How to Plant, Grow, and Care for Grandiflora Roses

Roses have a reputation for being a bit complicated. And rightfully so. They are not the easiest plants to grow, nor are they low maintenance. However, the payoff for putting in the effort is definitely worthwhile. There are many types of roses, and each is more beautiful than the last.

Let’s discuss the wonderful grandiflora rose and how to care for this bloom-producing wonder of a plant. 

What are Grandiflora Roses?

Grandiflora roses are a florist’s dream. These long-stemmed hybrid roses come from breeding floribunda roses with hybrid teas. They have the incredible repeat blooming power of their floribunda parents. From their hybrid tea parents, they inherit a wide range of colors and long, slender stems perfect for cut arrangements. 

These roses have a beautiful tea rose form, but they bloom in clusters repeatedly throughout the season. They are large shrubs. They are very popular with florists for both their stems and their delightful flowers. 

History

Grandiflora roses are hybrid roses that were first introduced in the 1950s, so they are a relatively new species. The first recognized variety, ‘Queen Elizabeth,’ came into the trade in 1954 or 1955, named for the young queen of Great Britain. This remains the most famous and award-winning grandiflora. It was developed by Dr. Walter Lammerts, and is the product of parent roses ‘Charlotte Armstrong’ x ‘Floradora’.

The name means large flower and is fitting, as this is the quality that is most distinctive about the species. These days, grandiflora roses are very popular and well-known in floristry and gardening. Their blooms are less fragrant than old garden roses, but they are just as stunning.

Native Area

Grandiflora roses are hybrids, so they do not have a natural native range. Roses are thought to have originated in ancient Central Asia. The roses of today bear only a moderate resemblance to these ancestors. The first rose of this type was introduced by Germain Seed & Plant Company in Los Angeles, California. 

Characteristics

As implied by their name, grandifloras are well known for their large and showy flowers. They present with the long, strong stems of their hybrid tea parentage. Unlike hybrid teas, they also have the blooming habit of their floribunda parents. They bloom repeatedly over the growing season. This makes them desirable in the floristry trade. 

These flowering perennials are tall, with some varieties reaching up to eight feet tall. They have an upright growth habit and grow quite full, making them excellent garden plants. 

Grandiflora flowers are large and come in a wide variety of vivid colors. They range from white to deep red and every color in between, including some bi-color varieties. The flowers can be single or bloom in clusters like floribundas. They tend to have the high-centered form of hybrid teas. 

Uses

Like most roses, the function and use of these plants are most commonly ornamental. They make an excellent addition to the cutting garden, as their flowers are ideal for floral arranging. They are the most common rose grown in the floristry trade. 

Because of their height and fullness, they make great specimen plants and focal points. Use them as middle or background plants in the flower garden. Here, they will serve as a stunning backdrop for other flowering plants. 

Roses, in general, commonly have a place in essential oil production. Grandiflora roses are not commonly used for this purpose, however. 

Where to Buy Grandiflora Roses

 These plants are somewhat less popular for gardening than floribundas or hybrid teas. They are not difficult to find though, and are seasonally available at most nurseries. It’s unlikely that you will encounter difficulty finding a grandiflora rose locally. However, many online retailers carry these plants. A wide array of varieties is available online and in catalogs.

Planting

Plant your roses in the spring or fall when temperatures range between 40-60 degrees Fahrenheit. In the fall, make sure they’ll have at least six weeks to establish prior to the first frost. In spring, wait until freezing temperatures have passed.

Most roses are quite cold-hardy. Pampering your young roses is a good idea, though, as it will help them to get established sooner. Depending on your climate, this period should fall somewhere between February and May. Planting in the spring will help your rose to establish roots before the heat of summer sets in. 

Choose a location with full sun and loose, fertile soil. For bare-root roses, plant as soon as possible. Allowing a bare-root rose to lie around too long can kill the plant.  If you must wait, store your bare root rose in a cool, dark location such as a garage or basement. 

Don’t allow your roots to dry out in the meantime. Wrap the roots in plastic so they stay moist. They should stay between 32°-42° F until you can plant them. If you can’t plant your bare root rose for a long period, temporarily plant it in a container.

Dig a hole large enough to spread the roots out. Grandifloras typically have grafted rootstock. This should be a consideration when planting them. In cooler climates, plant your rose so that the grafted union is two to three inches below the surface. In warmer climates, one to two inches is sufficient. This will prevent the rootstock roses from producing suckers. 

Rehydrate your roses roots by soaking them in water for about 2 hours before planting. In the center of the hole, form a mound of soil or compost and spread the roots over the mound. Make sure to give them ample space. Backfill the hole with a mixture of soil and compost or manure to give your rose a healthy start. 

For potted roses, similar rules apply. Water your rose thoroughly a few hours before planting. Give the plant enough time to absorb the water. Dig a hole that is as deep and twice as wide as the root ball and situate your rose similarly to a bare root rose. The graft joint should lie below the surface by one to three inches, depending on your climate. 

