Semi-Double Flowering Plants – Learn About Flowers With Semi-Double Blooms
By: Mary H. Dyer, Credentialed Garden Writer
What is a semi-double flower? When it comes to growing flowers, it can be difficult to sort through the various terminology and nearly countless ways of describing blooms. Understanding what growers mean by “single” and “double” blooms is fairly straightforward but the term “semi-double blooms” is slightly more complex.
Single, Double, and Semi-Double Petals
Let’s explore the concept of semi-double flower plants, along with a few tips for identifying a semi-double flower.
Single flowers are comprised of a single row of petalsarranged around the center of the flower. Five is the most common number ofpetals. Plants in this group include potentilla,daffodils,coreopsis,and hibiscus.
Flowers such as pansies,trillium,or mockorange generally only have three or four petals. Others, including daylily,scilla,crocus,watsonia,and cosmos,can have up to eight petals.
Bees prefer single flowers, as they provide more pollen than double or semi-double blooms. Bees are frustrated by double flowers because the stamens are often not functional or are hidden by the dense petals.
Double and semi-double flowers
Double flowers generally have 17 to 25 petals radiatingaround the stigma and stamen in the center of the plant, which may or may notbe visible. Double flowers include lilacs,most roses,and types of peonies,columbine,and carnations.
Double flowers are actually abnormalities, but herbalists ofthe Renaissance period recognized the beauty of the blooms and cultivated themin their gardens. Sometimes, double flowers are flowers within flowers, like daisies.
Semi-double flowering plants have two to three times morepetals than typical single flowers, but not quite as many as double blooms –generally in two or three rows. Unlike many varieties of double flowers,semi-double petals allow you to see the center of the plant.
Examples of semi-double flowers include gerberadaisies, certain types of asters,dahlias,peonies, roses, and most types of Gillenia.
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1. New Dawn
If you're looking for a fast grower, New Dawn won't disappoint. It can easily reach maturity within two seasons. This rose is considered a classic and has been grown in gardens for nearly a century.
This rose produces double blooms in soft pastel pinks that mature into 3" wide cream-colored displays. With dark green leaves, these roses are prolific with abundant clusters ideal for instant bouquets.
- Zones: 5-9
- Height: Up to 20'
- Spread: 8'-10'
- Sun: Plant in sun or shade good choice for Northern exposure
- Flower color: Light pink to cream
- Bloom time: Spring to first frost
- Fragrant: Yes
- Repeat bloomer: Yes
Best Place to Plant
New Dawn is a great choice for an arch, wall, pergola, fence, or pillar. The double clusters of roses create a very pleasing tumbling and cascading effect. You'll need to provide protection for this plant during the winter.
Cherished for their exquisite beauty, rich hues, and delightfully distinct variations, chrysanthemums are in a class—or rather 13 classes—all their own. Complex by nature, chrysanthemums are divided into 13 classifications, each representing a distinct flower form. Even a chrysanthemum flower itself is intricate and multifaceted, as each is composed of hundreds of florets, or small flowers. All complexities aside, the simple truth is this: as part of Blooms & Bamboo: Chrysanthemum and Ikebana Sogetsu Artistry, gorgeous representations of each of the 13 chrysanthemum classifications are on display now in our Conservatory … and here’s where you can find them.
Class 1: Irregular Incurve
Representing the largest blooms within the chrysanthemum genus, irregular incurve classification applies to those with florets or petals that loosely incurve and close the center. Lower florets present an irregular, or informal, appearance and may give the chrysanthemum a skirted effect. Our radiant Chyrsanthemum × morifolium ‘Seiko’ that make up our pagoda shapes in the East Conservatory represent the irregular incurve classification.
Chrysanthemum x morifolium 'Seiko', representing the irregular incurve classification. Photo by Cathy Matos.
Shaped like a flattened globe, chrysanthemums with the reflex classification have florets or petals that curve downward and overlap, similar to bird plumage. The exceptionally vibrant Chrysanthemum × morifolium ‘Domingo’ is a beautiful representation of the reflex classification and can be found in our Main Conservatory on the western side of the Exhibition Hall.
Chrysanthemum x morifolium 'Domingo' of the reflex classification. Photo by Amy Simon Berg.
Class 3: Regular Incurve
Regular incurve chrysanthemums feature a true spherical bloom equal in breadth and depth. These well-balanced beauties have petals that smoothly incurve and form a ball shape, curving tightly up. Chrysanthemum × morifolium ‘Gillette’ on the eastern side of our Exhibition Hall serve as a beautiful example of this classification.
Chrysanthemum x morifolium 'Gilette' of the regular incurve classification. Photo by Zach Longacre.
Chrysanthemum × morifolium ‘Indian Summer’ is not only a bronze showstopper along the southeastern walkway in our Main Conservatory but also an example of decorative chrysanthemum classification, thanks to its flattened bloom with short florets or petals. The upper florets incurve, while the lower petals curve outwardly, though not as much so as those within the reflex classification.
