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Sunday, February 16, 2014

Star Jasmine Problems Mostly Soil, Mulch and Cold Related

Q. What can I do to correct all the issues afflicting the star jasmine this winter?


Problems with star jasmine. Most of these are caused by poor soil conditions and winter cold. Perhaps it might be not watered with enough water.
A. The easiest is to not plant it. Hard to say exactly but generally I would call the problems in general, stress. The stress could have come from freezing temperatures, lack of water, poor soil or poor soil amendments such as high salts and lack of organic matter.
Great place to put a star jasmine for aroma and welcome greetings to visitors.
            The plant is some eastern and southern China and which means it is not from a desert and not really a desert plant. We have to adjust everything around it for that reason. It is not going to like desert soils or rock mulch for that reason.
Star jasmine used as groundcover in rock mulch. I guarantee that plant HATES it there. Developed iron chlorosis due to rock mulch and poor soils.
            Soils must have lots of rich soil amendment (compost) and it will really appreciate wood mulches. It does well as a groundcover but I think it is best as a north or east-facing trellised vine. Particularly near a window that can be opened in the Spring.
When star jasmine is growing well and in good health the leaves should be a vibrant green.
            The flowers are very fragrant so it should be planted in locations where the fragrance can be appreciated. It is an old-fashioned plant. Southerners might know it by the name “Confederate jasmine”.
            It handles the cold winters well if it is not in rock mulch. At real low temperatures the leaves may get that bronzy, yellowish color that plant leaves can get when it is cold but will handle temperatures to 10F pretty easily. Citrus leaves will bronze in winter the same way.
            Flood the soil with water to remove possible salts and let it drain. Add compost to the soil surface around it and water it in. Replace rock mulch with wood mulch but keep the mulch away from the stems to prevent collar rot.
            Fertilize in the spring with a good quality fertilizer for flowering plants like roses. Shear off the old growth and let it regrow in good health. One time I had to cut a star jasmine used as a vine way back to get it to flower for me in a north exposure.

3 comments:

  1. One of my star jasmine is in bad stress. It looks like it is dying and I am so sad. I have had it for 30 years and its twin is doing just fine. The leaves are looking like it is lacking water, but I know that isn't the case and it has a lot of dead vines. I would like to know if cutting it back after its flowering season would help the plant to regenerate. These two plants have the most wonderful fragrance and have been the best vines for our front yard. I will be very disappointed if I lose it . Any suggestions

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    1. Kathy. I would think about doing some renewal pruning on the vine. There are two approaches to pruning older shrubs and it also applies to vines as well with a little modification. Here is a link from Penn State University that goes into detail on the process with shrubs. With your vines it is similar and the timing you mentioned...just after flowering season is over...is perfect. At this time you would select the oldest wood from the base of the vine and eliminate cut one or two of the oldest to within a few inches of the ground. Unlike shrubs the problem with cutting vines like this is finding the severed shoots from the tangled vine mess. Just let the foliage on the severed shoot wilt. As soon as that happens you can pull it free from the rest of the vine. The other approach is more radical.... rejuvination pruning. Rejuvination pruning is cutting all the shoots back to near the ground and letting them all regrow. More radical but easier. Both will work but with a different visual impact.

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    2. I forgot to post the link.
      http://extension.psu.edu/plants/green-industry/news/2012/hacking-whacking-dealing-with-overgrown-shrubs

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