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jumbojimmy

Buds keep rotting.

19 years ago

all my first year rose buds keep rotting. I don't know what causes them to rot. Hardly rain in Australia. Due to water restrictions, I only water my roses twice a week. Is there anything that can be done? Do I need to move them to a shady area?

Thrips are also a problem here.

This is a second flush of Falstaff, and the buds continue to rot:

{{gwi:336497}}

Comments (14)

  • 19 years ago

    If you can only water potted roses twice a week, I would definitely get them some shade. When we head toward the summer solstice, watering once a day is hardly enough for the potted roses, and they suffer. I would also hold back on the fertilizer.

  • 19 years ago

    I have self watering pots. I don't exactly know how those pots work..perhaps they act like a capillary action.

    The leaves look fine to me. They don't wilt in hot days.

    I only water the roots and never wet the leaves to prevent black spots from developing.

    I will take your advice and move my pots to a shady area when temp reaches 30+. It's spring here and the temp are about 20+.

    I'm thinking of using grey water soon (shower/cooking). That way I can water more than 2 days a week. Hopefully roses don't mind a bit of gray water.

    Thanks

  • 19 years ago

    I just posted the topic "If you enjoy a challengeâ¦" and one of my questions related to the same phenomena you have described (and pictured). I read that it can be caused by a disease called Botrytis Blight, and that preventing the disease entails removing the sour buds before they contaminate others (or fall to the ground). Certain roses I own were started as bare roots, and the rosebushes that have the most bud rot are almost exclusively those I started from bare roots earlier this year. Many other roses in my garden have no such problem, so I am not aware from anything I've read or experienced that lack of water or too much sun/heat would produce this.

    I too would like to move beyond simply trying to prevent the disease, to possibly curing it. Anybody have any luck treating this? We'd like to hear your thoughts & suggestions, please!

  • 19 years ago

    newsview 23 - thank you for naming this problem. Botrytis blight is new to me. Haven't heard of it before.

    Is the disease contagious?

    I've purchased 2 roses: Falstaff and A shropshire Lad from the same nursery and they ended up with this bud rotting problem.

    Whereas my other 3 bare-rooted roses don't have this problem, but instead heavily infested with thrips that cause browing of the petals.

    P.S I want to reply to your post but I'm no expert in rose growing as you can tell. THis is my 1st year getting hooked on growing roses. I'm totally addicted in this forum. I keep coming back here in search of new roses and hearing about people's experiences about rose growing.

  • 19 years ago

    Botrytis is a fungal disease, there is no "curing" it. Usually caused by wet or damp weather. You can try misting the buds with a fungicide just as the sepals (green covering) open. Most of us just deal with it until the weather heats up.

    Jumbojimmy, I would dump those self-watering pots. I'm suspicious that there is either too much or too little water in the soil. Watering by hand, while time consuming, gives better control and you can tell that the plants are getting sufficient amounts of moisture.

  • 19 years ago

    Botrytis requires wetting the flowers at cool to moderate temperatures. Dews persisting several hours can be enough moisture. It spreads by airborne spores. Usually there is more on the outer petals than the inner.

    Scars visible on the sepals in the picture might suggest thrips. You can have botrytis and thrips at the same time. Botrytis can invade wounds made by thrips.

  • 19 years ago

    Michaelg said "Botrytis can invade wounds made by thrips," which might explain the almost universal pink polka dots on Sally Holmes in our mild climate with moderate humidity.

    Jumbojimmy, if the only water you have is grey water, then that is what you must use. Don't get it on the foliage. Rose roots are far better equipped to handle the salts in grey water than the leaves. Roses planted in the garden soil are much better equipped to handle the salts in grey water than roses in pots. Really avoid using grey water on yellow roses. In my experience, they are salt-sensitive, as is multiflora rootstock. Modern hybrid teas and floribundas will handle grey water better than many of the older classes.

    I've guessing it is thrips. I believe Western flower thrips exist in Australia and that if they invade the buds early in their development, you might see that kind of damage.

