New Horizon Roses 2024

New Horizon Roses 2024

Suzanne M. Horn
National Editor, New Horizon Roses 2024

New Horizon Roses 2024 is now available for purchase in a few different formats from ARS and Amazon.
All proceeds from New Horizon Roses 2024 are generously donated to the American Rose Society by the
editor, Suzanne Horn.

Now in its 42nd year, the 2024 edition contains 1,601 reports by 110 reporters from 28 different states.
The reports comment on the exhibition potential of 379 roses introduced in the last five years including
hybrid teas, grandifloras, floribundas, polyanthas, minifloras, miniatures, shrubs, and climbers.

Supplementing the comments are color photographs of 320 roses. The reports are presented alphabetically
and include information on known sources for the reviewed varieties. This edition also contains a new
section on “Sneak Peeks” of new roses from some of our top hybridizers.

• A downloadable PDF is available on the ARS website at the following link: https://bit.ly/3ZKca5C

• A large glossy paperback book edition is available on Amazon for $31.37 (22% off) by typing “New
Horizon Roses 2024” into the search bar or clicking on this link: https://bit.ly/3BApJue

• A Kindle edition is also available on Amazon for $9.99 by typing “New Horizon Roses 2024” into the
search bar and then clicking on the Kindle option.

You won’t want to buy any roses this fall without consulting the findings of our trusty New Horizon
Roses national reporters.

American Rose Center Thanks Tubbs Hardware

American Rose Center Thanks Tubbs Hardware

On or about Thursday, Sept. 12, two commercial-grade lawnmowers were stolen from the American Rose Center. The missing equipment represents $20,000. It includes a Toro standing mower, an Exmark riding lawnmower and a trailer with a lift gate added to the back. This has been reported to local law enforcement and detectives continue to look for the person or people responsible for this theft.
We are so grateful to Don Tubbs of Tubbs Hardware for loaning us a lawnmower to keep our grounds tidy until we can replace this equipment.
You can view a news story here: https://bit.ly/3zGRmRU 

The Miniature Moss Rose

Over fifty years ago, in 1948, Ralph Moore began a program to breed and develop everblooming miniature moss roses. He had no idea about what he was actually letting himself in for. Fifteen years passed before he saw much in the way of real results and another 10 years after that before he would have any new miniature moss roses to sell to the public. Today, there are a number of miniature moss roses on the market, most are from Ralph Moore but some from other breeders as well. As they gain in popularity, we thought you might like to find out a little bit more about them.

Older Moss Roses

The original Moss Rose, a sport from Rosa centifolia, created quite a stir when it was first introduced in the early 1700′s. It was similar in appearance to R. centifolia except for numerous small glands on its flower buds and upper stems which create a mossy effect. The glands are scented and add to the fragrance of the flowers. If you touch the moss it feels sticky and leaves its scent on your fingers. This “moss” varies with each variety and may have its own distinctive fragrance.

Great things were predicted for Moss Roses. It is estimated that several hundred varieties were introduced, but today only a few are still grown. In size they range from dwarf varieties like Little Gem and Mousseline to tall pillar roses like Jeanne de Montfort and William Lobb, both of which are capable of reaching 8 feet.

When Little Gem was introduced in 1880, its raiser, William Paul, actually described it as a miniature Moss Rose. This, in spite of the fact that it can grow to 3 to 4 feet and has blossoms that are about 3 inches across. The bush is densely covered with small, double crimson flowers with an old-fashioned look. It was very popular with the Victorians.

 

Mousseline (also known as ‘Alfred de Dalmas’) is a continuous-blooming Moss Rose that was also very popular. The fragrant creamy-pink blossoms are semi-double with a center of deep golden stamens.

Graham Stuart Thomas tells us that Jeanne de Montfort, one of the most vigorous Moss Roses, apart from William Lobb, boasts burgundy-colored moss and frilly clear pink flowers.

William Lobb (‘Duchesse d’Istrie’, ‘Old Velvet Moss’) was introduced in 1855 and is still one of the most popular Moss Roses both because of its large size and the color of its flowers. Peter Beales describes the flowers as “a mixture of purple, grey, magenta, and pink…”

During the better part of the 18th century and up until the close of the 19th century moss roses were very popular because they were unusual, hardy, and fragrant. However, they are difficult to breed — they set few or no hips and produce little, if any, pollen.

