Shrub · Rosaceae
Grandiflora Rose
Rosa
Tall, long-stemmed, and happy to bloom from spring to frost, the grandiflora gives you hybrid-tea flowers on a floribunda frame.
Full sun
Every 4–7 days
USDA 5–9
4–6 ft · 1.2–1.8 m
Overview
So what exactly is a grandiflora? It's one of the taller modern roses, and breeders came up with it in 1954 by crossing a hybrid tea with a floribunda. From that pairing it picked up the shapely, high-centered flower of the hybrid tea plus the tall, clustered habit of the floribunda, which means a single plant can hand you cutting-quality blooms either one to a stem or in big sprays. Queen Elizabeth got the whole class started, and it's still a fixture in most gardens.
These are sun-loving shrubs that reach 4 to 6 feet and just keep flowering from May all the way to frost. They do ask for a bit of attention, mostly steady water at the roots and one hard pruning every late winter, but you get months of color out of the deal. Give them some room and good airflow and they'll stay a lot healthier, too.
The thorns are the one thing to take seriously. Grandifloras have sharp prickles running along every cane, so gloves and long sleeves really earn their keep come pruning time. Otherwise the plant is safe around pets and people, with no toxin to worry about, so you can grow it without a second thought.
Care
The short version: full sun and at least six hours of it, slightly acidic soil that drains well and has plenty of compost, a deep morning drink right at the base, a monthly feed through the growing season, and one good hard cutback in late winter.
Light
Give a grandiflora full sun, six hours or more a day, and it'll bloom like crazy. It'll put up with a bit of partial shade, sure, but less light means fewer flowers and more disease, since the leaves just stay damp longer.
Water
Water it deeply and on a regular schedule, ideally in the morning so the leaves have all day to dry off. Soak the root zone instead of splashing the foliage, because wet leaves are how black spot and mildew get their start. Shoot for even, medium moisture every 4 to 7 days.
Soil
Plant it in well-drained loam that's slightly acidic and rich in organic matter. A pH of 6.0 to 6.5 is what they like, so mix in plenty of compost before you plant and they'll root deep and grow strong.
Temperature
Grandifloras are tougher than you'd think, handling anything from -20°F to 95°F (-29°C to 35°C) across their range. They shrug off real cold once they're established, though a serious summer heat wave can wear the blooms out.
Humidity
Regular outdoor humidity is all they need, so there's no number to chase down. Airflow is what really matters, because still, damp air around crowded canes is exactly what the fungal diseases are looking for.
Feeding
Feed monthly through spring and summer with a balanced rose fertilizer while it's actively growing. Ease off as the season winds down, and go light on the nitrogen, since that's what pushes the soft growth aphids and mildew love.
Pruning
Prune hard in late winter to early spring, cutting the canes back to about 12 to 18 inches from the ground. Clear out anything dead, weak, or crossing, and then deadhead the spent blooms all season to keep fresh flowers coming.
Repotting
Grandifloras live in the ground, not pots, so repotting doesn't come up much. But if you've got one in a container, bump it up a size when the roots start circling or poking out the drainage holes and the blooms fall off.
Size & spacing
Figure on a plant 4 to 6 feet (122 to 183 cm) tall and 2 to 3 feet (61 to 91 cm) wide. Give each one enough space for air to move freely between the canes, since that's honestly your best defense against leaf disease.
When to plant
Grandifloras go by the seasons, so timing is easy enough. Get new plants in the ground in early spring once the hard frost is done, or in fall if your winters stay mild, and then keep an eye out for that first flush of bloom in May and a steady run of flowers right up until frost shuts things down.
Northern hemisphere
Southern hemisphere
Typical months for a temperate climate: start earlier in warm zones, later where spring frosts linger.
- Plant: early spring after the threat of hard frost, or fall in mild climates
- Harvest: May to frost
Hardiness
USDA hardiness zones: 5–9
Temperature: down to -29°C
Troubleshooting
Just about every rose problem shows up on the leaves and the soft new growth, and most of it comes back to wet foliage or crowding. Catch it early and a quick response keeps a small thing from turning into a big one. Find whatever matches below, and then step in while it still does some good.
Dark spots working their way up from the bottom leaves
So those dark spots are black spot, the rose fungus you'll run into more than any other, and it likes to begin down low on the older inner leaves. What lets it in? Wet foliage. So water at the base in the morning, pull off the leaves that are already marked, and rake up whatever drops. Then open the plant up with a little pruning, and add a fungicide if it's really pushing hard.
Fix:
- Remove and dispose of infected leaves and fallen debris
- Water at the base in the morning and keep foliage dry
- Improve air circulation by proper spacing and pruning
- Apply a labeled fungicide preventively if disease pressure is high
A dusty white coating on new growth, with young leaves curling
That dusty white film is powdery mildew, and it tends to turn up when the days are warm but the nights get cool and humid. First thing, snip out the shoots that are hit worst. Then give the plant more sun and a bit more elbow room, and ease up on the nitrogen, since all that soft growth is exactly what the mildew wants. If it's really dug in, a labeled fungicide or horticultural oil will sort it out.
