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ROSE PROBLEMS/BLACK SPOT/ Etc

Discussion in 'Roses' started by wiseowl, Sep 5, 2017.

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  1. wiseowl

    wiseowl Friendly Owl ADMIN Staff Member

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    IF ANY MEMBERS WOULD LIKE TO SEE ANYTHING ELSE ADDED TO THIS THREAD THAT WOULD BE ADVANTAGEOUS PLEASE JUST ASK.IF ANY NEW TREATMENTS BECOME AVAILABLE THEY WILL BE ADDED.
     
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      wiseowl Friendly Owl ADMIN Staff Member

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      BLACKSPOT
      The fungus is genetically very diverse and new strains arise rapidly. Unfortunately, this means that the resistance bred into new varieties usually fails to last because new strains of the fungus arise to overcome it.

      Large black or dark purple spots on the surface of the leaves or stems are the main signs of black spot. As the problem gets worse the foliage gradually turns yellow and drops prematurely, weakening the plant.


      Plants affected
      Rose black spot is an extremely common and widespread fungal disease of both cultivated and wild rose varieties.
      Rose black spot is specific to roses and all types are susceptible.
      The disease causes dark spots or irregular brown or black blotches on both leaf surfaces. Leaves then turn yellow and drop prematurely, resulting in weakened plants.
      The disease is worse in warm, wet weather.
      The black spot fungus produces spores which are released under wet conditions and usually spread by rain-splash.
      The disease can also be passed from plant to plant on hands, clothing or tools.
      Spores overwinter mostly on the shoots, but can survive on fallen leaves and within the soil.
      Recently, rose black spot has become more common in town and city gardens due to less sulphur dioxide within atmospheric pollution. Sulphur is known to reduce fungal problems.

      I don't use any forms of chemicals on my Roses

      Chemical
      Products containing the following chemical ingredients are all effective on Rose black spot
      Penconazole
      Myclobutanil - alternating any of these with the protectant Mancozeb to prevent the fungus developing resistance to the fungicides.
      -----------------------------------------------------------------------------------------------------------

      Organic
      Remove infected, fallen leaves promptly and burn.
      Hard prune shoots in spring and burn the prunings.
      Treat infections with powdered sulphur, which is deemed organically acceptable.
      Some cultivars are partially resistant to black spot but in a bad year all varieties may succumb. Generally, many of the older cultivars and more yellow than red or pink cultivars are susceptible to the disease. So checking catalogues and choosing resistant varieties, such as 'Bonita', 'Royal William' or 'New Dawn', and growing a mixed planting should help. Rose varieties less than five years old should be relatively disease resistant.
      --------------------------------------------------------------------------------------------------------
      Prevention
      Prevention of rose black spot is very difficult and many strains of the fungi are resistant. However, regular raking around the plant with a hoe and pruning and burning of infected material will certainly help along with the advised treatments.

      Choosing resistant varieties also helps, but don't rely too heavily on resistance because there are many species of fungus and even new varieties can quickly succumb.

      Adopt a regular, fortnightly spraying regime to protect your plants before the problem begins. It's a good idea to alternate the chemical that you use to prevent resistance occurring.

      Dig in plenty of organic matter at planting time and keep plants well fed throughout the growing season. Strong healthy plants will generally resist attack better those that are weak.

      Surround plants with a fresh layer of mulch each spring. This will smother any spores that have fallen around your plants and stop them from being splashed on to roses by rain.​
       
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      • wiseowl

        wiseowl Friendly Owl ADMIN Staff Member

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        Mildew

        ORGANIC/TREATMENT
        A white powdery substance found on the rose leaves or tips of shoots or buds. Most commonly found when the weather is warm but moisture is present, usually spring and autumn. Most tropical regions with constantly high humidity will find mildew a problem in roses. Highly fragrant rose varieties are more susceptible. One of the best natural sprays is milk - 1 part milk to 10 parts water sprayed on the leaves which can transforms the white power to a grey/black appearance which shows it has killed the Mildew spores. Can be used once a week. If very humid and need more control use ‘Triforine’ a systemic fungicide which is absorbed into the plant, or ‘Mancozeb Plus’ or ‘Eco-rose’ which are contact spray onto the leaves. In severe cases plants can be defoliated by mildew and control must be taken. In tropical areas a selection of mildew resistant varieties should be considered. Highly fragrant varieties do suffer more than non-fragrant types.
         
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        • wiseowl

          wiseowl Friendly Owl ADMIN Staff Member

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          RUST

          Rusty-red spots are found mainly on the underside of the leaves. The leaves show small yellow spots, on touching the rust will leave an orange powder on your fingers. Only in severe cases will plants affected with rust lose vigour, but it should be treated when it appears, mostly in late autumn. Worth trying a milk spray - 1 part milk to 10 parts water sprayed up under the leaves to contact the rust area. The best fungicides to use are ‘Triforine’, or ‘Mancozeb Plus’, or ‘Eco-rose’. These sprays will kill the spores. Best if sprayed under the leaves for direct contact with the pustules. Rust is a problem mainly associated with a small number of rose varieties and only in certain weather conditions.
           