In spite of this, several modern varieties have been bred. Nearly all are tall growing, spring flowering and not too different from the old Moss Roses. From Mr. Moore’s point of view, of these Golden Moss and Gabriel Noyelle were the most significant.

Golden Moss (Moss, Dot, 1932) resulted from a cross of Frau Karl Druschki x (Souv. de Claudius Pernet x Blanche Moreau). Ralph Moore has used this rose extensively in his breeding program. In growth habit, it is similar to its seed parent, Frau Karl Druschki, a large, white Hybrid Perpetual. Its other parent is the product of a cross between Souv. de Claudius Pernet, a yellow Hybrid Tea, and Blanche Moreau, a white Moss. Golden Moss has well-mossed buds and its flowers are a soft peach-yellow. It is once-blooming.

The parents of Gabrielle Noyelle (Moss, Buatois, 1933) are Salet, a pink Moss, and Souv. de Mme. Krueger, a salmon-orange Hybrid Tea. Gabrielle Noyelle has well mossed buds, soft salmon-pink flowers, and it is repeat-blooming.

Ralph Moore’s Early Successes

Ralph Moore’s first successful Moss rose was O.M. (“Orange Moss”). To obtain it, he crossed Mark Sullivan (Hybrid Tea, Mallerin, 1942, and which Stirling Macoboy in The Ultimate Rose Book, describes as “a lovely blend of gold all veined and shaded with scarlet”) with Golden Moss. All of the resulting seedlings were tall-growing (8 ft. to 10 ft.) once-bloomers and only one of them was really mossed. That was O.M. It has flowers that change from a bright orange to orange-pink as they mature. Although it sets few hips, it produces pollen abundantly.

In order to recover the repeat blooming characteristic, Mr. Moore had to make many more crosses with O.M. as the pollen parent and hybrid tea and floribunda varieties as the seed parent. But in doing so much of the Moss was lost.

Goldmoss (Floribunda/Moss, Moore, 1972) is Ralph Moore’s first clear yellow bush type everblooming moss rose. [Ed. Note: Modern Roses 10 lists it as a Floribunda.] Mr. Moore crossed a yellow Hybrid Tea seedling with O.M. which resulted in a number of yellow and orange-colored moss roses. Nearly all were tall growing once-bloomers. He took one of the best of these, a clear yellow, and crossed it with the floribunda Rumba (Poulsen, 1958). Goldmoss was the result.

Rougemoss (Floribunda/Moss, Moore, 1972) resulted from a cross of Rumba with an unnamed seedling itself descended from Pinocchio (Floribunda, Kordes, 1940), William Lobb, Red Ripples (Floribunda, Krause, 1942), and O.M. This cross produced a number of bush moss roses in colors ranging from medium pink to red and orange red.

 

In his 1978 monograph entitled The Breeding and Development of Modern Moss Roses, Ralph Moore said that he believed that Rougemoss and Goldmoss had within their gene pools the makings of the new moss roses of the future. Since that time, Goldmoss has figured in the parentage of a number of roses, like Apricot Twist, Playgold, and Yellow Mini-Wonder, to name a few. But most of these offspring have not displayed any mossing. One exception is Paintbrush (Miniature, Moore, 1975), the product of a cross with Fairy Moss. This rose has mossy apricot-yellow buds which open into 10-petaled daisywhite flow.

Miniature Moss Roses Today

Fairy Moss is the first of Ralph Moore’s repeat-blooming miniature moss roses. It was introduced in 1969. It had taken over two decades of work to reach this point! The buds, which are lightly mossed, and flowers of this rose are a bright medium pink and it sets seed readily. Fairy Moss has proven to be a fertile parent. In fact, it has figured in the parentage of just about every miniature moss rose on the market today.

To give you an idea of the range of the miniature moss roses, here is a sampling. All of these roses are repeat-blooming and to lesser or greater degrees show mossing.

Kara (Moore1972, aka ‘Dear One’) is the result of a cross of Fairy Moss x Fairy Moss. Mossy buds open into single (5 petals), 1-1/4″ rose-pink flowers. It makes a low, very compact plant that covers itself with tiny very mossy buds borne singly and in clusters.

Dresden Doll (Moore 1975) is one of the better known miniature moss roses — it’s offered by nurseries in Canada and Europe, as well as the United States. It has heavily mossed buds which open into double soft pink fragrant flowers that Stirling Macoboy in The Ultimate Rose Book describes as “perfect replicas of an old-fashioned, full-sized Moss Rose.”

