest red or purple to many shades of pink, orange, yellow, and white. There are also blends, variegated, and bi-colored cultivars. The only color missing from this palette is blue. Many admired the range of color in the foliage as well. 

Informal dahlia arrangement

Informal dahlia arrangement

Informal dahlia arrangement

Informal dahlia arrangement

Informal dahlia arrangement

Informal dahlia arrangement

Formal dahlia arrangment

Formal dahlia arrangement

These prolific bloomers offer a lot of choices. Form and size are categorized by the American Dahlia Society (www.dahlia.org) into 21 classifications, and members are drawn to the diversity, describing the blooms as “gigantic,” “elegant,” and “perfection.” The plants provide continuous blooms from July to frost. As a cut flower, dahlias are superstars. The more you cut them, the more prolific they become.

Formal decorative form dahlia

Formal decorative form dahlia

Pompon form dahlias

Pompon form dahlias

Incurved cactus dahlia form

Incurved cactus dahlia form

Code Description
AN Anemone-flowered
BA Ball
Straight Cactus
CO Collarette
FD Formal Decorative
IC Incurved Cactus
ID Informal Decorative
LC Laciniated
MB Miniature Ball
MS Mignon Single
Novelty
NO Novelty Open
NX Novelty Fully Double
Orchid-flowering 
OT  Orchette 
Pompon
PE Peony-flowering
Single
SC Semi-Cactus
ST Stellar
WL Water Lily 

Copyright ©1995-present, American Dahlia Society, all rights reserved.

Other members cited the unique features of dahlias. There are 1,500-plus named varieties, with names like Prince Charming, Blondee, Cutie Patootie, and Diva. The availability of low-growing varieties makes them perfect for containers. While dahlias receive a standing ovation for their color and form, they have no scent, making them an ideal bloom for people with allergies.

Devoted followers highlighted ease of growing as an attribute. Tubers can be saved and propagated from year to year, making them very efficient.

Then there is the “wow” factor. Our members found a special place in their hearts for these plants, like old friends, that deliver on their promise. Whether it is the opportunity to share the beauty and harvest of the garden with family, neighbors and friends, the occasion to find personal happiness or endure sorrow, or the chance to compete with other gardeners for the perfect bloom, dahlias provide a formidable scene. Dahlias offer something for everyone. In the words of the Bard, “One touch of nature makes the whole world kin.”

P.S.  Will, what were you thinking? The rose has thorns! Pick dahlias!

Dahlia arrangement at the Central States Dahlia Society Show

Join us September 9-10, 2017, for the 51st Central States Dahlia Society Show.

ILLUSTRATION: dahlia artWe hope you will join us at the 51st National Dahlia Show hosted by the Central States Dahlia Society at the Chicago Botanic Garden on September 9-10, 2017. For additional information on the Central States Dahlia Society or the 2017 National Dahlia Show, visit centralstatesdahliasociety.com/2017-national-show.

 

By Andrea Basalay, with thanks to the CSDS members for sharing their thoughts and experiences.


©2017 Chicago Botanic Garden and my.chicagobotanic.org

How to Grow More Amazing Dahlias Than Your Neighbors

A Dahlia Primer: From Planting to Blooming

Guest Blogger —  August 4, 2017 — 1 Comment

Get ready for an explosive burst of color September 9-10 at the annual American Dahlia Society National Show at the Chicago Botanic Garden. More than 2,000 flowers in the dahlia family will be on display in a wide variety of colors, sizes, and forms. 

Dahlias are indigenous to Mexico, where they were grown by the Aztecs, who used the tubers as one of their staple foods. The plants were brought to Spain and eventually spread throughout Europe, as people appreciated the beauty of the flowers themselves. Through hybridization, there now are more than 70,000 varieties of dahlia, about 1,500 of which are popularly grown.

Here are some tips for growing these beautiful plants in the garden. 

Dahlia bouquet from the American Dahlia Society National Show

ILLUSTRATION: dahlia artOn September 9 and 10, the Central States Dahlia Society and the Chicago Botanic Garden present the 51st annual American Dahlia Society National Show. For detailed information on the show and the Central States Dahlia Society, please visit centralstatesdahliasociety.com


Selecting a site

Pick a sunny spot where, optimally, the plants will receive at least six hours of sunlight. Since dahlias do not like to get their “feet” wet, the area should not accumulate water and should drain well. If the soil is clay-like, it should be amended with leaf mulch, compost, or peat moss. Since dahlias should be planted about 18 inches apart, it is easy to determine the number of plants the area will accommodate.

