Dahlia

Dahlia is a genus of bushy, tuberous, herbaceous perennial plants native to Mexico and Central America. The dahlia was declared the national flower of Mexico in 1963. Dahlias belong to the Asteraceae family, a group of flowering plants that also include popular garden favorites such as zinnias, daisies, and chrysanthemums. Dahlia consists of 42 species with hybrids which is commonly grown as garden plants.



The forms of flower are variable having one head per stem. Leaves are glaucous and glabrous beneath. Inflorescence is solitary, involucrate, long pedunculate and 10 to 20 cm across. Disc florets are actinomorphic, bisexual, tubular and five lobed. Ray florets are zygomorphic, several marginal rows. Fruit is an achene which is dorsally compressed with pappus being absent or shortly bidentate.


Table of Contents


Height(Avg)

1-6 feet


Width-Circumference (Avg)

1-3 feet


Approximate pH

6.5 - 7.0


Growth Nutrition of Dahlia


Dahlia grows better in high organic residues. Leaf mold, compost or FYM can also be used for good results. Dahlia like other plants needs NPK in large amounts and other elements like Fe, Zn, Cu, and Cl in small quantities. Nutrition is an important factor which is directly related to growth and flowering of dahlia.


Types of Dahlias


Dahlias come in many different patterns, textures, and colors—the types are innumerable. A few varieties take on different shapes and flower patterns and include the following:


Formal Decorative


Formal decorative dahlias are named for their evenly spaced and regularly placed petals, also known as “ray florets.” The petals are double and dense, with a tendency to have a slight curve back toward the flower’s stem. The petal edges may roll slightly forward (partially involute) or slightly backward (partially revolute).


Popular types of formal decorative dahlias include:

  • ‘Eveline’ has snowy white flowers with a lavender margin and a blooming season that lasts from July through frost.


  • ‘Hillcrest Firecrest’ has medium-sized, bi-color yellow and red flowers.


  • ‘Kelvin Floodlight’: A dinner plate dahlia with lemony blooms and slightly pointed petals.


  • ‘Rothesay Reveller’: A medium-sized flower that grows to 3 feet tall with purple and white petals.


  • ‘Barbarry Sultan’ has small flowers with dark pink to red petals.


Informal Decorative


Informal decorative dahlias look a lot like formal decorative, but their petals aren’t evenly and regularly spaced. Petals may be flat, twisted, curled, wavy, and partially revolute. The ray florets’ irregular spacing gives them an informal look.


Popular varieties of informal decorative dahlias include:

  • ‘Cafe au Lait’: A wildly popular and photogenic dinner plate dahlia with stunning, 10-inch flowers in creamy blush, peach, or beige.


  • ‘Crazy Love’ is a medium-sized dahlia with white petals around a yellow center, ray florets have a thin purple margin.


  • ‘Gitt’s Perfection’ boasts enormous, pale pink flowers that fade to a white center atop 4-foot-tall stems.


  • ‘Labyrinth’: A dinner plate dahlia with vibrant peach, pink and coral bi-color petals.


  • ‘Thomas Edison’ informal decorative dahlias have 8-inch purple flowers that bloom profusely.


Semi-Cactus


Semi-cactus dahlias are known for petals that are flat at their base, then revolute for less than half of their length. Petals may be straight, recurved, or incurved. Semi-cactus dahlias have double blooms.


Popular types of semi-cactus dahlias include:

  • ‘Black Jack’ has a large, 8-inch flower with pointy, deep red ray florets around an almost-black heart.


  • ‘Inca Dambuster’: A giant, yellow semi-cactus that reaches up to 10 inches in diameter.

  • ‘Veritable’: Grows up to 44 inches tall with medium white flowers with dramatic purple tips.


  • ‘Weston Stardust’ is an award-winning miniature semi-cactus with stunning red to yellow petals.



Straight Cactus

Petals are revolute for more than half their length, creating an almost “spiny” appearance. The ray florets may be straight, almost straight, pointed or recurved. They emerge from the flower head in all directions. Because the petals are rolled, they don’t collect water; this means they weight less and may not need staking.


Popular straight cactus dahlias include:

  • ‘Bora Bora’: Bright pink petals that fade to yellow at the center.


  • ‘Karma Sangria’ has salmon and yellow petals on a 6-inch bloom.


  • ‘Mingus Randy’: A giant dinner plate variety that produces lavender and white flowers.


