Are Knockout Roses Disease and Insect Proof?

Yellow Knockout rose

This is a yellow Knockout rose. While the foliage may look pretty good, look closer. There’s yellowing foliage beneath the new growth and insect chewed foliage, and even some diseased foliage. What gives? I thought Knockout roses were bullet proof?!

Well, yes, so did I. And in my yard, most of them have proven to be. But certain roses, including this yellow Knockout (and Home Run, a rose that is supposed to be an Earth Kind rose but that is just about dead in my garden–go figure!) just don’t grow well.

That the yellow Knockout should be less vigorous makes sense. Yellow roses in general are weaker. It’s just a known genetic wrinkle. I’m not quite sure why that variation exists, but it does. And as yellow roses go, this is still a darned good one!

But contrast it with the Original Knockout, which towers over my head and which I have to whack back every year–including this “polar vortex” year.

Original Knockout

There’s quite a difference. Even my pinks, while not quite this vigorous (because I stupidly planted them under a tree which has now overtaken them!) are not spotted or insect eaten.

But oh well. I do love yellow so I’m willing to put up with a little imperfection. How else will folks know this is an organic garden?

A Rose That Didn’t Make The Cut

Flower Carpet flowers

Flower Carpet rose

A rose that I am traveling around with, but that I really don’t recommend, is Flower Carpet Pink Supreme.

I have a soft spot in my heart for the Flower Carpet roses. I planted the original pink one (Flower Carpet Pink) when we got married and it flowered and bloomed gamely even after it was over-taken by a Japanese maple. I seem to have a habit of planting roses too near trees and not remembering that they will eventually spread out to engulf them. My bad.

Anyway, this game little rose kept growing and throwing up ridiculously long canes for awhile and The Spoiler would remark, “Look at that tree blooming.” But eventually, I took pity on the rose and composted it.

It seems hard to believe that after that story I wouldn’t recommend this rose. It’s not that it’s a “bad” rose. It’s just that what’s come along since is so superior that there’s really no reason to grow this rose. This rose, because it was the first, doesn’t have the disease resistance of the later roses. And really, why struggle with black spot if you don’t have to?

There are valid reasons to grow this rose (other than sentimentality, of course). It comes in some colors that none of the others yet do. And let’s face it, we gardeners get into snits about our color schemes sometimes!

Flower Carpet Amber is a peachy color with yellow tones. Flower Carpet Pink Splash is a pink and white bi-color–no other series has a bi-color. And the Flower Carpet Yellow is especially vibrant.

So if you are looking for some unusual colors in a relatively easy care roses, give the Flower Carpet roses, in their distinctive pink pots a try. Just be sure to give them plenty of air circulation to avoid disease!

Earth Kind Roses

Red Fairy

This is a rose certification program from Texas A & M University. It is completely different from the roses that I’ve discussed so far because Texas A & M studies existing roses of all types for the same characteristics of drought tolerance, and pest and disease resistance. No breeding is involved, and no new roses are introduced.

In general, a rose that undergoes study in the Earth Kind trials spends 4 years at Texas A & M. It then spends another 4 years in various parts of Zones 7-9 Texas undergoing trials. There are now various Earth Kind trial gardens in other states as well (for those concerned, as I was, about the hardiness of these cultivars).

During the 8 year trial period, no fertilizer of any kind is permitted. No irrigation, after the initial year, is permitted. No pesticides are used. (In short, these roses are grown very much as if they are in my yard!)

A list of these roses can be found at the Texas A & M web site. The original Knockout® rose, for example, is one of the EarthKind® roses. Another common rose that is widely available that has been certified as an Earthkind® is a polyantha rose called ‘The Fairy.’ The photo above is of a version of the ‘Fairy’ rose called the ‘Red Fairy.’

The EarthKind® program has two types of climbers and three sizes of shrub roses currently certified. One hybrid tea has been found worthy of being called an EarthKind rose.

If you are searching for sustainable roses but are not currently in love with any of the offerings that the breeders have on the market, perhaps this is the answer for you. It certainly gives rose growers and lovers a variety of options.

Wordless Wednesday–What’s Wrong With My Rose Leaves?

damaged rose leaves with larva

Every year about this time (actually, slightly earlier) my neighbors know that I am an organic gardener because although I may have lovely rose blooms, my leaves look like those above.

Why? First of all, I’m not growing all Knockout roses, which don’t seem to get bothered.

But that’s not the answer you’re really looking for. If you look at the second leaflet on the lower right, you can barely see a tiny caterpillar-like insect. I have better photos from my post on the topic last year.

This is the larva of something called the rose sawfly.

