Shrub · Rosaceae
Grandiflora Rose
Rosa
Tall, long-stemmed, and built 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
The grandiflora is one of the taller modern roses, bred in 1954 by crossing a hybrid tea with a floribunda. From that pairing it took the shapely, high-centered flower of the hybrid tea and the tall, clustered habit of the floribunda, so a single plant can hand you cutting-quality blooms one to a stem or in full sprays. Queen Elizabeth started the whole class and still anchors most gardens.
These are sun-loving shrubs that reach 4 to 6 feet and keep flowering from May right up to frost. They ask for a fair bit of attention, mostly steady water at the roots and a hard pruning each late winter, and they reward it with months of color. Give them room and airflow and they stay far healthier.
The thorns are the one thing to respect. Grandifloras carry sharp prickles along every cane, so gloves and long sleeves earn their keep at pruning time. The plant itself is safe around pets and people, with no toxin to worry about.
Care
The short version: full sun and at least six hours of it, slightly acidic, well-drained soil rich in compost, deep morning watering at the base, a monthly feed through the growing season, and a hard cutback in late winter.
Light
Grandifloras want full sun, six hours or more of it a day, to bloom their best. They will take a little partial shade, but less light means fewer flowers and more disease as the leaves stay damp longer.
Water
Water deeply and on a regular schedule, ideally in the morning so the leaves dry by evening. Soak the root zone rather than splashing the foliage, since wet leaves are how black spot and mildew get started. Aim for even, medium moisture every 4 to 7 days.
Soil
Plant in well-drained loam, slightly acidic and rich in organic matter. A pH of 6.0 to 6.5 suits them, so dig in plenty of compost before planting and they will root deep and grow strong.
Temperature
Grandifloras are tough, taking conditions from -20°F to 95°F (-29°C to 35°C) across their hardy range. They handle real cold once established, though extreme summer heat can stress the blooms.
Humidity
Ordinary outdoor humidity is fine, so there's no number to chase here. Airflow matters far more, because still, damp air around crowded canes is exactly what the fungal diseases need.
Feeding
Feed monthly through spring and summer with a balanced rose fertilizer while the plant is actively growing. Ease back as the season winds down, and go light on nitrogen, which pushes the soft growth that aphids and mildew prefer.
Pruning
Prune hard in late winter to early spring, cutting the canes back to roughly 12 to 18 inches from the ground. Take out anything dead, weak, or crossing, then deadhead spent blooms through the season to keep new flowers coming.
Repotting
Grandifloras are grown in the ground, not pots, so repotting rarely comes up. If you do keep one in a container, move it up a size when roots circle the pot or push through the drainage holes and bloom starts to fade.
Size & spacing
Expect 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 room that air moves freely between the canes, which is your best defense against leaf disease.
When to plant
Grandifloras run on the seasons. Set new plants out in early spring once hard frost has passed, or in fall where winters stay mild, then look for the first flush of bloom in May and a steady run of flowers until frost shuts the show 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
Nearly every rose problem starts on the leaves and the soft new growth, and most of it traces back to wet foliage or crowding. Catch the early signs and a quick response keeps a small issue from spreading. Match what you see below, then act while it still does some good.
Black spots with yellow halos spreading up from the lower leaves
This is black spot, the fungus that troubles roses more than any other and shows up first on the older, inner leaves. It takes hold when foliage stays wet, so water at the base in the morning, strip off the marked leaves, and rake up any that fall. Open the plant up with pruning and a fungicide so air and light reach every cane.
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
White powdery film on new growth and curling young leaves
That dusty white coating is powdery mildew, and it settles in when days are warm but nights turn cool and humid. Cut out the worst of the infected shoots, give the plant more sun and breathing room, and ease off the nitrogen that pushes soft, vulnerable growth. A labeled fungicide or horticultural oil clears up a stubborn case.
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
Soft green or black insects crowding the buds with sticky residue
Those clustered, soft-bodied bugs on the tender shoots are aphids, and the sticky honeydew they leave behind can turn black with sooty mold. Knock them off with a hard spray of water, then follow up with insecticidal soap or horticultural oil where they linger. Lady beetles and lacewings will do much of the work if you let them, so go light on the nitrogen that feeds the soft growth aphids love.
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 on this one: true roses are non-toxic to pets and people alike, so a curious nibble from a cat, dog, or rabbit won't cause poisoning. The petals and hips are even edible. The only real hazard is mechanical, the sharp thorns along the canes, so handle the plant with care.
Safe for
People · Cats · Dogs · Horses · Rabbits · Livestock · Birds
Cats None
The ASPCA lists true roses as non-toxic to cats, so a nibbled leaf or petal won't poison one. The real worry is the thorns, which can scratch a curious paw or mouth.
Dogs None
Roses are safe for dogs to be around, and chewing on the foliage causes no poisoning. Watch instead for thorn scratches on the nose or paws.
Horses None
The ASPCA lists roses as non-toxic to horses. A grazing horse can browse the leaves without harm, though the prickly canes may catch on the lips.
Rabbits None
Rabbits can eat rose leaves and petals safely, and many gardeners feed them as a treat. Strip the thorns from any cuttings you hand over.
Livestock None
Goats, sheep, and cattle browse rose foliage with no risk of poisoning. The only drawback is the sharp prickles along the canes.
Birds None
Roses pose no chemical danger to birds, and the hips are a welcome winter food for many wild species.
People None
Rose petals and hips are edible and turn up in teas, jams, and syrups. The thorns are the one hazard, so wear 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 turn up in most gardens, and these are the ones worth knowing by name.
Queen Elizabeth
The first grandiflora ever introduced, this upright plant stands 4 to 6 feet tall and carries double silver-pink blooms both singly and in long-stemmed clusters.
Gold Medal
A tall grandiflora prized for its golden-yellow, hybrid-tea-shaped flowers held on long cutting stems.
Tournament of Roses
A vigorous, disease-tolerant grandiflora that opens coral-pink double blooms in generous 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
Roses can be multiplied a few different ways, though some take far more skill than others. Here is how each method works and what to expect.
GraftingDemanding
Late summer for budding onto rootstock · One growing season
This is how nurseries make named grandifloras true to type, budding a scion onto a hardier, disease-resistant wild rose rootstock in late summer. The new plant settles in over a single growing season. It takes a steady hand, so most home gardeners leave it to the pros.
Stem cuttingsModerate
Late spring through summer from semi-hardwood growth · Several weeks to a few months to root
Take cuttings from healthy, current-season stems anytime from late spring through summer, once the growth has firmed into semi-hardwood. Rooting runs anywhere from a few weeks to a few months, and how well it takes depends a lot on the cultivar. Keep in mind that 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 supple in spring or summer, bend a low one down and bury a section in the soil. Roots form over the course of a season where the buried wood meets moist ground, and you can then sever the new plant and move it.
Myths
Roses are poisonous to cats and dogs.
The ASPCA lists true roses in the genus Rosa as non-toxic to cats, dogs, and horses, so a chewed leaf or petal won't poison a pet. The only real danger is a scratch from the thorns. Watch out for unrelated plants that borrow the name, like desert rose or Lenten rose, since those can be toxic.
Grandiflora is a botanical species of rose.
Grandiflora is a garden class, not a species. Breeders created it in 1954 by crossing hybrid teas with floribundas, pairing the shapely hybrid-tea bloom with the tall, clustered habit of a floribunda.