When you backfill the hole, water the soil well when it is about 90% filled. This will help settle the soil. Then, fill the remainder of the hole and water your rose in. Always water your roses deeply to encourage deep root growth. 

How to Grow

Grandifloras are generally hardy plants with a vigorous growth rate.  Caring for them is similar to the way you would care for other types of roses. They prefer rich soil, and they need a substantial amount of nutrients. They have excellent disease resistance and are typically easier to care for than most roses. 

Light

These roses are sun-loving plants that can tolerate a substantial amount of exposure and heat. Plant your roses in a spot that gets full sun. This means that they should receive at least six, preferably eight hours of sun daily. More sun will equate to more flowers for these roses. Less sun will lead to leggy growth and an overall less attractive plant.

Water

Grandiflora roses like plenty of water. If you live in a climate that receives several inches of rain weekly, you may be able to avoid supplemental watering. Otherwise, you’ll want to water your rose once or twice per week, depending on rainfall. 

Most rose gardeners abide by the theory that you should water more deeply and not more often. This means that you are better off watering less frequently but giving your rose more water at each watering. 

Don’t gloss over these plants when you water, but take some time and soak the ground around the base of the plant. Watering deeply will send the roots deeper, and healthy roots make a healthy plant.

Soil

In terms of pH, roses prefer soil that has a neutral pH or one that veers just slightly acidic. Somewhere in the ballpark of 6.5-7.0 is perfect. The acidity of the soil directly influences how available certain nutrients are for the plant. 

The ideal soil type for roses is loamy, fertile, and loose. Roses will grow in just about any soil type. But, amending it to create a nutrient-rich soil that doesn’t compact easily will help keep your roots healthiest. Add plenty of decayed organic matter, like compost or worm castings to your soil ahead of planting. 

Temperature and Humidity

These plants do not mind heat or humidity. While the ideal temperature for grandiflora roses is around 70° F, they can tolerate more heat. When the temperature rises consistently over 85° F, you are likely to see a drop in flower production. Heat stress decreases flowering. 

Many grandifloras are hardy to Zone 4. Their roots will withstand temperatures as low as 10° F. It is best to give your roses some protection in the winter. A heavy layer of mulch will go a long way toward insulating the roots. 

Grandiflora roses tolerate humidity well. A level of 60-70% is ideal, but they like moisture, so a slightly higher amount won’t harm these plants.  

Fertilizing

Roses are heavy feeders. If you want strong, vigorous plants that do their best blooming, you will want to fertilize your plants. At a minimum, you should fertilize your grandifloras two to three times per year. I say at a minimum because they can handle fertilizing every four to five weeks during the growing season. 

Your first yearly application of fertilizer should take place as soon as leaves begin to appear. This will be in early to mid-spring, depending on your climate. This application should be a high-nitrogen fertilizer to encourage green growth. Alfalfa meal makes a good top dressing at this time. 

Throughout the growing season, you can fertilize once per month. If you are using an organic liquid fertilizer, you can bump the application to every two weeks. A slow-release formula will last longer, so you can apply it less frequently. As the summer wears on, use a formula with less nitrogen to encourage strong roots without a lot of green growth.

Stop fertilizing about eight weeks before your first expected frost. You don’t want your rose to produce a lot of growth leading up to winter, as this makes the plant more vulnerable to the cold. New growth is weaker and more susceptible to frost damage. 

Maintenance

When it comes to maintaining your rose, the main facets are pruning and preparing for winter. To prep for cold weather, prune your canes back to about three feet tall. Remove any leaves, and tie the canes together with a synthetic material that won’t fall apart in the winter weather. 

Covering the ground around your plant will help to protect the roots from cold. A layer of pine needles or mulch can help to acidify the soil a bit. Over that, spread a heavy layer of mulch. You should do this before the ground freezes to maintain the heat in the soil.

In late winter or early spring, before leaves emerge, you can do another round of trimming. Remove any dead or damaged branches first. Trim off any crossing branches to allow for air circulation and a more aesthetically pleasing appearance. Trim canes back to the first outward-facing bud. This will make for branching outward, away from the center of the plant. 

Make your cuts at a 45° angle, and feel free to apply a sealant to the cuts. A pruning sealer will help to prevent disease and make the plant heal faster. Think of this like a band-aid for your plant. 

Growing in Containers

You can grow roses in containers as long as the conditions are right. A grandiflora rose is a large plant, that needs a large container. Choose a container that has at least a 15-gallon capacity. Anything smaller will result in the need to re-pot frequently. Choose a pot that your rose can grow into. 

Plant your rose in a container in the same way that you would in the ground. Use a high-nutrient potting mix, and plant the rose so that the grafting joint sits below the soil. Roses in containers will not be as impervious to freezing as those in the ground. 