Since it’s not a caterpillar, bt (bacillus thuringencis) doesn’t work.

The non-organic folks can use systemics to solve for this–but many of the rose systemics have the same neonicontinoids that may be implicated in bee deaths. So if you are non-organic, please reconsider this.

On occasion, and this year was one of those, I sprayed an OMRI certified herbal oil for this–just because the population seemed inordinately high. Insecticidal soap will also work–but again, spray at sunset so as to disturb as few beneficials as possible. Remember, these “good organics” don’t discriminate between good bugs and bad bugs–they just kill everything they land on–rose sawfly larva, spiders, bees–so try to spray when as few “good bugs” are around as possible.

I also had a caterpillar–a genuine one–eating my rose buds. That I really didn’t want. So I sprayed–at sunset, on an extremely cool day, when it was least likely that any beneficials might be around.

This is probably the first time I’ve sprayed the roses in 6 or 8 years. I really hate to do it–but when I do it, I try to do it responsibly!

Oso Easy Roses

rose & hydrangea

Another line of roses that I can highly recommend is the OsoEasy® Roses by Proven Winners. This is a growing line of landscape roses that comes in a wider variety of colors than any of the other offerings on the market. While Proven Winners advertises most of the roses as generally 1-2′ tall, mine have gotten easily 3′ tall–still a fairly dwarf size for a mature rose. They are hardy, disease and pest resistant and drought tolerant and they do bloom all summer as well. Currently there are 13 roses in this series and I believe Proven Winners continues to add roses each year.

I received my First rose, Oso Happy Candy Oh! (botanically Rosa ‘ZieMartinCipar’) in 2010. It came late that season and probably didn’t get into the ground until July. That summer was quite hot, with many days in the 90s and a few over 100. The bed I put them in doesn’t have ready access to water (like most of my yard) and because of my heavy clay, I don’t mulch because that just invites disease and fungus, rather than preserving soil moisture.

So to ensure you understand the picture, I plunk 4″ roses down into an unirrigated bed in the middle of a hot July and leave them to sink or swim. Got it?

They survived my New England winter and bloomed beautifully the next year, 2011. By 2012, they were blooming so beautifully (at top, with another Proven Winners shrub, the hydrangea, Invincibelle Spirit [again, botanically hydrangea arborescens ‘NCHA1’]) I didn’t know how I’d gardened without them!

Since 2010, Proven Winners has sent me two other roses in this series to test (Full disclosure: I regularly test shrubs for Proven Winners and they provide me with these shrubs). I have received Oso Easy Peachy Cream and Oso Easy Honey Bun, both roses in the peach, yellow, cream family (my favorite color family, just by chance). Both of these are still immature and not as prolific as Oso Happy Candy Oh! but they certainly have proved as easy and carefree in terms of watering requirements, and pest and disease resistance.

I cannot say enough good things about these roses. And yes, they too resist that nasty sawfly larva that so disfigures my David Austin roses. So if you’re looking for a rose that isn’t a Knock Out rose, this might be the one to try!

David Austin English Roses

Darby Bussell

Normally, I would not include any of the David Austin English Roses in the category of “Easy Care” roses. In fact, a lovely photo of leaves scarred by the sawfly larva coming up next week for “Wordless Wednesday” and it is in my existing bed of David Austin Roses. It’s a problem I’ve had with them for some time. It doesn’t keep me from growing them–it just keeps me from enjoying them to the fullest at their peak bloom, so I consider that a major drawback.

I was visiting a local garden center recently and came across two new varieties, the one I show above, Darcey Bussell, and Lady Emma Hamilton. Now since David Austin comes out with new roses every year, I gave them a passing glance and went on to get what I needed.

A few days later, I came across this post on Gardenrant about some David Austin roses that Elizabeth Licata had tried last year. For her they had proved to be disease resistant and continuous bloomers–just the thing I look for in an “easy care” rose. To my surprise, they were the same roses my garden center was offering. I ran back for the Darcey Bussell (who was a British ballerina–I looked her up) because it fit the color scheme of the other “easy care” roses I was testing this year.

From the moment I put the rose in the car (even before, really, because I’ve always adored the David Austin roses) I was in love. All the way home, I could smell this rose–that’s right this rose actually has a scent! Right there, that makes it different from every other rose I’ll discuss this month.

In addition, its blooms are larger and more “rose-like” in structure. In fact, they almost look like the old-fashioned cabbage roses.

They’re still not suitable as cut flowers because they are rarely borne on single stems–like most shrub roses, they are borne in clusters. But for me, that’s okay–more roses to love.

If this rose is half as good as promised, it will be fabulous. Now if I can just keep those pesky sawflies from finding it….