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Discussion in 'Landscape Architecture and Design' started by MowJo, Feb 17, 2001.

  1. MowJo

    MowJo LawnSite Member
    from KY
    Messages: 70

    I maintain a professional technology park and am responsible for total grounds maintenance. The one area I'm having trouble with is the annual color beds (which is NOT the problem to have, everyone notices flowers!)

    Heres the situation:

    There are (9) full sun, poor soil, overhead irrigated, median plantbeds. The irrigation covers both junipers and any flowers. The owners have insisted on the exact same annuals each season (7years total).
    1. Pacifica Red and White Vinca each summer.
    2. Majestic Purple and Yellow Pansys each winter.

    Heres the problem:

    The Vinca crops have been in decline for several seasons. They tend to yellow, often the stems turn black and have low numbers of blooms. I have observed many brown/yellow vinca with tiny new green leaves trying to grow. These problems vary from bed to bed, some beds thrive at one end and are dead at the other. Snapshot herbicide was used as a pre emergant for a couple of seasons (have since heard that was a big no no).

    My Questions:

    1. Could the irrigation be the cause of all of this?
    2. Could soil variations be the source of inconsistency?
    3. I've heard you can't plant Vinca every year do to a "Vinca root fungus"?
    4. Is Snapshot responsible for the declined health?
    5. What is the best resource on the net for these problems?

    Ironically the Pansys do just fine.

    I have suggested that all these factors are possibly responsible and we should experiment with other flowers.

    In short: How do I fix this problem and exceed this customers expectations?

  2. bobbygedd

    bobbygedd LawnSite Fanatic
    from NJ
    Messages: 10,178

    well, i am not an expert, but i do have one customer that i use vinca for, every single year. when i started there 5 years ago, i created the bed with good topsiol, no fert. i have since done absolutly nothing to this area, just in the late fall, pull out the dying vinca, and in april plant new ones, nothing else. i will tell u this though, these flowers get no water, her sprinkler system doesnt reach that far, and the are in full sun, and they do real good every year. BOB
  3. MowJo

    MowJo LawnSite Member
    from KY
    Messages: 70

    thanks for the reply, I tend to agree with you. I have planted some (from the same crop) in places that have NO irrigation and they basically thrived. Watering with the shrubs 2 or 3 times a week is probably the root of the trouble. It may be vital seperate shrub and flower irrigation zones.

    Guys, any more input would be appreciated.
  4. Rodney Johns

    Rodney Johns LawnSite Member
    Messages: 121

    First of all Vinca of any species tend to be a heat loving full sun plant. These plants are very tolerant of full sun and low amounts of moisture. Some of the symtoms you are describing could be as simple as a pythium outbreak. Any time you see blackened stems and falling over at the ground level that is a symtom of pythium. You do have choices.

    1. Convince the people in charge to make a change. As with any crops without rotation of species you can create a situation where fungus problems are at high levels and build up from year to year. Changing plant species will allow more tolerant plants to thrive where others will fail. Try going to geraniums, petunias, Salvia, or something very hardy.

    2. If you can't switch plants switch the environment conditions. Pythium can only grow as with any pathogen under specific conditions. High humidity, moist conditions, and lack of sun all can lead to out breaks of fungus no matter what your fungus problem is. (also junipers tend to secrete toxins to eliminate competition under and around the plants).

    3. Also try improving your soil conditions. Try incorporating large amounts of organic matter into the soil and tilling it into the bads. Peat moss works well as do leaves. Also try putting in a little 5-10-5 fertilizer.

    4. Lastly try chemicals. Often chemicals are very expensive and often cannot solve a problem all by them selves. Too much water will still cause rapid reaccurances of the pathogen. There are numerous systemic controls that will cure a variety of annual plant pathogens in case you have many things killling your plants.

    This is just a start. Without knowing what zone you are in and more specific details I would suggest this as a start. Pythium may not be your fungus. It could be powdery mildew or any number of the slew of pathogens which atack anuals. Although some solid pratices in prevention go a long way for any.
  5. mbwent

    mbwent LawnSite Member
    Messages: 24

    If they insist on same annuals yearly, call your county extension agent to come out and go over the problems with you and then report their findings back to the owners. The county extension services are free and an excellent resource for all types of problems and questions. Look under your co. white pages for phone number, their is an office in each co.
  6. jrodgers

    jrodgers LawnSite Member
    Messages: 229

    If moisture is the problem then cut back(way back)on the irrigation the Junipers wont mind as long as they are established. Vinca is a very unpredictable and picky annual the same thing happens with many of my Vinca plantings.
  7. Lanelle

    Lanelle LawnSite Bronze Member
    Messages: 1,361

    This does sound like too much water. Couple a rainy spell with an automatic irrigation system and Vinca will get too wet, decline and never recover. Seems like your client could possibly save both their water and their flowers with less irrigation time. Once a week would probably be enough.

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