  • ‘Tu Tu’ is a newer variety with spiky, double, pure white petals.


Incurved Cactus


Like the straight cactus dahlia, the incurved cactus also has petals that roll for more than half their length. Most look completely rolled, from the base to their pointed tip. However, the petals also curve inward toward the center of the flower.


Popular incurved cactus dahlia varieties include:

  • ‘Bed Head’ has small, 4-inch blooms in an eye-catching peachy coral hue.


  • ‘Hey Mom’: Giant, 10-inch flower heads with snowy white petals.


  • ‘Jungle Man’ stands up to 6 feet tall and has dark red, 7-inch flower heads.


  • ‘Northlake Heritage’ has pale, lemon yellow petals that make almost 90-degree turns for a unique look.


Laciniated


Laciniated dahlias are named for the split, or laciniation, found at the end of each petal. This gives them a frilly look, as though they were cut with pinking shears. The petals are uniformly arranged and may be involute or revolute.


Popular types of laciniate dahlias include:

  • ‘Myrtle’s Folly’: These unusual dahlias have pink, yellow, and orange petals that are so narrow that they twist, making them look fluffy.


  • ‘Northlake Pride’ has extremely narrow, bright red petals that create an eye-catching spiky appearance.


  • ‘Omega’ is a dinner plate dahlia with pink and yellow petals that twist and twirl.


  • ‘Urchin’ sports a deep red to purple hue and spiny-looking petals that make it resemble the sea creature it’s named after.


Ball


Not surprisingly, ball dahlias bloom in the shape of a sphere — though some varieties may have a slightly flattened face — and have fully double blossoms. Petals usually grow in a spiral pattern and may have blunt, indented, or rounded margins. Ray florets may be mostly involute for most of their length, or fully involute for half of their length.


Popular ball dahlia varieties include:

  • ‘Amy Cave’: This dahlia has deep red-purple petals, ringed in concentric circles on a 6-inch flower head.


  • ‘Bonanza’ boasts luscious raspberry and peach tones around a deep maroon center.


  • ‘Cornel’ has 4-inch-wide flowers with lovely, cherry-red petals arranged in neatly spiraling circles.


  • ‘Franz Kafka’: This award-winning dahlia offers 3-inch blooms in a dark pink honeycomb pattern that looks almost geometric in nature.


  • ‘Wine Eyed Jill’ is a smaller plant with miniature ball flowers, with tightly packed petals that range from palest pink to deepest burgundy at the heart.



Miniature Ball


Miniature ball dahlia also boasts sphere-like, fully double blossoms like the larger ball type. Petals can be indented, round, or blunt and may be partially or fully involute. They differ in size; miniature ball dahlias are smaller than their larger cousins.


Popular varieties of miniature ball dahlias include:

  • ‘Aurora’s Kiss’ adds darkest red to the garden, with small round blooms atop tall stems.


  • ‘Charlotte Bateson’: This miniature ball dahlia has rich pink petals, perfectly arranged in concentric circles.

  • ‘Downham Royal’ dahlias bloom in unusual deep-pink and purple mix that makes the small flowers look almost iridescent.


  • ‘Ruskin Tangerine’ brings the brightest orange, 2.5-inch flowers to the middle of the flower bed.


  • ‘Ryecroft Yellow Orb’: 3-inch balls of sunshine yellow bloom from summer through fall.


Pompon


Like ball dahlias, pompons have fully double flower heads. However, they’re even more globular in shape and smaller in size at only about 2 inches. Pompon petals may be partially involute for their entire length or fully involute for more than half their length.


Popular types of pompon dahlias include:

  • ‘Gillwood Violet’: This variety brings a hint of purple and lavender to the garden bed with 2-inch spherical blossoms and dark foliage.

  • ‘Martin’s Yellow’ has 2-inch bright yellow flowers that fade to lemon yellow at the margins atop 3-foot tall stems.

  • ‘Ms Kennedy’ has larger flowers than many pompon varieties and offers brilliant orange-yellow tones with an almost-pink center.


  • ‘Noreen’ has light pink petals that fade to almost white at the tips and a full, round appearance.


  • ‘Pensford Marion’: This variety has small, deep red-pink flowers that bring the hue of raspberries to mind.

Stellar


Stellar dahlias are fully double and characterized by gradating differences between immature and mature florets. Immature ray florets are narrow and partially involute, with maturing ray florets gradually growing more involute, all with a slight recurve toward the stem. Proportion is key, too, with an ideal depth being more than 2/3 to 1/2 that of the diameter.


