Winter is the easy part of growing roses in Louisiana. Summer heat, humidity and blackspot decide which roses last. Knock Out, New Dawn and the old China and Tea roses shrug off the climate, and the very cold-hardy rugosas live here but sulk in the worst heat. Many roses on local shelves were bred for places with real winters and cooler, drier summers. This is how to sort them before you spend money. For the basics of getting a bed started, see growing roses in Louisiana.
Which roses survive a Louisiana winter
Louisiana runs from USDA hardiness zones 8a to 10a on the USDA Plant Hardiness Zone Map. That system is built on one number, the average annual extreme minimum temperature, so it says how cold a spot gets on its worst nights and nothing about summer. North Louisiana sits at the cold end of the range, and the Gulf coast sits at the warm end. Nearly every rose sold in the country is hardy enough for that range.
Which types clear the cold easily?
Rugosas and the Explorer series are among the toughest roses sold anywhere. They come through winters far colder than anything Louisiana produces, so cold is never their problem here. Shrub roses, old garden roses, China roses, Tea roses and most climbers also pass without help. Hybrid teas, floribundas and grandifloras are the types that need protection in much colder country, with mounded soil and wrapped canes. Here they need little more than mulch and a cover on the odd hard night. That is less work than a gardener in the Upper Midwest puts in.
How often does Louisiana actually freeze?
Less often than most people expect. At the New Orleans reference station, a 32°F freeze happens in about 86.8 percent of years. Roughly one year in eight has no freeze at all. In the 30 to 70 percent probability band, the last spring freeze falls between January 18 and February 8, and the first fall freeze falls between December 17 and January 8. The fall window straddles the New Year, so a mild winter can pass without the plants ever going fully dormant. North Louisiana freezes far more reliably than the coast.
The real winter risk is a hard freeze after buds have swelled in a warm January. It burns new growth, and you prune the damaged canes back to green, healthy wood. Mulch and cover advice for those nights is in Protecting Roses Through a Louisiana Winter.
Since almost everything survives the cold, hardiness is a weak way to choose a rose here. Heat tolerance and leaf health through a long, wet summer are what separate the keepers from the roses you replace in two years.
Named roses that hold up here
Four roses give a good picture of what works, and each one passes the winter test without help. They differ in how they handle summer.
| Rose | Type | Winter here | Summer here |
|---|---|---|---|
| Knock Out | Shrub | No protection needed | Handles heat, good blackspot resistance |
| New Dawn | Climber | No protection needed | Vigorous, repeat blooming |
| Therese Bugnet | Rugosa hybrid | No trouble at all | Better in north Louisiana, bloom slows in heat |
| Hansa | Rugosa | No trouble at all | Better in north Louisiana, bloom slows in heat |
Knock Out is the rose most Louisiana gardeners can plant with the fewest worries. It is a repeat-blooming shrub that sails through the freezes the state gets and keeps its leaves through humid summers better than most. It is not immune to disease, though. Rose rosette, a virus, kills Knock Outs like any other rose. The Rose Diseases in Louisiana: What the Climate Here Actually Brings page covers what to watch for.
New Dawn is a pale pink climber that has been a Southern fence and arbor rose for generations. It survives winter without fuss, takes heat and repeats its bloom. Give it a sturdy support, because it grows large and fast. It also tolerates a little more shade than many roses, which helps on a bed that gets afternoon shadow from a house or a pecan tree.
Therese Bugnet and Hansa are the cold-country choices. Both are rugosas, valued for their fragrance and tough, wrinkled foliage. Winter is nothing for them here. Summer is the question. They do better in north Louisiana than along the coast, and they hold up best with afternoon shade in the hottest months. Plant them in full sun on the Gulf coast and expect fewer flowers and tired leaves by August. They make sense for a gardener who wants fragrance and hips and accepts a slower summer. For a bed that has to perform from May to November, Knock Out and New Dawn are the safer pair.
Sold here, but not for this zone
Garden centers in Louisiana buy from national suppliers, so the shelves hold roses chosen for a Chicago or Boston buyer. Some of them fail in Louisiana, though rarely from cold. Three groups on the shelf need extra work here.
The first is the hybrid tea. Bagged and waxed hybrid teas appear in late winter, and the blooms on the tag are real. In a hot, humid summer, many of them drop their lower leaves to blackspot and fade by midsummer unless they are sprayed. The second group is the English roses. Many were bred for cool, damp English summers, and in Louisiana heat the flowers open fast and shatter quickly. Some varieties do well, but the type as a whole is a gamble.
The third group is the cold-hardy Canadian and rugosa roses sold on the strength of their hardiness. A tag that says “hardy to zone 3” is proud of something Louisiana never tests. It says nothing about how the plant handles a September heat wave or a wet spring. The Explorer series is excellent in northern gardens. In south Louisiana, treat it as an experiment, and put it in the cooler parts of north Louisiana if you want to try one.
None of these will die from the cold, so the difference is in the work you put in. If you plant any of them, go in with a fungicide schedule starting at leaf-out, because blackspot arrives early in a humid spring and a rose that loses its leaves in June is weak all summer. Pick a spot with morning sun, good air movement and room around the plant, and water at the base so the leaves stay dry.
What to check on the label before buying
Two things on a tag or a bag tell you most of what you need to know.
The first is the grade. Bare-root roses are sold in grades, with the top grade the largest plants and the other grades smaller plants with thinner canes. Grade 1 costs more and gives a stronger first year. A potted rose is already growing, so check that the canes are green and the leaves are clean rather than speckled with black.
The second is whether the rose is own-root or grafted. Grafted roses have a named variety joined to a different rootstock, and the swollen join is the bud union. Own-root roses grow from their own cuttings, so every cane is the variety on the tag. The label may say “own root” or name a rootstock. If it says nothing, ask.
The colder the winter, the more own-root matters. A hard freeze can kill grafted canes to the ground, and what grows back from the rootstock is a different rose. An own-root plant that freezes back regrows as the rose you bought. Louisiana rarely cuts that deep, but north Louisiana freezes more reliably than the coast, and a late freeze after warm weather can do real damage. In sandy coastal soils, some Gulf South growers prefer a grafted rose, so a grafted rose is not always a poor choice here. Either way, look for “own root” or a named rootstock on the label and ask before buying any rose whose tag says nothing about how it was grown.
Checking this against your own county
Louisiana has parishes rather than counties, but the idea is the same. The LSU AgCenter is the state’s Extension service, with an office in every parish. The agents know which roses are doing well in local soil and which diseases are active in your area. A zone map covers the whole state, and a parish office knows your own block. Ask your parish office what is thriving locally before you buy more than a plant or two, particularly if you are planting a hedge or a row of the same rose.
Common questions
Do roses need winter protection in south Louisiana?
Most do not. A layer of mulch and a cover on the rare night when a hard freeze is forecast is usually enough. Roses that have started growing in a warm spell are the most exposed, because new shoots burn first.
Are Knock Out roses disease-proof?
No. They resist blackspot better than most roses, but they can still get it in a wet year, and rose rosette can kill them. Good spacing and watering at the base help keep them healthy.
Can I grow Canadian Explorer roses in Louisiana?
You can, but their strength is cold hardiness, which Louisiana does not test. Heat and humidity are the risks. North Louisiana gives them the better chance, and a spot with afternoon shade helps.
Is the hardiness zone enough to choose a rose?
No. The USDA system is based on the coldest nights of the year, and almost every rose passes that test here. Look for heat tolerance, leaf health in humidity and the grade and rootstock on the label.