Chrysanthemum x morifolium 'Indian Summer' of the decorative classification. Photo by Candie Ward.
Class 5: Intermediate Incurve
Similar to the irregular incurve, the intermediate incurve classification is smaller than its counterpart, with shorter florets that only partially incurve with full centers. It also features an open appearance, as its petals are arranged more loosely. One such chrysanthemum is Chrysanthemum × morifolium ‘Le Mans’, a stunning pink flower that can found in our East Conservatory.
Chrysanthemum x morifolium 'Le Mans' of the intermediate incurve classification. Photo by Zach Longacre.
Pompon is a particularly fun classification, characterized by small, spherical blooms that are somewhat flat when young but fully round when mature. As the name suggests, petals curve either upwards or downwards in a round, globular shape. These whimsical blooms are popular in cut-flower displays, and size ranges from small button types to large disbudded blooms measuring almost four inches in diameter.
Chrysanthemum x morifolium 'Kermit' of the pompon classification add an unexpected touch to the East Conservatory. Photo by Cathy Matos.
Class 7: Single & Semi-Double
You may be fooled by single & semi-double chrysanthemums this classification produces blooms reminiscent of a daisy, with petals extending outward around a circular center. You’ll find several of these chrysanthemums in our Main Conservatory, including the luminous Chrysanthemum × morifolium ‘Icey Isle’.
Chrysanthemum x morifolium 'Icey Isle' of the single & semi-double classification. Photo by Cathy Matos.
If you’d like to see a variety of anemone chrysanthemums, then you’re in luck. These chrysanthemums are showcased in the form of columns, baskets, spirals, and ball standards, in hues of red, yellow, bronze, and pink. Anemone chrysanthemums also have a daisy-like appearance, but with a large center disk that can range from flat to hemispherical.
Representative of the anemone classification, Chrysanthemum x morifolium 'Heyward Horry' lends plenty of pops of pink to the Main Conservatory. Photo by Cathy Matos.
This aptly-named classification features spoon-like petals that face upwards, radiating out from a round center disk. Interesting and playful, these flowers are extremely textural thanks to their many rows of petals.
Chrysanthemum x morifolium 'Redwing' of the spoon classification can be found along the northwestern walkway of our Main Conservatory. Photo by Zach Longacre.
Chrysanthemums with the quill classification lack an open center, but make up for it in their straight, tubular florets or petals that push out from the center of the flower. The tips of the “quills” can be closed and pointed to open and flat. Chrysanthemum × morifolium ‘Seaton’s Ashleigh’ features breathtaking purple quills and can be found in the East Conservatory.
Chrysanthemum x morifolium 'Seaton's Ashleigh'. Photo by Cathy Matos.
Chrysanthemums of the spider classification lend multi-faceted visual interest, thanks to their long tubular ray florets that may coil or hook at the ends. The petals can be thin or thick in width. Our Main Conservatory boasts plenty of blooms that fall within the spider classification.
Chrysanthemum x morifolium 'Lava' flows in our Main Conservatory. Photo by Amy Simon Berg.
Class 12: Brush or Thistle
Chrysanthemums classified as brush or thistle can resemble an artist’s paintbrush, or feature fine, twisted tubular florets that appear flattened. Petals stick either up or out. Our Chrysanthemum × morifolium ‘Fluffy’ on the eastern walkway of the Main Conservatory represents this classification.
Chrysanthemum x morifolium 'Fluffy' in our Main Conservatory. Photo by Zach Longacre.
Class 13: Unclassified or Exotic
Blooms in the unclassified or exotic category may exhibit characteristics of more than one bloom class or are considered distinctive and unique, and therefore do not fall into any other category. You’ll find stunning examples of this classification in both our East and Main Conservatory.
Chrysanthemum x morifolium 'Edo 25' mystifies in our East Conservatory. Photo by Zach Longacre.
If you’d like to see all 13 classifications together in one place, our classification display in the Fern Passage is the perfect place to compare and contrast each type. Behold these beauties in person during Blooms & Bamboo: Chrysanthemum and Ikebana Sogetsu Artistry, on view now through November 17.
Growing Peonies Without Supports
Have you always wanted to grow peonies, but hesitated because you saw floppy ones everywhere, and didn't want to stake them? Try "landscape" peonies. So named because they don't require staking.
There are numerous peonies that do not require staking. They are referred to as "landscape" peonies. Let's explore them and see how you can bring some of these low maintenance beauties to your garden.
One thing to bear in mind when purchasing peonies is that active hybridizers will often take a classic peony that is quite inexpensive ($16 to $18) and give it a minor genetic spin (which may or may not make it better) so that they can command a premium price for it (usually ten dollars more). My advice would be to go with the classic peony, which is widely available, tried and true. In the interest of economy, I am eliminated itohs and intersectionals (crosses between tree peonies and lactiflora peonies) since they are priced at anything from $50 to close to $200.