Planting

You can plant your dahlias as soon as the danger of frost has past, and the soil temperature remains above 55 degrees Fahrenheit. In Chicago, this typically means about the middle of May. However, some growers wait until Memorial Day just to be sure. The delay does not seem to appreciably affect when the first blooms appear. You can start with either potted plants or tubers that have been over-wintered from last year’s crop.

If using potted plants that have already developed a root system, place the plants in the ground so that the top of the potting medium is level with the ground. Many growers will add a slow-release fertilizer (e.g., Osmocote) and/or composted manure to the bottom of the hole. Water the plants once they have been put in the ground, and water as needed to keep the soil moist (about one inch per week).

Planted dahlia tuber

Planted dahlia tuber

A new dahlia plant

A new dahlia plant

When starting with tubers, dig a shallow hole (about 6 inches deep), add material as described above, and place the tuber on its side. Loosely cover the tuber—but do not bury it—with soil. Once the tuber has sprouted and the sprout has reached the level of the soil, the hole should be back-filled. The tubers should not be watered until they have sent out a sprout that reaches above ground level. A word of caution: Tuber sprouts can be quite delicate. It is a good idea to use a short, temporary support until the plant becomes established. You can start with tubers planted directly in the soil or start the tubers indoors in pots to get an early start. If starting inside, the tender plants should be “hardened” off prior to planting in the garden.

Since dahlias will often grow to five feet or more in height, they need to be staked. The stake should be placed in the ground as soon as the plant, or tuber, is in place. Put the supporting stake within a couple of inches of the plant and avoid damaging the tuber. Plastic stakes tend to bend and break. Many growers use ¼- to ½-inch rebar that can be bought from big-box stores or building supply centers. Tomato cages also provide good support.

New dahlia plant staked, tied, and identified

New dahlia plant staked, tied, and identified

Depending on the height of the plant, you should loosely tie it to the supporting stake. The final step in the planting process is to write the name of the variety on a plastic tag. The tag should be stuck in the ground or attached to the support system.

Dahlia bed ready for the growing season

Dahlia bed ready for the growing season

The first several weeks

As the plant continues to grow, additional ties will have to be placed at about 12-inch intervals. After the plant produces three or four sets of leaves and is about 18 inches tall, the plant should be “topped.”  This means that the terminal bud, at the top of the main stem, must be removed. This will be done only once. This process forces that plant to develop lateral stems, which results in more flowers. 

A "topped" dahlia with terminal bud removed, and laterals forming

A “topped” dahlia with terminal bud removed, and laterals forming

Water as needed to keep the soil moist. During this early phase, many growers will use a nitrogen fertilizer to promote leaf growth and stimulate the plant’s development.

Once buds appear

Depending on the weather and maturity of the starting stock, after about six to eight weeks the first buds should appear. These will develop in groups of three. Two of these should be removed. This process, called “disbudding,” will result in larger blooms. The first blooms tend to be the largest ones that the plant will produce. Growers who plan to compete in shows will try to time these first blooms so they appear just before the show.

A dahlia plant ready for "disbudding"

A dahlia plant ready for “disbudding”

During this phase, water the plant as needed. Watering should be done at the base of the plant. Water on the leaves may cause disease, and water on the blooms may cause them to become top-heavy and droop, or even break. Fertilizing during this phase should consist of potassium and phosphorus to encourage root and bloom development. Do not “over-feed’ the dahlias. Fertilizing about every three to four weeks is the generally recommended practice.   

If the plant becomes too full, you should remove a lateral stem or two. This process, called “disbranching,” should be done as close to the main stem as is possible. All plant grooming should be done in the early morning.  Ideally, you should sterilize the cutting tool as you move between plants to avoid the possible transfer of any disease for one plant to the next.

During the growing season, be aware of the impact of pests and plant disease. Snails and slugs may attack the newly planted dahlias. Spider mites are the most common pest. If they attack, the leaves will shrivel and yellow spots will appear. Many growers will preventatively spray once the hot weather arrives to avoid these pests, as remediation is difficult.

A garden full of dahlias

The fruits of your labor

Cutting the blooms

It is best to cut the blooms in the morning using a sharp instrument to make a clean cut. The stem can then be slit along its length to increase water absorption. Freshly cut dahlias will last in the house for one week or longer. 

 

By George Koons, Central States Dahlia Society


©2017 Chicago Botanic Garden and my.chicagobotanic.org