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  • Frances Palmer’s garden of dahlias in full bloom. Photo by: Frances Palmer.
  • Palmer’s garden in September, filled with dahlias at the peak of bloom. Photo by: Frances Palmer.
  • Another view of the garden with the smaller pom pon dahlias in front. Photo by: Frances Palmer.
  • Palmer’s dahlias in their full glory-if the flowers are cut for vases after they open, the plants will continue to bloom until the first frost. Photo by: Frances Palmer.
  • “Dahlias are fun to grow and once you get the hang of it, really quite easy,” says Frances Palmer. Photo by: Frances Palmer.

With their intense color, vigor, and ability to keep flowering until the first frosts, dahlias are invaluable for bringing life to your garden. Dahlias like well-balanced & composted soil, and full sun. Dahlias are generally winter hardy in zones 7-10 (except for isolated areas that may get below freezing) and can stay in the ground. In these marginal areas or colder zones, dahlia tubers should be dug up and stored over winter.

DAHLIA FACTS

Zones:

Generally winter hardy in zones 7-10. In colder zones, tubers can be dug up and stored for winter and re-planted in Spring, 1-2 weeks before last frost.

Height/Spread:

1-6 feet/1-3 feet

Exposure:

Full sun

Soil:

Well-balanced, organically rich

Water:

Medium

Color:

Varieties include red, pink, lavender, purple, orange, yellow, and white

Bloom Time:

July to September

Tomato cages and wooden stakes can be used to support dahlias. Photo by: Frances Palmer.

7 STEPS TO GROWING GORGEOUS DAHLIAS

According to Frances Palmer, well-known potter and dahlia enthusiast, May is a good time to plant dahlia tubers. Here are instructions for planting:

  1. Place growing cages (tomato cages work well) in the soil and drive in 2-3 stakes adjacent to them for support.
  2. Dig the hole:
    For new or single tubers: Place them in a fairly shallow hole, approx. 3 inches deep, with the new bud facing up. Gently cover with dirt.
    For larger groups of tubers: Place in a deeper hole, keeping them approx. 3 inches below the surface.
  3. Attach a label to the cage for identification.
  4. Do not water, as there should be enough moisture in the soil this time of year. Over-watering causes tubers to rot.
  5. The first leaves should poke through the surface in about 1-2 weeks. When the first set of leaves is about 8-12 inches high, pinch out the center bud to encourage multiple stems to grow and produce more flowers.
  6. Bone meal or a mixture of 2 parts bone meal to 1 part sulfate of potash can be applied 2-3 times between June-October to encourage blooming. If your soil is healthy, this may not be needed at all.
  7. As your dahlias grow, gently encourage the stems to stay inside the cage for support. Garden twine can be tied around the outside for additional support.

DAHLIA PICTURES

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Photo by: Andrea Jones.

‘SASSAFRASS’

Height: 4 feet

Flower form: Laciniated, Cactus

Bright-gold, 6-inch-wide blossoms with deeply cut petals, ‘Sassafrass’ was introduced in 2010, derived from ‘Cheyenne’, which has streaks of pinkish-red.

Photo by: Andrea Jones.

'GIGGLES'

Height: 3-4 feet

Flower form: Collarette

Three-inch plus flowers are light orange with a very pronounced and faintly purple-flushed collar—an unusual and striking combination. Noted as a particularly prolific bloomer.

Photo by: Andrea Jones.

'BEE HAPPY’'

Height: 3 feet

Flower form: Collarette

This 4-inch-wide flower is bright pink with burgundy tones towards the center. The color is wonderfully complemented by the almost- lack leaves and stems, making it a compelling garden plant or even one for a larger container.

Photo by: Andrea Jones.

'GINGER SNAP'

Height: 4 feet

Flower form: Waterlily

The beauty of this variety is the way it gently fades from gold-yellow in the center to a light peach around the edges. Producing relatively small flowers from side branches on a compact plant, it’s good for cutting.

Photo by: Andrea Jones.

'SMARTY PANTS'

Height: 3 feet

Flower form: Decorative

The rich coral of this variety reflects the contemporary interest in combining dark foliage with strongly colored flowers. Tends to bloom early and form bushy plants. Its long flower stems make it good for cutting.

Photo by: Andrea Jones.