 

Lemon Delight (Moore, 1978), like Paintbrush, is the result of a cross of Fairy Moss and Goldmoss. As you may have surmised from the name, the flowers are lemon-yellow in color, but the moss on the buds smells like lemon, too!

Strawberry Swirl (Moore 1978) has 48 red-and-white-striped petals. The blossom is similar in its striping to ‘Rosa Mundi’, but formed like a Hybrid Tea.

Double Treat (Moore 1986) has mossy buds that open into rosy-red and orange-yellow striped, almost hand-painted, blossoms — each one unique.

Scarlet Mosstm (Moore 1988) has been described as outstanding and the reddest of any moss rose. It descends from the red climber, Dortmund (Kordesii, Kordes, 1955), crossed with a miniature moss seedling and a striped miniature moss seeding.

Secret Recipe (Moore 1994), the offspring of the yellow floribunda, Little Darling, and an unnamed seedling, has 2-inch red-and-white striped blossoms.

The Miniature Moss Rose Story continues in Part II with an in-depth look at Crested Sweetheart, a climber that Mr. Moore introduced in 1988. The flower is old-fashioned in appearance with wonderful mossing ala Chapeau de Napoleon on its buds.

About Leaves!

About Leaves!

Jolene Adams

Master Rosarian, NCNH

ARS Past President

This article is a 2009 Award of Merit winner.

Roses & You, June 2020

Your roses are actively growing now and pushing out leaves – burgundy, dark green, light green, shiny – clean new leaves. The leaves are more than just lovely foliage that covers the plant and keeps the sun from burning the tender bark of the stems.

Leaves provide the surface area needed for the rose to collect sunlight and conduct photosynthesis, which produces food for the plant. Rose leaves are described as “pinnate” – that means there is a central rib and then leaflets off to each side, with one terminal leaflet. Rose leaves can have 2, 3, 5, 7, 9, 11, 13 leaflets. Most modern roses have a 5-leaflet leave with perhaps a few 3-leaflet leaves close to the bloom.

The leaves grow on alternate sides of the stem. There is a short, broad blade called the stipule at the base of the long “rib” which is the petiole. The stipule often has two long projections called auricles. Some auricles are curly, some are straight. The leaflets themselves are attached to the petiole (the “rib”) by short petiolels.

Have you noticed that roses have different shaped leaflets? Some are very oval, others are long and slender, and you can find leaflets on some roses that are just about round. The shape of the leaflets are a good identifier for some roses.

Then there are the edges of the leaflets. The edge is called the leaf margin. The margin can be smooth, slightly saw-toothed, or even very deeply saw-toothed. This is another identifier.

Leaflets have a thin, protective layer of cells on the upper and lower surface, called the epidermis. Some leaflets also have a glossy coating on top called a cuticle. This helps prevent fungus disease organisms from puncturing the skin of the leaf and getting inside. Just beneath the epidermis are thickly packed palisade cells which contain chlorophyll. On the bottom of the leaflet, the palisade cells have big gaps between them so water vapor, carbon dioxide and oxygen can move around. There are guard cells on the epidermis that can close the opening (the stomate) to these open area so nothing gets in or out.

The inside of the leaflet is a spongy mass of cells used for storage and transporting food. Running through the middle of this area are the “veins” which are vascular bundles – the same xylem and phloem that we find in the stems. These transport water and food.

Leaves are a ‘service organization’ for photosynthesis, respiration and transpiration – a veritable HMO for your rose.

PHOTOSYNTHESIS

Photosynthesis happens when the green leaves produce nutrients (carbohydrates). When there is sunlight and chlorophyll present, the leaves convert carbon dioxide (CO2) and water (H2O) into carbohydrates (C6H12O6). No Atkins diet for these guys!! These carbohydrates are simple sugars – that’s why sap tastes slightly sweet! Oxygen (O2) is left over and released into the atmosphere. Without green plants getting rid of excess oxygen – we wouldn’t have breathable air on this planet.

RESPIRATION

Once the carbohydrates are created in the leaves, they are moved around in the plant and broken up into other compounds by enzymes within the cells. This releases chemical energy which is used in many other cell processes. Water and carbon dioxide are also released. The rate of respiration depends on temperature and the availability of oxygen and the simple carbohydrates. Respiration speeds up when it is warm and slows way down when it gets cold. But – – it never stops! The plant is continually feeding off of the chemical energy created during respiration. Parts of the plant that are cut off or harvested – like a long-stemmed rose – still respire!

