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What is the problem with my roses?

Posted by senore100 (My Page) on
Tue, May 17, 11 at 2:13

Hi,
I planted some roses toward the end of last year. They were doing good. However, this year, they seem sick. Please see the pictures below:
Pic 1
Pic 2
Pic 3
Can someone kindly give me some idea what the problem is? I suspect it's some bugs. But not sure. Anything I may get from Home Depot to help combat the problem? Thanks so much in advance!
Jeff


Follow-Up Postings:

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RE: What is the problem with my roses?

Hi Jeff,

While we're waiting for a more experienced rose grower to reply, maybe you could give some more information such as what type of rose you have and how you have been caring for your plant. Also check out the FAQ at the top of the forum. There's an answer to a question about pruning roses that also includes some basic rose care info for the desert.


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RE: What is the problem with my roses?

Thanks haname.
Well, honestly I don't know what type of roses they are. But they are both tea roses, one red and one yellow. I got them from Home Depot toward the end of last year -- I just assume they are of the most common types.
They bloomed when I first got them. During the winter I watered them 15 minutes once a week. Toward the end of February, I cut them back, and they both seemed to take it well. Then they started to grow back as the weather grew warmer. I also gave them some slow-release fertilizer (15-7-7). They started to grow quite a bit of leaves. Then I realized they probably would need some potassium -- too much nitrogen may only promote leaves at the cost of blooms. So I gave them some banana peals. So far I am still not seeing any flower buds yet. Nowadays I keep a 15-minute once every three days watering schedule.
I am not sure when all this problem started. Maybe about two months ago. But the color of the leaves seems a bit washed out. It looks to me like there are some bugs that bother them. Interestingly, the gardenias and hibiscuses that sit next to them don't have such a problem.
I will go ahead and read up on the FAQ section. But I would still really appreciate it if someone can give me some ideas about what the problem is and how to fix it.
Thanks!


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RE: What is the problem with my roses?

I love roses and have about 25 of them T's, climers & old fashions. 1) where are you located that you water for 15 min every 3 days. In Camp Verde once every 5 days for 3-4 hours on a drip(1gl per 1/2hr) Will increase as it gets hotter.
Looks like old powdery meldew/black spot you can get a Ortho spray at HD for that. Follow the intructions, you will need to spray real good(top and bottom of leaves) about every 5-7 days until the fungus is gone. The damaged leaves will never look good but the new leaves s/b pretty. So buy a large bottle or get consentrate& a sprayer. When watering,water the ground NOT the leaves. If you must get them wet, (sprinkler) do it in the early morning so they will dry fast. As for the blooms, roses like lots of fertilizer. I use steer manurae, then use fish emulsion(my roses favorite)(Alaskin@Walmart)then granuals. Roses are not picky, I have even used lawn fertilizer on them. You will always have apids and grasshoppers like to eat big chunks out of the leaves, maybe thrips on the white roses but thats about it. Once you get the hange of it roses are pretty easy and I am always good with easy.


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RE: What is the problem with my roses?

Instead of pruning in February, prune in late October to give them all winter to grow.

Water them deeply and less often. Your current schedule it too little and too often. Use a moisture meter to see how wet the soil is, and for how far away from the plant.

They do need iron - my dad used to use ironite on them. Soil sulfur also helps.


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RE: What is the problem with my roses?

campv, thanks so much!
I live down in Chandler. The roses are old-fashioned tea roses (not the climbing type). I have them on the north side of my house against a wall facing east. So they will not get afternoon sun.
Since I am not seeing any leaves yellowing, it seems that they have enough water. They both seemed to be doing pretty good when I first got them last year.
I will go get the spray from HD and see if it will help cure the problem. Thanks a bunch!


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RE: What is the problem with my roses?

Chandler-you will lose the damaged leaves and they will turn yellow and drop. But the nice new ones will take their place. I still believe you are not giving them enough water. Lazygardens is right "to little to offten"
Please try the fish emulsion its everything in bottle. $6 @ walmart. I think HD cost more. Should last you about 2 years, it only last me 1 because I have so many roses. I got roses this year that were 7" across and nieghbors taking pictures. Its not me it's the fish stuff. The ortho fugiside or garden disease control will take care of any kind of leaf problems. Meldew, rust, black spot etc. and can be mixed with malathion for any varmits. I start cutting my roses back in Jan. because it takes me about a month to get it done, also it is much colder here. Connie


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RE: What is the problem with my roses?

