Shop Products
Houzz Logo Print
cmd_zone4

Disease-Resistant Rose

cmd_zone4
15 years ago

I just want to share what I learned today about shopping for disease-resistant rose. What I have to share may already be a known fact to our experienced rose growers but it may impart some knowledge to new rose growers out there, like myself.

I have read about Rugosa roses being resistant to black spots and powdery mildew but I also read that being disease resistant does not necessarily mean they'll never get these diseases in their lifetime. It may simply mean that if they get these diseases, the whole plant will not be engulfed. I went to Home Depot tonight and visited the garden center. There are only a few plants left but they still have two racks of container roses for sale at half the regular price - hybrid teas and rose shrubs. All of the hybrid teas are covered in black spots and of the rose shrubs, there were a few containers that are without black spots at all. I checked the labels and it says those shrubs are "naturally disease resistant." I almost cannot believe how healthy-looking these shrubs are - the leaves are clean, rose hips are starting to swell and there's still a couple of buds left. I got myself one and then I realized that if one wants to get a rose that is disease resistant, then one way to do it is to shop by the end of summer/early autumn, since this is the time that black spots and powdery mildew set in. It's a good indication of how the plant will look like at the end of the season. It's like getting roses in bloom to make sure you get the bloom color you want. My point is, if these shrubs can afford to look good at this time of the year in a container, when it's not getting enough care anymore, then they must look a lot better once they're on a well-tended garden with good soil.

Comments (9)

  • catsrose
    15 years ago

    Unfortunately, black spot and mildew can set in as early as late May/June. Also, you don't know when the shrubs were delivered vs the HT's. Most generic nurseries stock HTs for only Mother's Day and early summer blooming, but continue to stock knock-outs, the shrub most commonly carried, throughout the summer. So the HTs have been sitting around since June and the shrubs only since August. Not fair.

    The best way to find out if a rose is disease resistant, is to read about it. Go to helmefind.com/roses. Also, roses behave differently in different environments. For insance, a poster on the Antique Rose forum was just crowing about how beautiful her Bourbons are this year, but many of us here in Virginia are about to throw in the towel on them.

    Yes, resistant does not mean free from.

  • scardan123
    15 years ago

    well, I am usually healthy too, but if you make me stay naked in the snow then I'll get a flu.
    Same thing for roses: one shold not forget they have certain requirements about sun and exposure.
    This said, there are huge differences in resistance from rose to rose ALL ELSE EQUAL.
    Besides, a rose which could perform well in a climate, could be plagued ad miserable in a different climate.

    Not all rugosa hybrids are very healthy, I've about 50+ rugosas so I know what I am talking about.
    Alba, Rubra, Scabrosa and roseraie are always healthy. Agnes and many of the pavement rugosas too, but not all of them.
    Hansa gets some disease, grootendorst and Robusta get many diseases (despite the name "robusta").

    If you want carefree roses, and live in a cold area, use knockout (single and double, red and pink), and these 4 rugosas: alba, rubra, roseraie de l'hay, scabrosa.
    If you live in a warm area, replace the rugosas with chinensis mutabilis and old blush.
    All these roses are also drought resistant, TO BE ROSES. They are not desert plants, but they will be still alive when all the other roses will be dead.

    Besides, Meilland has introduced a line of carefree roses which are called -for the italian market- "do nothing".
    Omen nomen. Go for them. They are usually used along the public roads, with no maintenance, together with Oleanders.

  • Kimmsr
    15 years ago

    If you plant any rose in a "conventional" garden soil (an really unhealthy soil) that plant will be more likely to get plant diseases, including Black Spot, and be bothered by insect pests. But if you plant that same rose in a good, healthy soil, one well endowed with organic matter that is evenly moist but well drained and is in the optimal pH range with a well balanced nutrient load, those roses will be much less likely to get any plant disease or be bothered by any insect pest.
    The soil plants grow in is the key.