Popular stellar dahlia varieties include:

  • ‘Alloway Candy’ boasts baby-pink blooms, making them a favorite for wedding parties and baby showers.


  • ‘Camano Pet’: This small, stellar dahlia has 4-inch flowers with buttery yellow petals and orange-pink margins.

  • ‘Felida Stars and Stripes’ is a showy, bi-color dahlia with dramatic red and white petals.

  • ‘Gitt’s Crazy’ sports large, 7-inch flowers in stunning shades of gold and fuchsia.


  • ‘Irish Pinwheel’ has strongly recurved golden petals that deepen to a cherry red center.


Waterlily


Waterlily double blooms and symmetrical placement, waterlily dahlias look flat from the side. Four to seven rows of outer ray florets surround a closed, dome-shaped center. Petals are usually broad, flat, or slightly cupped and often incurved somewhat to a depth of about one-third of the flower’s diameter.


Popular types of waterlily dahlias include:

  • ‘Creme de Cassis’ is a stunning variety with a deep burgundy center, surrounded by flat, broad light pink petals.


  • ‘Firepot’ offers a bright burst of color, with unusual bicolor petals of sunny orange and fiery red-orange.


  • ‘Gerrie Hoeck’: This popular dahlia is beloved for its tropical, dark pink hue.


  • ‘Happy Butterfly’ waterlily dahlias have cheerful, buttery yellow petals streaked with striking burgundy.


  • ‘Pearl of Heemstede’ has silver-pink, 8-inch flowers that contrast with its dark green foliage.


Peony


Unlike waterlily dahlias, peony dahlias have an open center and are single flowering. They also have two or more rings of petals around a disc of tiny, tube-shaped florets. Petals that grow around the disc are often curled, twisted, small, or otherwise irregularly shaped.


Popular peony dahlia varieties include:

  • ‘Bishop of Canterbury’: Offers a splash of magenta flowers that bloom late in summer.


  • ‘Bishop of Llandaf’ is a classic variety that boasts bright, cardinal red petals atop foliage so dark that it almost appears black.


  • ‘Bishop of Oxford’ also has deep, dark foliage but is topped with cheerful coppery orange blossoms.


  • ‘Fascination’: This peony dahlia is a semi-double variety with a bright pink hue and green-purple foliage.


  • ‘Waltzing Mathilda’: An award winner with purple foliage and 4-inch flowers that range from red and orange to yellow and coral.


Anemone


Anemone dahlias can be identified by rows of (usually flat) petals surrounding a densely petaled central disc. The disc is made of tightly packed, colorful, tubular petals that grow in a domed shape that resembles a pincushion.


Popular varieties of anemone dahlias include:

  • ‘Boogie Woogie’ boasts a bright orange-yellow pincushion, ringed by happy pink and mauve outer petals.


  • ‘Edge of Joy’: Slightly pointed, pale pink petals surround a deeper center for dramatic contrast.


  • ‘Paso Doble’ sports a yellow center surrounded by white petals and resembles a sunny side-up egg or a spring daffodil.


  • ‘Purple Haze’: A late-summer bloomer with bright magenta, 6-inch blossoms.


  • ‘Totally Tangerine’: Bright orange flowers surround a pink pincushion, all atop a sturdy stem.


Collarette


The collarette dahlia has a single row of flat or slightly cupped petals. A smaller ring of petaloids, less than half the length of the outer petals, rings the central disc.


Popular collarette dahlia types include:

  • ‘Mary Evelyn’ adds drama to the garden with strongly contrasting rings of burgundy, white and yellow.


  • ‘Night Butterfly’: Another striking cellarette, this dahlia boasts bright red outer petals around a ring of white streaked with pink.


  • ‘Pooh’ is named for the beloved bear, with rings of bright yellow and orange hues.


  • ‘Teesbroke Audrey’: Soft pastel pinks ring an inner layer of snowy petaloids around a central ring of sunny yellow.


  • ‘Twyning’s White Chocolate’ offers luscious white blossoms around a creamy, fringed petaloid ring.


Single


Single dahlias have a solitary row of petals surrounding a disc of tightly packed petaloids. This type of dahlia has ray florets that lie flat and are evenly spaced around the central disc. Petals may overlap, and colors often concentrate toward the center.