So – photosynthesis makes the food (the simple carbohydrates), and respiration consumes the food. This goes on in a cycle. The photosynthesis part happens in the day when there is light and it peaks during midday and ceases at night. Meanwhile, respiration occurs 24/7, at variable rates depending on temperature. In order for the bush to grow and develop normally, photosynthesis must occur at a rate that greatly exceeds the rate of respiration.

TRANSPIRATION

Water moves through the plant, going from an area of high water concentration (like the roots) to areas of low water concentration (like the leaves and stem tips). Water evaporates from the leaves through the stomata on the underside of the leaves. A continuous flowing column of water is maintained in the xylem from root to stomata, as long as there is water in the soil and the stomata are open. Transpiration helps to cool the rose bush on hot days, and transports minerals and organic compound from the roots to the leaves. It stops at night when the stomata close up.

Your rose is a living, breathing (in the sense that oxygen and carbon dioxide are exchanged during the life processes) food producing machine that relies on YOU to supply water and adequate minerals and organic compounds to the roots so its leaves can do their job of producing energy for the life processes of the plant. You are responsible – after all, your rose can’t borrow the keys and drive to the nursery to shop for nutrients!

Rose Downy Mildew Review

Found in nearly every state across the U.S., rose downy mildew has been a serious problem over the past two decades. Here are some tips on cultural practices and fungicides used to control the pathogen.

During the past 20 years, rose downy mildew has become a serious problem, causing significant losses to growers almost every year. The disease has been found in nearly every state across the United States (and Canadian provinces). It does not occur each year since conditions that promote it are not always present.

Various downy mildew diseases can occur on many plants (including roses) in the nursery or landscape, but not all of these are caused by the same pathogen. The downy mildews on most vegetables and flowers are distinct — they do not cross from one plant to another as a general rule, unless the disease hosts are from the same plant family. The cause of rose downy mildew is Peronospora sparsa, which also attacks certain cane berries (blackberry and raspberry) and all types of roses, both wild and cultivated.

Although it may seem that your bare-root roses come with downy mildew, they may be infected from other sources. Roses in landscapes or natural areas around your production site, as well as crop material left over from previous seasons, are likely sources of a downy mildew outbreak. The spores can live in these roses in a dormant state only to become active when the cool, wet weather of late winter and early spring occurs. Be sure to check last year’s roses carefully for signs of downy mildew just as often as you check those in this year’s production. If you are not checking frequently, your first indication of trouble may be extensive leaf drop!

Symptoms

Rose downy mildew is remarkably variable. In the past 20 years the most common symptom has been angular, tan spots with a very small amount of white crystalline sporulation on leaf undersides. The name of the pathogen —Peronospora sparsa — reflects the sparse production of white spores. Sometimes collapsing buds or cankers form on newly emerging rose canes. Different species and cultivars of roses respond differently to downy mildew, making a diagnosis very difficult. Severe leaf drop is common on some cultivars.

Tiny speckles may form that are tan or even bright pink. Such symptoms are difficult to distinguish from early infections with Botrytis, powdery mildew or even rust. Under moist conditions, leaves turn brownish or yellow and drop. A white, downy fungus growth may occur on leaf undersides, but this is usually too hard to see without a microscope. Under drier conditions, leaf spots appear as brown burned areas, mimicking spray injury. Reddish streaks or sunken cankers can also occur on rose canes. Since similar cankers can be caused by other pathogens like Botrytis and Coniothyrium, it is a good idea to have canker symptoms diagnosed by a university or private lab. Sometimes downy mildew sporulation can be observed directly on discolored spots on canes if they are first incubated at a high humidity for a few days.

Cultural Control

Symptoms can appear almost overnight and a severe outbreak can take off if you do not act preventively. Fans and wind easily move spores from plant to plant but are your best allies in preventing downy mildew outbreaks, since they improve air circulation around plants, dry leaves rapidly and reduce relative humidity. Downy mildew weather is cool to warm, humid and rainy. Wet leaves and high humidity will trigger sporulation overnight. When the sun comes up, leaves start to dry and spores are released. Most spores spread by fans or wind and infect new leaves before noon. Six hours of constant leaf wetness are enough for spores of many downy mildew fungi to germinate and infect leaves. Even though fans might move spores, you should use them along with venting to reduce humidity and leaf wetness. Try to water early in the day or whenever leaves will dry quickly, to ensure dry foliage at night. Check all new plants for symptoms upon receipt. Early detection is the only way to control downy mildew. Scout all plants at least once a week, preferably every two to three days. Remember: hungry plants are more susceptible to downy mildew. Maintain a balanced fertility program to protect your crops.