  • sirilucky
    15 years ago

    There is nothing quite as lovely as a rose bud unfurling, framed by lush, healthy, deep green foliage.
    So, what is disease resistance? Simply put, it is a plants natural ability to withstand infection from a variety of pathogenic (disease producing) microorganisms - fungi, bacteria, virus and virus like organisms, and pathogenic nematodes. Plants have varying degrees of resistance; some are completely immune to infection by common diseases, others partially susceptible to infection. There are no roses that are completely immune to all diseases under all cultural conditions.
    Preventing Common Rose Diseases:
    The key here is to prevent trouble from the beginning. To control black spot on roses and other diseases,there are certain things you can do, right from the start, to prevent or minimize troubles.
    Number one, is to choose tough roses that are suited for your particular region.If your summers are quite hot and humid, buy only varieties that do well and thrive under those conditions.
    Get advise from a good local nursery with a knowledgeable staff. They will guide you to the correct plant selections.

  • plan9fromposhmadison
    15 years ago

    Good strategy! All things being equal (as in, all roses having arrived at retailer at the same time), that's a good rule of thumb.

    However, if the roses seem to have been stressed, I would still not buy those particular plants, but would, instead, note the names, and order own-root examples from a trusted rose grower. Stress can leave roses vulnerable to far worse (and more incurable) diseases than Blackspot. You don't want to introduce those diseases into your garden.

  • Kimmsr
    15 years ago

    Why is it that Rebecca Coles, Lee Reich, Ann Kovejoy, P. Allen Smith, and many other garden writers tell you to make your soil good and healthy so strong and healthy plants will grow in that soil? Articles in Fine Gardening and Garden Gate magazines as well as Organic Gardening magazine have been written for several years now about how growing plants in soils well amended with organic matter will produce strong, healthy plants better able to fight off plant diseases and insect pests.
    While plant genetics can help in disease resistance, growing plants in a good, healthy soil is much better. Hybrid Teas have had tolerance of diseases bred out of them.

  • schifferle
    14 years ago

    I seem to be the only person in the entire rose gardening world that has Roseraie de l'Hay that gets BS. Nothing on my Rugosa Alba & Rubra. They're always fine. Quietness and Kiss Me are doing well, too. I have no idea why my 3 Roseraie de l'Hay get BS. Can't spray them (if I can & not hurt them please let me know), but I do everything else I know to help prevent problems...not planted close together, do clean-up, feed them, etc.

  • scardan123
    14 years ago

    Schifferle, are you sure yours is RdlH and not Hansa? Some nurseries sometimes sell one for the other as the blooms are very similar, but Hansa gets BS (or at least I learned so from Olga, fortunately here they are both perfectly healthy).

    Cmd_4, probably the best thing is to start with a mix of potentially very tough roses, then try them in your garden, and see what happens. I have tried many before finding those best suited for my climate. I am still going on with trials, to increase the numer of sports I grow.
    Try to plant them all in optimal conditions, considering sun, air circulation, and soil composition. That's important. If you give them the best conditions they will give you the best performance.

  • lovesdaphne
    14 years ago

    I am new to this forum. I have several different varieties of roses. I love roses, and I try to buy "extremely disease resistant" because of our moist climate. I find that the plants invariably end up with black spot. I carefully remove all the leaves I can find, sometimes leaving the plant with hardly any leaves! I am going on three years now, this year I think a couple of them really look much better but I am about ready to give up on them I am so tired of going around taking off all the diseased leaves! And yes, I do wash my hands between plants and I clean my pruners (learned that the hard way!). I have a climbing variety (don't have the name handy at the moment) that started out looking pretty good early on this year (I've had it for 3 years). It is fairly shaded, but when I bought it I searched for a climber that could tolerate shade. It is putting out tons of blooms and looks good from a distance but up close it is a mess! I have put so much work into that plant, but it is beating me down! Any tips for the winter, other than building up the mulch at the base? Any tips on a good "fertilizer" or treatment that doesn't stink, preferably organic? Also, do roses that are supposed to be shade tolerant every really shade tolerant? Also, the aphids. I bought tons of lady bugs the last couple of years, let them go in my gardens and when I look for them a week or so later, they are nowhere to be found? Any suggestions on that one?