Thanks so much, lazygardens and Connie! I really appreciate your help!
I actually had the watering schedule as once every four days. Then one day I had a contractor coming over to work on something else around the house. Then he observed the white-colored salt on the gravel (as mulch) and suggested I instead water once every three days. That's why I changed the schedule. Indeed I have read all about watering in low desert, but since I've got no experience....
Definitely I will try what you both have suggested and hopefully can get the roses cured real soon! Thanks again!
Jeff


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RE: What is the problem with my roses?

I hope I'm not too late in replying to your question.

These leaves show salt damage, sun/heat damage, powdery mildew and spider mite activity. No chemical sprays or fertilizers should be used as we head into 100 degree temps.

New roses do need less water, more often. As the garden establishes, reduce the number of water cycles but increase the length of each cycle. In the cool winter months, my established beds received 5-7 gallons of water per bush once a week. In the hot summer months, they receive 5-7 gallons per med-large bush 3x per week. You said 'tea roses' but I'm guessing you meant hybrid tea roses. Usually 5 gallons per cycle 3x a week will be ample for them. Deep watering is crucial to keep the salts, found in fertilizers, city water and our alkaline soil, from building up in the root zone. Take a sharp stick and put it into the soil at the leaf line within a few hours of watering. It should be easy to push to a depth of 14 inches. If it doesn't go that deep, you've hit a rock or you need to increase the water per cycle.

While powdery mildew may continue to be a problem for some bushes during the summer months, it is rarely a problem during sustained temperatures of 80F+. A fungicide sprayed at the beginning of spring usually keeps it manageable.

Fertilizers should not be applied to roses during summer months. An application of slow-release, like Osmacote, should provide ample nitrogen. Too much nitrogen does far greater damage than too little in warm soils.

Spider mites are a summer pest and only a miticide or arachnicide will have any impact. Their life cycle is very short so a jet spray of water to top and bottom of the leaves 3x in one week will take care of them. Chemical sprays should not be used on windy or hot days.

I see you have a gravel mulch. Gravel holds heat and reflects sunlight. Pulling that gravel back beyond the leaf line of the bush and using a forest product for mulch will retard the weed growth, reduce water evaporation and keep the roots cooler.

Do not apply any iron until cooler fall months and do not prune new roses until late December/early January. We do a light fall pruning in late September/early October but new roses should always be allowed 1-2 years in ground before hard pruning.

Hope this helps. There are five local rose societies and we each have websites to help people grow the best roses they can. You can certainly email me with any questions, too.


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RE: What is the problem with my roses?

Re: fish emulsion. How often? What part of the year?


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RE: What is the problem with my roses?

How much, when to use and how often is determined by temperature and the plant. In my garden, I'll use fish emulsion on my roses in early April and late October, when I'm applying chelated iron (not Ironite)and alfalfa pellets (or mixed into alfalfa tea). It's a good, stinky liquid glop that roses really love but used too often and you may attract dogs, cats, critters, flies, etc that actually like the smell. There are a number of liquid, organic and granular fertilizers specifically sold for roses but the N-P-K numbers on the label should be the determining factor. Deep-rooted plants, like roses, aren't going to benefit from a high phosphorus number (the P) as phosphates bind with soil instead of roots and don't soak in with water. After pruning roses in January, I apply super phosphate directly into the rootzone at about 6 inch depth by auguring 3-4 holes some 6-14 inches from center.

A high nitrogen (N) number is needed during the fall and spring active growth period but will burn roots and foliage when soil temps are higher in summer and won't be used by roots at all in low soil temps.

Potassium is in most fertilizers and is usually a low number. I haven't met anyone yet that has needed to add more potassium to their rose garden than what is included in fertilizers and compost. While bananas and potatoes are known for their potassium, both have to be composted before applying to a rose bed.

As far as I know, other non-native plants can benefit from fish emulsion during their active growth times, too, which may be summer or winter, depending on the plant. I use it on my violets in December but not my roses which are going dormant at that time.


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RE: What is the problem with my roses?

Whow, moroseaz! That is an awful lot of information! Thanks so much! You are right -- I believe mine are hybrid tea roses. "5-7 gallons per med-large bush 3x per week", that seems a lot of water! I suspect that water does not drain that well in my case, because I had manually dug holes for my new plants here. What I've found is that the clay is really hard, and it's probably difficult for water to seep through.
I do see white coloring in the gravel, and have been told by someone that it's the salt and I should increase the frequency of watering accordingly. Actually I've also been told that I should have had a layer of sand at the bottom of the hole before I planted anything...
Referring to what you said, I don't understand how deep watering will help prevent this salt problem. What if I've got a draining problem at the same time? Will an increase in water only lead to too much water?
Thanks again for all the kind help!