The cultural steps that should be taken when growing garden roses are:

  1. Destroy rose debris from previous crops — spores can overwinter in leaves and canes, then the downy mildew can attack new plants.

  2. To protect them from infection, isolate new shipments away from last year’s plants.

  3. Space plants to allow rapid drying of leaves. If the leaves are touching, they are too close. As the canopy closes in, the humidity increases.

  4. Water at a time of day that will promote the fastest possible drying.

  5. Apply fungicides preventively.

Fungicides for Control

Choosing the most effective fungicides to prevent or eradicate rose downy mildew can be tough. Although plant pathologists usually like to lump a lot of trials on a single type of pathogen together, we sometimes find that specific results occur on specific crops. This has been the case with rose in our experience. Start early with a rotation of chemicals for prevention.

Chase Horticultural Research, Inc. performed a trial on greenhouse potted roses in 2004. The roses were infected prior to spraying twice on a 10-day interval. Results showed that in an eradication scenario, the strobilurins were not effective on rose downy mildew. Heritage and Insignia were not effective used at very low rates. Cygnus (no longer available) and Compass O were more effective (also used at very low rates) but were still not significantly better than the water-sprayed controls. This is not an unusual result for rose downy mildew based on reviewing all of the trials that have been published or otherwise made available. Using even the highest labeled rates of the strobilurins is rarely as effective on roses as it is on nearly all other plants affected by downy mildew fungi.

In the same trial, excellent control was seen with Segway (all rates tested), Stature DM,

Aliette and Subdue MAXX (used as a foliar spray in this case). Be sure to tank-mix Subdue MAXX with another product for downy mildew control if you are going to spray the product (as per label directions). Remember that the 0 REI is for drenching Subdue MAXX and use as a foliar spray for downy mildew requires a 48 hour REI.

Do not use more than 2 oz/100 gal of Aliette, as higher rates have been shown to reduce downy mildew control on some plants.

Over the past 15 years about 15 trials have been performed from Florida to Alabama to California in the greenhouse and in the field.

The most consistently effective products for downy mildew on roses have been Subdue MAXX (1 to 2 oz/100 gal) used as a foliar spray, Micora (8 oz/100 gal), Stature SC (12.25 oz/100 gal), Aliette (2.5 oz/100 gal) and Segway (3.5oz/100 gal). Remember to follow labels carefully. Subdue MAXX and Adorn must be tank-mixed with another product from a different MOA group that is effective on downy mildew (they can be mixed with each other, for example). You cannot rotate products with the same MOA group number. That means products in MOA group 40(Stature, Micora and Orvego), although really effective, cannot be rotated with one another. Similarly, if you decide to use a strobilurin (or Fen-Stop), these materials all belong to MOA 11 and rotation dictates using something from another MOA group.

Another fact that appeared in reviewing the available trials was that a shorter interval is usually more effective. Thus, using a fungicide once a week is better than using one once a month. Using one every 10 days is better than every 14 days. However, for a spray program to be effective you must remember to apply it. If a 10-day interval is hard to implement, you should switch to every seven days (curative) or 14 days (preventative). Weekly spraying to prevent downy mildew on sensitive crops is common at times of year when environmental conditions favor disease. Spraying more often may be counterproductive.

A final word — make sure you are treating the right disease. It is surprising how many times roses are being sprayed for black spot when they really have downy mildew. Get a diagnosis!

A.R. Chase is plant pathologist at Chase Agricultural Consulting LLC and can be reached at archase@chaseresearch.net. Margery L. Daughtrey is senior extension associate at Cornell University’s Long Island Horticultural Research & Extension Center and can be reached at mld9@cornell.edu.

“This article originally appeared in the May 2013 issue of GPN magazine. Copyright Scranton Gillette Communications.” Re-printed with special permission from GPN Greenhouse Product News Magazine, Scranton Gillette Communications, May 2013.

American Rose Society