Popular varieties of single dahlias include:

  • ‘Bright Eyes’ features vibrant magenta petals that surround bright yellow centers, with upright stamens that attract pollinators.


  • ‘Hadrian’s Sunset’ is a compact variety with coral, bronze and orange flowers atop dark purple foliage.

  • ‘Mexican Star’: Deep burgundy petals surround a golden yellow center, filling the air with rich fragrance.


  • ‘Sunshine’: A small dahlia for the front of the border, with bright yellow-to-orange blossoms above fern-like foliage.


Mignon Single


Mingon single dahlias have the same characteristics as single dahlias — a single row of petals surrounding a disc — but have smaller diameters. Mignon single flowers grow to a diameter of 2 inches or less.


Popular mignon single dahlia types include:

  • ‘G. F. Hemerick’ dahlias produce coppery flowers with a yellow central disc from summer through fall.


  • ‘Pulp Fiction’ has bright red flowers atop deep purple foliage and only reaches about a foot tall.


  • ‘Scura’: Produces eye-catching tangerine flowers with deep orange centers; blossoms are only about in inch in diameter.


Orchid


Orchid dahlias feature one row (single) or two rows (double) of regularly spaced petals around a central disc. At least 2/3 of petal length is partially involute, and 1/3 of length is fully involute. Petals may overlap.


Popular types of orchid dahlias include:

  • ‘Honka Fragile’ has a single row of white, almost completely rolled petals with a very fine red margin.


  • ‘Honka Red’: This elegant dahlia has a single row of deeply involuted red petals, creating a star-shaped flower around a bright yellow central disc.


  • ‘Jescot Julie’ boasts 6-inch orange flowers with a deeper, darker underside.


  • ‘Pink Giraffe’: This award-winner has two rows of pale pink petals that involute to show their deep pink stippled undersides.


Orchette


Orchette dahlias combine characteristics of orchid and collarettes. Like orchid dahlias, 2/3 of orchette petal length is partially involute, while 1/3 of the length is fully involute. Like collarettes, the orchette has a petaloid-ringed central disc.


Popular orchette dahlia varieties include:

  • ‘Christmas Star’ has festive red petals that involute to show white undersides, around white petaloids.


  • ‘Rae Ann’s Antares’: Boasts swirls of violet and white around a snowy ring of petaloids.

  • ‘Rae Ann’s Volunteer’ looks like a white star, with a yellow disc framed by creamy ray florets or pure white.


  • ‘Verone’s Ele’ catches the eye with deep pink petals around a buttery yellow central ring of ruffly petaloids.

  • ‘Verone’s Morning Star’: Brightens the garden at dusk with pointed, starlike ray florets surrounding white petaloids.


Novelty Open


Novelty open dahlias don’t fit neatly into any of the other ADS classifications. They may have different characteristics but can be identified by an open, visible central disc.


Popular types of novelty open dahlias include:

  • ‘Apple Blossom’ is sought-after by wedding florists due to its soft, peachy blush tones that fade to buttery cream.


  • ‘Dad’s Favorite’: Lovely purple petals with rounded edges surround huge, golden flecked central discs.


  • ‘Hy Zizzle’ sports deep lavender ray florets and a puffy, frilly center in eye-catching gold and raspberry tones.


  • ‘Rock Star’ is saturated with color, thanks to brilliant cranberry and purple petals.


Novelty Fully Double


As their name suggests, novelty fully double also doesn’t fit neatly into the other ADS form categories. However, these dahlias have a fully double center.


Popular novelty fully double varieties include:

  • ‘Akita’ produces 8 to 10-inch flowers streaked with yellow, gold, bronze, and deep red.


  • ‘Bloomquist Pincushion’: Luscious purple petals with a voluminous appearance.


  • ‘Platinum Blonde’ have double white blooms surrounding a fuzzy, fluffy buttercream center.


  • ‘Polka’: Rows of white petals streaked with cranberry ring the frilly yellow petaloid at the flower’s center.


Planting Dahlias


Dahlias thrive in 6 to 8 hours of direct sun, especially morning sunlight. They benefit from protection from wind, as strong winds can blow over tall dahlias if they are not supported. Consider their size at maturity when planting.


Dahlias will do best in rich, well-draining soil with a pH level of 6.0 to 7.5. Amend heavy clay soil with aged manure or compost to lighten and loosen the soil texture for better drainage.


When to Plant Dahlias

  • Dahlias will not tolerate cold soil. Plant when the soil reaches 60ºF (15°C) and any danger of frost has passed.