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RE: What is the problem with my roses?

If you only dug a hole large enough to accommodate the plant at the time you planted it, too much or too little water will have about the same effect (no growth, early death). Holes for large flowered roses (hybrid teas, grandifloras, some other classes) should be at least 24 inches square and 16-18 inches deep at planting.

If hole was really tough to dig, ie pickax, a layer of sand at bottom will help drainage, along with a chimney hole to hold the water and drain it below the caliche or hardpan. Soil from hole should be mixed with a fine-grade compost. Ideal soil composition for roses is sandy loam with a pH of 6.5 to 6.8.

Back to the water... your leaves show no indication of overwatering... pale colored, weak growth, no brown. The leaves do show brown tips which is indicative of shallow watering, where salts build up in the leaves during transpiration on warm/windy days.

The only way to judge whether your roses are receiving too much water is to look for the pale (whitish), weak growth (don't confuse with iron deficiency which is more like green veins in yellowing leaves). There will also be a distinctive rotting smell in the soil. When planting roses, dig the hole, fill halfway with water and time the drainage. If it doesn't drain within 6 hrs, you have a problem and the sand and chimney become beneficial. If it drains, you don't need them.

While 5-7 gallons may seem like too much water to you, measure that out and see how little it really is to your roses. A 4inch deep berm about 2.5 ft across probably won't be full at 5 gallons.

Try the sharp stick penetration of the soil after watering. If it sinks easily, the roses are receiving adequate water. If it doesn't penetrate to 14inches, increase length of water cycle.

This fall or next winter, you may wish to semi-excavate those roses and mix the soil on the outer edges of the roots with compost and maybe some soil sulfur and bone meal. Do not add gypsum for roses. We have enough calcium in the soil. Save the gypsum for your veggie garden where the soil gets turned. As roses get larger, increase the volume of water in the roots. Roots grow where water flows. Within a year, the roses will show noticeable growth, girth and health.

On average, the most common reason for rose death down here is lack of water followed by root competition from trees and other shrubs looking for that same water.


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RE: What is the problem with my roses?

moroseaz, thanks so much again! Sigh, I wish I had known half as much as you told me when I planted the roses last year. I dug holes probably deep enough, but obviously not big enough, and definitely did not time the drainage...
I will use a sharp stick to see if they are getting enough water or not -- since they are sitting against an east-facing wall on the north side of my house, they are not getting a lot of afternoon sun.
Also I would like to try the semi-excavation this fall to give the root system some more breathing room.
Just these few days I've seen some aggressive leaf growth in both roses, although the old leaves still look pretty much the same. I guess it's not a bad sign!


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RE: What is the problem with my roses?

Glad to be of help! If you can make either the Mesa/East Valley or Phoenix Rose Society meetings in June, there will be lots of people asking and answering questions about summer rose care. The other 3 rose societies (Scottsdale, Glendale & West Valley) don't meet again 'til September, at which time we'll all be asking and answering questions about resuscitating our roses after the summer.

While meetings are free, of course, dues are about the cost of a rose bush or two and include a monthly newsletter. Four of the societies maintain 5 public rose gardens, too, and we strongly encourage everyone to visit one, even in the hot summer. You can see how the roses tolerate heat and note any summer pest/disease problems. Some roses fare quite well and you may want to remember those particular rose names when making future purchases.


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RE: What is the problem with my roses?

Thanks moroseaz!
Is there a website for the roses societies that I can visit? It sounds interesting. I would like to go to the meeting if it works with my schedule. Thanks again!


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RE: What is the problem with my roses?

Of course!

Phoenix - www.phoenixrose.org, meets 3rd Tuesday of month, 7:30pm, Valley Garden Center,1809 N 15th Ave, Phoenix
West Valley - www.westvalleyrose.org, meets 2nd Tuesday of month, 7:00pm, LandscapeMart, 8028 W Thunderbird, Peoria
Mesa/East Valley - www.roses4az-mevrs.org, meets 2nd Thursday of month, 7:00pm, MCC Library, 1833 W Southern, Mesa
Scottsdale - www.scottsdalerose.org, meets 2nd Wednesday of month, 7:30pm, Eldorado Comm Ctr, 2311 N Miller Rd, Scottsdale
Glendale - www.roseglenaz.com, meets 1st Thursday of month, 7:00pm, Glendale Women's Club, 7032 N 56th Ave, Glendale


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RE: What is the problem with my roses?

Cool! Thanks! The one in Mesa is too far from where I live. I really appreciate your help moroseaz!


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