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          • wiseowl

            wiseowl Friendly Owl ADMIN Staff Member

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            APHIDS

            Thick colonies of insects found on the new shoots and buds in early spring and sometimes autumn. They suck into the shoots, can distort the flowers and leaves, also leaving a sticky residue on the leaves. This attracts ants which ‘milk’ the aphids for the ‘honey dew’ residue. Ants move the insects to other parts of the bush spreading them wider. Squirt the insects off with water jet from the garden hose, or spray soapy water over the insects. Rub off small colonies with fingers. Natural predators will help reduce these pests - Parasitic Wasp, Ladybirds and their nymphs, hoverflies, and birds all control these insects very well. Other options are ’Pest-Oil’ (not white oil) or ‘Eco-Pest Oil’ (a vegetable oil) which all coat the insect with oil and suffocate them, soapy water does also. If in plague proportions use ‘Confidor’ which is of low toxicity.
            Nature does a lot to help reduce aphids – wind blows them off, rain washes them off, but the little predators are our best friends in the rose garden.
             
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            • wiseowl

              wiseowl Friendly Owl ADMIN Staff Member

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              THRIPS

              Blown in with hot north winds mostly in early spring. Pale coloured petals show brown damage. White roses look dirty. Millions of ‘specks’ on petals. Blooms don’t open, petals stick together. No easy remedy. Believed to blow in from harvested paddocks and dry roadside grasses. Mostly effects the early spring flowers, but new growth will follow with clean petals. No cure, if spray one day fresh insects the next. Very disappointing to see the damaged flowers, particularly if roses only flower in the spring. This is one of the rose problems which although unsightly is best to just accept for it is no major problem and very short lived.
               
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              • wiseowl

                wiseowl Friendly Owl ADMIN Staff Member

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                GROWING ROSES IN CONTAINERS
                Only a few roses are tolerant of being grown in containers, as roses generally have long shallow roots for anchoring the plant and searching out moisture and nutrients. As long as deep containers are chosen, a good show of blooms should be achieved.

                The best roses for growing in containers are the patio and miniature types, which can be grown in fairly small but deep pots 23-35cm (9-14in) deep. You could also try growing less vigorous, more compact ground cover and climbing roses, but use larger containers with a minimum depth of 30-45cm (12-18in).

                The best compost to use is a loam-based John Innes No 3 to which 10 to 20 percent multi-purpose compost or very well-rotted manure may be added for richness. Position the container before filling with compost as it may be too heavy to move once planted up.

                Roses love sunshine and should receive sun for at least half the day. However it is important that container-grown plants do not dry out or they will become prone to powdery mildew. If possible position the container so that it is shaded for part of the day, leaving the plant itself in full sun.

                Ideally pot up plants in November using bare-root plants, but container-grown plants will do as well, and can be potted up any time between October and April.

                Drainage: Keep the pots raised on feet and add a drainage layer of gravel at the bottom to ensure good winter drainage
                Feeding: Roses use up food reserves quickly and grow better if top-dressed each spring with a granular rose fertiliser. Additional feeding may be required as per the manufacturer's recommendations. Avoid feeding after August as soft growth may be damaged by cold winters
                Mulching: Mulch with a 5cm (2in) top-dressing of well-rotted garden compost or manure to help retain moisture and enrich the compost
                Top-dressing: Every second year, remove the top 5cm (2in) of compost and replace with a fresh layer

                The Potted/Container Rose

                Roses were first sold in pots, as were most plants, to fulfil the demands of the instant gardener but the traditional method of supply is as bare root plants in the winter months, often by mail order. There is little between them as far as the ultimate plant is concerned but there are advantages and disadvantages to both.


                As already mentioned, a container rose can be purchased at any time of year (although there are more available in the summer months for various reasons). The advantage of buying a rose in a pot is that you can select the plant yourself during a visit to a nursery oo garden centre. Remember though that the range will be smaller than the range available in grower’s catalogues. A potted rose planted during the summer months will require much more watering than a bare root rose planted in the previous autumn. So tragic to go away on holiday leaving a beautiful new rose only to find it withered or even dead on return.