Fix:
- Prune out heavily infected shoots
- Improve air circulation and sun exposure
- Avoid excess nitrogen that pushes soft growth
- Apply a labeled fungicide or horticultural oil when needed
Little soft bugs bunched on the buds, leaving a sticky mess
Those little soft bugs crowding the tender shoots? Those are aphids, and the sticky honeydew they leave behind can go black with sooty mold. A good hard spray of water knocks most of them right off, and insecticidal soap or horticultural oil handles the ones that stick around. Honestly, lady beetles and lacewings will do a lot of the work for you, so keep the nitrogen down and let them move in.
Fix:
- Dislodge aphids with a strong spray of water
- Apply insecticidal soap or horticultural oil to affected growth
- Encourage natural predators such as lady beetles and lacewings
Toxicity
Good news here: true roses aren't toxic to pets or people, so a curious nibble from a cat, dog, or rabbit isn't going to cause poisoning. The petals and hips are even edible. The only real hazard is mechanical, meaning those sharp thorns along the canes, so just handle the plant with a bit of care.
Safe for
People · Cats · Dogs · Horses · Rabbits · Livestock · Birds
Cats None
Good news for cat owners: the ASPCA calls true roses non-toxic, so a nibbled leaf or petal isn't going to poison anyone. The thorns are what you'll want to keep an eye on, since a sharp one can scratch a curious paw or mouth.
Dogs None
Dogs are just fine around a rose, and a mouthful of leaves won't do any harm. What's worth watching? Thorn scratches on the nose or paws.
Horses None
Horses are covered too, since the ASPCA lists roses as non-toxic to them. A horse can graze the leaves with no trouble, though those prickly canes might catch on the lips.
Rabbits None
Rabbits can happily eat rose leaves and petals, and plenty of folks hand them over as a treat. Just pull the thorns off any cuttings first.
Livestock None
Goats, sheep, and cattle can all browse rose foliage without any risk of poisoning. The one catch is those sharp prickles running down the canes.
Birds None
Birds have nothing to worry about with roses, and the hips actually make a nice bit of winter food for a lot of wild species.
People None
Rose petals and hips are edible, and they show up in teas, jams, and syrups all the time. The thorns are the only real catch, so throw on some gloves when you prune.
Most grandiflora roses bear sharp thorns (prickles) on the canes that can cause scratches and puncture wounds; the hazard is mechanical, not chemical. Wear gloves and long sleeves when pruning or handling.
Varieties
Only a handful of grandifloras really show up in most gardens, and these are the ones worth knowing by name.
Queen Elizabeth
This was the very first grandiflora, an upright grower that hits 4 to 6 feet and shows off double silver-pink blooms both one to a stem and in long-stemmed clusters.
Gold Medal
A tall grandiflora that folks love for its golden-yellow, hybrid-tea-shaped flowers riding on long stems that are perfect for cutting.
Tournament of Roses
A tough, vigorous grandiflora that shrugs off disease and opens coral-pink double blooms in nice full clusters.
Companions
Grandifloras do best beside aromatic plants that confuse pests and share their love of sun and good drainage, and worst anywhere near a black walnut.
Plant near
garlic: Aromatic alliums interplanted near roses are a traditional companion thought to help deter aphids.
lavender: Drought-tolerant, sun-loving companion that shares full-sun, well-drained conditions and attracts pollinators without crowding roots.
Keep apart
black walnut: Black walnut releases juglone, which can harm many garden plants; keep roses away from its root zone.
How to propagate
There are a few ways to make more roses, though some take a lot more skill than others. Here's how each one works and what you can expect.
GraftingDemanding
Late summer for budding onto rootstock · One growing season
This is how nurseries keep named grandifloras true to type. They bud a scion onto a hardier, disease-resistant wild rose rootstock in late summer, and the new plant gets going over a single growing season. It takes a pretty steady hand, though, so most home gardeners are happy to leave this one to the experts.
Stem cuttingsModerate
Late spring through summer from semi-hardwood growth · Several weeks to a few months to root
Want to try it yourself? Take cuttings from healthy, current-season stems anytime from late spring through summer, once the growth has firmed up into semi-hardwood. Rooting can take anywhere from a few weeks to a few months, and how well it goes really depends on the cultivar. And don't forget, patented varieties can't be legally propagated.
LayeringModerate
Spring to summer while canes are flexible · One season for roots to form
While the canes are still bendy in spring or summer, just pull a low one down and bury a chunk of it in the soil. Roots form over a season where that buried wood sits against moist ground, and once they do, you can cut the new plant free and move it wherever you'd like.
Myths
Roses are poisonous to cats and dogs.
Here's the thing: the ASPCA lists true roses in the genus Rosa as non-toxic to cats, dogs, and horses, so a chewed leaf or petal isn't going to poison a pet. The only real danger is a scratch from the thorns. Just watch out for other plants that borrow the rose name, like desert rose or Lenten rose, because those actually can be toxic.
Grandiflora is a botanical species of rose.
Nope, grandiflora is a garden class, not a species. Breeders came up with it back in 1954 by crossing hybrid teas with floribundas, so you get the pretty hybrid-tea bloom on the tall, clustered frame of a floribunda.