  • Planting dahlias a few days after tomatoes are planted in the ground is a good rule of thumb.

  • Some gardeners start tubers indoors in containers a month ahead to get a jump on the season. Medium to dwarf-size dahlias will do well in containers.


How to Plant Dahlias

  • Avoid planting dahlia tubers that appear wrinkled or rotten. Pink “eyes” (buds) or a little bit of green growth are good signs.

  • Plant large dahlias and those grown solely as cut flowers in a dedicated plot where they will be free from competition from other plants. Set tubers in rows spaced 3 feet apart. If you plant dahlias about 1 foot apart, they make a nice flowering hedge and will support each other.

  • Plant medium- to low-height dahlias, usually in the 3-foot tall range, among other summer flowers. Set them 2 feet apart.

  • Plant the smallest bedding dahlias, grown from seed, 9 to 12 inches apart.

  • To plant the tubers, start by digging a 6- to 8-inch deep hole.

  • Set a tuber into the hole with the growing points, or “eyes,” facing up.

  • Do not break or cut individual dahlia tubers (as you would with potatoes).

  • Cover the tuber with 2 to 3 inches of soil. (Some say 1 inch is adequate.)

  • As the stem sprouts, fill in with soil until it is at ground level.

  • Do not water the tubers right after planting. This encourages rot. Wait until the sprouts have appeared above the soil, then water.

  • The planting hole should be slightly larger than the root ball of the plant and incorporate some compost or sphagnum peat moss into the soil. It also helps to mix a handful of bonemeal into the planting hole. Otherwise, do not fertilize at planting.


Growing Dahlias


How to Grow Dahlias From Seed


Dahlias can be grown from seeds purchased at your local nursery. or from seeds collected from last year's plants. To do so, first, fill a seeding tray with seed starting mix and sow seeds indoors, directly into this medium, four to five weeks before the last frost. Move the tray to a sunny window and keep the soil moist. Once sprouted, allow the seedlings to form one true set of leaves before transplanting each seedling into its own cell or small pot; keep the soil moist. Once outdoor soil temperatures reach 65 to 70° F, transplant the seedlings directly into an outdoor garden bed.


Growing Dahlias in Containers


Medium- to dwarf-size dahlias do well in containers that have drainage and are big enough to support the plant at maturity. Generally, a 12x12 inch container will suffice.

  • Use a soilless mix and co-polymer moisture-retaining crystals, per the package’s guidance.

  • Follow the depth requirements.

  • Cover the tuber with a few inches of soil-crystal mix.

  • Spray water on the tuber, if necessary, until growth starts.

  • Do not water if the soil is damp 1 inch below the surface.

  • Fertilize through summer as directed.

  • Add soil if the roots become exposed.


How to Get Dahlias to Bloom


Dahlias bloom best when the plant is not flopping to the ground, so be sure to use stakes and twine to keep them up and erect. Fertilize your dahlias every two weeks to allow flowers to proliferate. An organic fertilizer that is high in phosphorous will assure a good flowering rate and strong stems. Be sure to provide ample water for your dahlia bed, especially those containing large varietals, and mulch around the bottom to retain moisture. Lastly, make sure to deadhead your plants as soon as the flowers are spent. removing dead flowers promptly will encourage more blooms.


Dahlia Care


Stunning dahlias are actually fairly easy to grow. Grown from tubers, not bulbs, you can start dahlias indoors in early spring, and then plant them outdoors once the danger of frost has passed. Or, you can wait until the soil has warmed in the spring, and then plant the tubers directly outdoors. Plant tubers two to six inches deep, depending on variety. The plants need good air circulation to thrive, so place smaller varieties about 12 inches apart and large cultivars up to three feet apart. Regardless of where you grow them—in the ground or in containers—plant tubers in an area that receives full sun, water them regularly, and fertilize them promptly when new growth appears.


Dahlias require the one-time task of pinching off the tops, once the tubers have sprouted and formed branches. Wait until three sets of branches appear, and then top the stem just above the highest set of branches. This pruning tactic encourages the plant to grow more branches, thus creating more blooms. Within months, you'll be treated to a garden full of stunning, colorful, and oversized blooms. Just be sure to deadhead faded blooms to keep the plant looking tidy and to encourage flowering.


Light


In order to produce abundant blooms, dahlias require full sun, preferably at least 6 to 8 hours a day. In climates more similar to their native growing zone