                Bare root roses can be chosen and ordered at any time of the year, though early in the summer is best to ensure that your choice is secured (growers tally orders and the roses available as the orders arrive on a first come first served basis). However they will only ever arrive in their dormant season, usually between the months of October and March. Therefore the first flowers will not be seen until the following year. Obviously they are live plants so need fairly immediate treatment upon arrival. This can be difficult in times of heavy frost or snow. (It is prudent to prepare an area in which to heel in the roses -more on this later). Bare root plants do tend to transplant more easily and have a settling in period before they are required to grow or flower. I would never advise buying a pre-packed rose from a supermarket for you have no idea how long they have been packaged and may well have dried out

                Advantages of Bare-root plants:
                • You pay less for the same size plants.
                • You can carry and plant them easily.
                • You only plant them in winter, so they need less maintenance after planting. The ground is naturally wet for their first few months.
                • You get the biggest selection: Many Roses are not sold pot-grown.
                • They are "asleep" in winter - this is the best time to transplant any Rose

                • Advantages of Pot Grown plants
                • Pot grown plants can be delivered & planted all year round

                POTS

                Terracotta is made from clay – which is just a kind of soil – that is turned on a wheel and fired in a kiln. The hotter the firing, the more frost-resistant it will be. This is important because terracotta can crack and flake in very cold weather because the pots absorb water which then expands as it freezes and something has to give.Opt for a pot that provides good drainage. Plastic and clay pots with holes at the bottom offer better drainage ,and I always use John Innes No3 to plant my Rose
                Place a one-inch layer of medium-sized bark chips or gravel over the bottom of the container. The chips or stones should be larger than any holes in the bottom of the pot to prevent them from falling through. This layer provides your roses with additional drainage.
                Loosely pack the soil into the pot. Do not pack too tightly, as your rose needs room to breathe.
                Increase the nutrient level by mixing a cup of bonemeal into the soil. Roses need a lot of nutrients, and bonemeal can provide the fertile conditions your roses need to produce many blooms.Place the rose into the soil. If working with a bare-root rose, spread the roots out comfortably. Rose roots need ample room to spread out horizontally.
                Fill in the area around the rose with more soil. Gently press the soil around the stems. The surface of the soil should match the place where the roots and rose plant meet.The container should be filled so that the soil almost comes to the top. If the rose is too deep in the container, pull it out of the soil and add more to the bottom of the pot.Water until well saturated. Even though root rot does pose a threat to roses, these flowers also need plenty of moist soil to survive.Position the container in a location that receives full sun. Roses need at least 6 hours of sun daily to thrive.
                 
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                • wiseowl

                  wiseowl Friendly Owl ADMIN Staff Member

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                  SHRUB

                  PRUNING YOUR ROSES
                  Pruning roses is intimidating to many gardeners, but actually very good for the plants. but keep in mind that it is very hard to kill a rose with bad pruning. While there is a great deal of disagreement among rose experts regarding how and when to prune roses, it is generally agreed that most mistakes will grow out very quickly and it is better to make a good effort at pruning roses, even if you make a few mistakes, than to let them grow rampant.

                  WHY DO WE PRUNE OUR ROSES

                  To Encourage new growth and bloom.To remove dead wood To Improve air circulation
                  To Shape the plant.

                  18cc0b5799bb2ccd75941b9f866888b0--trimming-roses-trim-roses.jpg




                  789-Rose-Pruning-Diagram.jpg
                   
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                  • wiseowl

                    wiseowl Friendly Owl ADMIN Staff Member

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                    PRUNING A CLIMBING ROSE

                    A good rule of thumb for pruning climbing rosebushes is to not prune them for two or three years, thus allowing them to form their long arching canes. Some die-back pruning may be required but hold it to a minimum! The two or three years is a “training time” for you to keep them trained to a trellis or other feature of your garden; keeping them tied back and growing in the desired direction early on is of the highest importance. Not doing so will cause you much frustration in trying to train the rosebush to go where you want it to once it has grown truly out of control.

                    While growing in those first years, keep an eye on where the canes are growing and help train them by tying them back to the support structure you have chosen.
                    1. Selecting and encouraging strong growth from the base of the plant.
                    2. Training stems so that they fan out and are near to horizontal to promote shoots along the stem
                    3. -------------------------------------------------------------------------------------
                    • Step 1 – cut away any growth that is growing away from the structure that cannot be tied back.
                    • Step 2 – the ‘four D’s’ – remove any dead, dying, damaged and diseased stems.
                    • Step 3 – pull down the longer stems to 45 degrees or more and tie against your wires.
                    • Step 4 – remove any remaining leaves to reduce the risk of disease spores being carried over.
                    • ---------------------------------------------------------------------------------------
                     
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                    • wiseowl

                      wiseowl Friendly Owl ADMIN Staff Member

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                      Best Time to Cut Roses for a Vase Display
                      The best time cut roses is when they are about one third of the way between a fully closed bud and full open bloom. By the time they are fully open it is too late and they will soon drop all their petals.

                      As soon as the cut end of the stem is exposed to air, it effectively creates a seal which prevents water being taken effectively. To overcome this and allow the rose to last as long as possible, recut the stem at an angle and them lower into a couple of inches of just-boiled (but not boiling) water for about 30 seconds. Keep the buds away from any steam, and then place them in a vase.
                       