Plants in the ground have more soil to insulate them from the cold. A potted rose will need additional insulation from the cold. You can bring your rose indoors for the winter as well. 

Propagation

You can propagate roses by cuttings. However, grandiflora roses usually are grafted to hardy rootstock. You can propagate by grafting yourself, but it’s a more complicated process. Propagation by cuttings will result in a rose plant with a different type of root system from the parent plant. 

Take cuttings from new growth that has several sets of leaves. Your cuttings should be about six to eight inches long. Immediately place your cuttings in water to prevent the cuts from healing over. Remove the leaves from the lower half of the cutting and dip the end in a rooting hormone. Rooting hormone is optional but will result in more successful and faster rooting. 

Plant your cuttings in a moist potting mix with at least two nodes below the level of the soil. Cover your cuttings with plastic or an upside-down glass jar to create a greenhouse effect. Make sure to keep your cuttings moist while you wait for them to take root. 

Popular Varieties

Dick Clark

	botanical name Rosa ‘Dick Clark’
	sun requirements Full sun
	height 5’-6’
	hardiness zones 4-10

‘Dick Clark’ is a stunning cultivar with pinkish-red blooms that have a pale yellow center. The large blooms appear as single flowers on tall, slender stems that are ideal for cut flower arrangements. The edges of the flowers are dark and dusky in bud, but open to reveal a very bright flower. The blooms are lightly fragrant and positively radiant. 

Pop Art

	botanical name Rosa ‘WEKgoagroro’ ‘Pop Art’
	sun requirements Full sun
	height 5’
	hardiness zones 5-10

‘Pop Art’ is a warm weather-loving variety with splashy, flashy pink and yellow flowers. This plant has great disease resistance, and very full, lush blooms. The flowers are pink with light yellow streaks and grow one to a stem. They do a great job of retaining their color and have a light, fruity fragrance. 

Gold Medal

	botanical name Rosa grandiflora ‘Gold Medal’ aka ‘AROyqueli’
	sun requirements Full sun
	height 6’
	hardiness zones 4-10

These roses live up to their award-winner moniker. With deeply golden flowers that appear in clusters atop tall stems with low-profile thorns, this is a wonderful cut flower. The golden petals are deeper in color when grown in warmer climates and have a strong, fruity fragrance. 

Uptown Girl

	botanical name Rosa cv ‘WEKabacima’ ‘Uptown Girl’
	sun requirements Full sun
	height 4’
	hardiness zones 4-10

If you want the look of an old garden rose with the hardiness of a grandiflora, ‘Uptown Girl’ is a great place to start. Clusters of coral-pink flowers with tons of petals grow on this medium-sized shrub. These blooms retain their color well, and it is a gorgeous shade with lots of variation. This variety has excellent disease resistance and a light, sweet scent.

Common Problems

As beautiful as roses are, they can also be a bit high maintenance. But hey, many beautiful things are, right? Roses tend to be susceptible to a handful of pests and diseases and can be finicky about their environment. Here are some of the issues you may encounter with your grandifloras and how to deal with them. 

Not Flowering

Most roses bloom in their first year. It won’t be a full and robust bloom in most cases. Nonetheless, there ought to be flowers. If your rose goes for an entire season without blooming, there might be an issue to address. 

The first thing to consider is sunlight. Roses need substantial sunlight, and when they don’t get it, they don’t bloom. Make sure to plant your rose in a spot that receives at least six hours of sun daily. Eight hours would be better. 

The other potential culprit behind a lack of flowering is a lack of nutrients. Roses are heavy feeders, and they require a great deal of nutrients to do their best blooming. If you haven’t been fertilizing your roses, give them a good dose of fertilizer. This should kick your roses into gear and hopefully, you will see some blooms in the current or following season. 

Pests

Roses produce tasty flowers. In fact, roses are sometimes used in baking and the preparation of jams and teas. They are sweet and aromatic flowers, and they are completely edible. There are a wide variety of garden pests that will actively seek out your roses and can do a lot of damage. 

Natural insect control is best. Attracting beneficial insects such as ladybugs and lacewings, will help to control pest populations. These insects are predatory and love to feast on aphids in particular. In the absence of beneficial insects, neem oil works well to eradicate many garden pests. Just be certain to spray in the late afternoon so that it dries before the pollinators return in the morning. 

Diseases

Roses are also susceptible to a number of plant diseases. Most commonly, they tend to fall prey to types of mildew. This risk increases in humid climates or in times of excessive rainfall. To prevent mildew and fungal disease, make sure to prune properly to keep air flowing through your plant’s foliage. Keeping your plant strong by providing adequate nutrients is helpful, as well. 

A strong plant will stand up better to diseases, but sometimes things creep into the garden and make a mess of your plants. Be careful about purchasing plants from reputable sources and inspecting new plants before introducing them. 

Frequently Asked Questions