  • 19 years ago

    Do you plan to keep the roses in pots or plant them in the ground? The pots look kind of small for a permanent home.

  • 19 years ago

    Well, these are my 1st year bare-rooted roses that I've planted in June(winter).

    I used 45cm pots (sorry not good with maths conversion). My second season with me, "Heritage" rose(pictured in the back,middle) did very well in the same pot size last year.

    {{gwi:336498}}

    However, I will be changing those pots next year in winter because that's when I'll be adding more bare rooted roses. Those newbies will use old pots, while the oldies will get much larger pots. Hopefully in 5 years time, I could have my own house. :)

    What seem to be the problem here is the buds keep rotting and the infestation of thrips. I've tried using pyrethrin(sp?), but those thrips keep coming back.

    A picture early this morning on my Cinderella rose which was sprayed with pyrenthrin yesterday. Noticed the browning, dull look on this rose bud. Could be Thrips or could be chemical burnt:

    {{gwi:336499}}

    And a picture of my A Shropshire Lad taken weeks back:

    {{gwi:336500}}

    This year's Spring is a HUGE disappointment.

    There hasn't been much rain in in Australia, so I don't think the balling or rotting is caused by rain. I only water the soil and never wet the leaves.

    Thanks for those comments. I'll see how it goes in Summer. For the meantime I'll have to continue with this pyrethrin spray to treat those freaking thrips.

  • 19 years ago

    You have some very handsome pots these are planted in. I still would try one experiment if you're as disappointed as you sound. I would get a very large regular container, drill extra 1/2" holes in the bottom and plant Falstaff in it and see what happens.

    All season I have wondered what was eating one rose I have that looks like yours. This rose is planted in the ground though. When I can get to a bud however and bring it in the house it opens very nicely. I noticed that when I cut the water down to the rose bush this quits and the blooms open just fine. When that area it's in gets too much water again, I start blaming this unknown pest again eating off the ends of the buds. None of the other roses in that area do this. I live in an area the summer is very hot and this rose is in full sun until about 5pm. Never thought to call it rotting buds though. So there's a thought for you to try. I believe it's just the pot keeping it too damp, different roses like different conditions.

  • 19 years ago

    Your roses look so healthy Jimmy! In spite of the bud-blast (I like your expression) When I was in between permanent homes I lived in a rooftop apartment and I also grew roses in pots. Believe me they did not look as good as yours. I have seen some roses do this (crisp) in hot climates, but the most likely explanation is thrips. Are the buds exposed to dew in the evenings?

  • 19 years ago

    I don't have any answers for you, Jimmy, but just wanted to say that the foliage on your roses look flawless. Hope the bloom problem clears up for you soon.

    Randy

  • 19 years ago

    Thanks everyone for the help here...

    After reading through what lesdvs9 and diane_nj were saying about those pots, I went out and investigate the problem myself.

    This is what I found:
    {{gwi:336501}}
    Roots are dangling out through these tiny holes of the black sourcer and SITTING on water.

    This is what the black saucer(whatever you call it) looks like:
    {{gwi:336502}}

    Basically, with those self-watering pots, this black saucer(sp?) is fitted INSIDE the pot so that the remaining water is trapped underneath and later re-filled the pot via capillary action. I think that's how it works.

    Is this good thing or bad thing?

    I mean, those pots do cost lots of money, and the people who invented them would know about this.

    However I know that plants like orchids don't like their roots soakingly wet.. Looks like l'll have to empty the excess water out so that the roots are not sitting on water.

    I don't know whether this is the actual cause of the problem here. I'll see how it goes by emptying out the excess water instead of reserving them.

    My biggest headache would be how on earth am I going to transplant these roses next year since most of their roots are dangling out through those tiny holes of the saucer.

  • 19 years ago

    jumbojimmy--

    I'm no expert of pots, but it sounds to me like need to transplant the roses into much larger pots. If the roots are growing out of the pot, the pot must be too small.

    Like you said, roots sitting in water is bad. Hopefully it will help if you pour off any excess.

    Good luck,
    Kate