Peony lactiflora 'Bowl of Beauty'
Hybridized by in 1949 By "hoogendoorn" 'Bowl of Beauty', which is hardy from zones 3-8 has large anemone shaped blossoms, as much as 8 inches wide. It is wonderfully fragrant and makes an excellent cut flower. It blooms early in the season. Since it is 2 to 3 feet high and wide, it should be spaced accordingly. It thrives in full sun to light afternoon shade. The blossoms can be quite large: 9" to 10″ across, sometimes more.
It is a very reliable peony, with strong stems. A multiple award winner, it also has a wonderful fragrance, and is a popular cut flower.
Peony lactiflora 'Krinkled White'
Hybridized by Archie Brand in 1928 and considered one of the finest of all white single peonies, award-winning Peony 'Krinkled White' features large blossoms with crepe paper-like, crinkled petals surrounding a tuft of golden stamens in their center. Slightly fragrant, the flowers are borne in profusion, thanks to the presence of many buds. It is tall and erect and is considered to have very desirable from. It opens light pink. It is a proven performer in the south, in places like Louisiana, while showing excellent form in cold climates.
With a height and spread of 2 to 3 feet, and blooming in full to partial sun, this is a very popular peony for cutting. It too has won multiple awards.
Peony 'Burma Ruby' or 'Burma Joy'
Burma Ruby, hybridized by Glasscock in 1928, is a hybrid single. Hardy in zones 2 to 8, in appearance, it is very much like a supersized oriental poppy. Height and spread are both 2 to 3 feet. There are very similar cultivars, namely Burma Joy and Burma Midnight, the latter hybridized by Klehm in 1994. If this peony is to your taste, you should feel comfortable ordering whichever is most available to you. Do note that the original is a Gold Medal winner and still considered one of the best reds. It too blooms in full sun to partial shade. It has won the Award of Landscape Merit, and is reliable and vigorous.
This is Burma Joy, from my garden.
Peony 'Coral Sunset'
Among the first peonies to bloom in spring, this series of peonies to which this belongs introduced a new color to the genus. Hardy in zones 3 to 8, the height is of 2.5 to 3.5 feet, with a spread of 2 to 2.5 feet. Coral pink with gold centers, like most peonies, it requires full sun to part shade. There are a series of coral peonies, from Pink Hawaiian Coral, Coral Sunset to Coral Charm. One thing to bear in mind is their vigor. I went to Janesville, Wisconsin for a peony conference, and we were taken to the fields of Roy Klehm, whose family has been growing peonies for three generations. Karl J. Klehm, perhaps the preeminent hybridizer until he retired in April of 2019, took us to a field of Pink Hawaiian Coral peonies that stretched pretty much as far as the eye could see.
Lesson of the story - this peony is extremely vigorous.
It was hybridized in 1981 by Samuel Wissing and Roy G. Klehm, and won many awards. It possesses large, semi-double, ruffled flowers that open smoldering coral with rose-pink highlights and mature to pale apricot with golden-yellow stamen centers. It is lightly fragrant.
Peony 'Bride's Dream'
Hybridized by William Krekler in 1965, this is a white Japanese style peony that is hardy in zones 5 to 8. This is a rather different looking peony in that it has a large number of thin petaloids that fill the center.This plant is 2 and a half to 3 feet tall and wide. It stands up well to the elements, including rain. It is reliable and vigorous, and has a large number of side buds, which substantially increases the length of the blooming period.
Peony 'Sea Shell'
Introduced in 1937, by William Sass. I will let the Old House Gardens website speak for this one:
'Sea Shell’ produces a flurry of big, soft pink, single flowers on sturdy stems, each illuminated by a heart of yellow stamens."
The lilac-pink single blooms born over a very long season as side buds extend the season. Hardy in zones 3 to 8, and growing in full to partial shade, it makes a wonderful cut flower. 3 to 4 feet tall, and 2 to 3 feet wide, it is very free-flowering and quite vigorous. Another award winner.
'Peony Etched Salmon'
This Cousins/Klehm, 1981 hybrid from 1981 is a 34 inch tall double, rose type peony, salmon pink, with a mild fragrance that is 34 inches tall. Award-winning, it has a very symmetrical appearance with petals all the same height and finely cupped with a depth of color to the center.
Peony 'Buckeye Bell'
For an incredible splash of dark red try this semi-double peony. The flowers are silky and the blooms are dark red. Hybridized by Walter Mains in 1956, this anemone type peony is actually more maroon than red, with silky flowers. Two feet tall and two to three feet wide and hardy in zones 3-8, this multiple award winner award winner is a good grower and a fabulous cut flower.
Lastly, I must mention Peony 'White Cap'. I was bringing it from one house to another, so it was in a pot, and I realized just how stunning it is. Hardy in zones 3-8, with a height of 34 inches and a width of 25 inches, it is a real standout in the garden. Multiple awards, of course. It is the peony in the image at the top of this article. Raspberry, Japanese, with beautiful centers of ivory and pale pink staminodia, and a good grower.
Hybridized by Winchell in 1956, it is sought after as a garden specimen and cut flower.
If you have hesitated growing peonies, I hope that you will consider some of these choice beauties.