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                      • wiseowl

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                        POT SIZES

                        Capture.JPG
                         
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                        • wiseowl

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                          MOVING YOUR ROSE

                          You are about to find out if the rose you hoped would be a tidy little spot of color next to the path is going to be just that, or it’s going to be a rampant monster snatching the shirts of people’s backs as they walk by.When this happens you are faced with two choices. Cut it back or move it.​
                          Well Woo would move it,I don't like cutting back a Rose just because it has grown to its mature size and its in the wrong place,it will stress your Rose out and you won't get as many blooms on it.

                          In the middle of the hot summer????
                          Yes I know it would be best to wait until winter and move it right before pruning time. but if this Rose is really in the wrong place then move it, I’ve moved quite a few mature roses in my lifetime and often in the middle of summer. Some with flowers on them and barely lost a blossom. Here are some tricks I’ve learned.


                          Right in the spot where it’s going ,dig a big hole and make sure you mix 50% compost in with the soil you are going to put back in the hole. How big should the hole be? Start with 2’ x 2’ because you are going to try to keep a large a root ball on the rose you are moving. You want that hole big enough to take the entire rootball.


                          Before you grab the shovel, take your secateurs and clip off any thin, weak or dead growth. Reduce the rose’s size by about one-third. If you have many canes and can take out an old one now is the time. The purpose of this is to reduce the amount of top growth the soon to be smaller root zone will have to support without radically cutting the rose back. As a last step take some twine or rope and tie it around the plant to keep the canes together so they don’t hit you when you are trying to dig up the plant. Don’t be afraid to pull the canes in snug, but don’t break them either!

                          Using your spade, start cutting a circle around the plant by driving the shovel straight into the ground about 1’ away from the center of the plant. This will give you a circle 2’ in diameter. Have something standing by you can wrap around the rootball when it comes up to hold it together. A piece of burlap, old sheet, plastic; it doesn’t matter as long as it will hold the root ball in place while you move the rose.



                          Now go around the plant again, sticking your shovel in the cuts you previously made. Only this time when the shovel is all the way in the ground, rock it back a little to start lifting the rootball out of the hole. You are trying to cut/tear the root ball away from the roots that will be left behind. If you have two people, work on opposite sides of the plant continually going around the circle.

                          When you feel the rootball starting to come loose it’s time to try to slide it out of the hole and on to whatever you are going to wrap around it. Take your time, go slow, use a buddy if you have one, and occasionally slip your shovel under the rootball to feel for/cut roots going straight into the ground. You might even need a pair of loppers to cut them.

                          When you have the rootball sitting on top of your wrap, gather the wrap around the it to hold it in place. Then move it to the new location. Once there gently slide it off the wrap, into the new hole and backfill around the rootball with the 50/50 mix of soil and compost. Lastly, water in very, very well and add mulch to keep the root zone moist and cool.

                          It will take the rose about three to four weeks to regenerate a root ball big enough to support the top growth. To help the rose survive during that period, here are two essential watering tips I’ve learned over the years.

                          First, when you water use drip irrigation or put the hose on a slow stream and leave it for at least thirty minutes. Because the rose now has a smaller rootball it will take longer to drink up the amount of water it needs. Think of it this way. If you need to drink six glasses of water a day, you can drink them quickly if you just gulp them down. However, if you have to drink them through a thin straw it will take longer to get the same amount of water down. That’s what is happening with your rose. The smaller rootball means it is now drinking through a straw. The drip, or slow stream over thirty minutes, gives it the time it needs to soak up enough water.

                          Second, for the first two weeks mist the rose a couple of times of day. If you have a full time job, in the morning and at night is fine. I use a hose with my finger over the end. Don’t soak it - just a brief light misting rain. I came up with this one observing rose cuttings in a misting greenhouse. The idea behind the mist on the new cuttings is to allow them to take in water through their leaves until they develop roots and can take it up from the soil. Same with your newly moved rose. The drip, or slow soaking, is the first part to making sure it gets enough water from the roots and the misting is the second way it will get enough water. Think of it as a backup system!

                          While moving a large rose during summer is not ideal, taking the time to get a good rootball and then following that up with slow watering and misting will greatly increase your chances of success.
                           
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                          • wiseowl

                            wiseowl Friendly Owl ADMIN Staff Member

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                            GROWTHS ON ROSES

                            The roses otherwise appear to be healthy. ... A: The fuzzy growths known as moss galls are caused by a tiny wasp that lays her eggs in the stems of rose bushes in spring. When the larvae hatch and begin feeding, a chemical reaction causes the mossy looking galls to form.

                            74b6f1e8-5b17-11e5-91ef-1b38574a319f-316x316.jpg
                             
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