'LUCKY DUCKY'

Height: 4 feet

Flower form: Anemone

Three-inch-wide flowers in a uniform soft yellow with a prominent pincushion center; the surrounding ray petals tend to bend back as the flower ages. The plant grows with a distinctly upright habit.

Photo by: Andrea Jones.

'TINY TREASURE'

Height: 3-4 feet

Flower form: Pompon

A virtually pure-white variety. The inch- to inch-and-a-half-wide flowers have strong but rather short stems for cutting; however, the plant’s compact habit and relatively low height make it a good border plant.

Photo by: Andrea Jones.

'TUTTI FRUTTI'

Height: 4 feet

Flower form: Cactus

This variety has 5-inch fuchsia flowers and distinctly quilled petals. Blooms are produced on lateral shoots (side shoots), which means that there are plenty for cutting.

Photo by: Andrea Jones.

'CRAZY LEGS'

Height: 4 feet

Flower form: Stellar

The 3-inch-wide flowers are distinguished by the red reverse to the bronze petals. It is noted as a prolific bloomer with strong stems on a plant with handsome foliage.

Photo by: Andrea Jones.

'LAUREN MICHELLE'

Height: 4 feet

Flower form: Waterlily

Three-inch-wide lavender flowers with a darker center and reverse to the petals. Flowers are plentifully produced at a 45-degree angle from the plants. They last especially well in the vase.

DIGGING UP AND STORING TUBERS FOR WINTER

Dahlia tubers can be stored for the winter in your basement or garage. Photo by: Frances Palmer.

If you live in an area that will require you to store your dahlia tubers over winter, here are some helpful instructions:

  1. After the first frost, flowers & stems will immediately wilt. Leave them in the ground for a week or 2 after a few more strong frosts have occurred.
  2. Pull out support cages and/or stakes.
  3. Dig outside the circumference of the tubers with a pitchfork. The larger the plant, the larger the tuber; but don’t worry - if tubers are broken apart or damaged during digging, this will not damage the plant.
  4. Cut off dead stems 2-3 inches above the tuber bunch to give yourself something to hold onto, and gently shake off as much dirt as possible.
  5. Place a tag on the cut stem for identification.
  6. Place a few inches of peat moss or wood shavings in the bottom of a large cardboard box.
  7. Give the tubers a final shake to remove any further dried dirt, and layer them in the box with larger tubers on the bottom. At about half-way full, add another layer of packing material and more tubers. Cover completely with the storage material, shake to settle and top off with more storage material. Fold flaps to close.
  8. Store in a cool basement or garage that gets to about 40 degrees, but not below freezing.

DESIGN WITH DAHLIAS

The lower stems of dahlias tend to be unattractive and the plants have a heavy quality, so that without staking, they tend to flop. Distributing them amongst other plants helps support their weight and hides their lower stems. The taller varieties will grow well with perennials and ornamental grasses toward the rear or center of borders, while the shorter ones mix well with annuals or shorter perennials. The smallest make good container plants.

Magenta ‘Ambition’ and deep-red ‘Nuit d’Eté’ dominate this late-season border; blue Aster x frikartii ‘Mönch’ and gladioli play supporting roles. These late bloomers pick up where summer-flowering plants leave off, giving the garden a grand sendoff for winter. Photo by: Marianne Majerus.

Dahlia flowers inject strong color into a planting, so when choosing them it helps to think about what other flower or foliage colors there are going to be, as the dahlias will pick these up and echo them loudly. Other late-flowering perennials are always a good match, particularly if colors relate but form and texture are different, as with yellow dahlias and fluffy goldenrods, or purple-toned dahlias and asters in purple-blue shades. They can also look surprisingly good with grasses as the contrast is total—big solid exuberant flowers against finely textured shapes and colors too subtle to offer any competition. In more formal settings, their strong colors can be wonderfully enhanced by the cool foliage of clipped hedges.

By September, dahlias will be in their full glory. Good cutting dahlias tend to be the larger varieties because of their longer stems. If you cut for use in vases after they open, dahlias will continue to bloom until first frost.

However they are used, dahlias help the garden end the year on a high note.

WHERE TO BUY DAHLIAS

Frances Palmer’s recommendations for ordering dahlia tubers:
Endless Summer Flower Farm
Fern Cliff Gardens
Old House Gardens
Dahlias.com

RELATED:
Summer Arrangements: Sunflowers, Zinnias, and Dahlias
Summer Flowering Plants

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