Doomsday for Impatiens?

//Doomsday for Impatiens?

Doomsday for Impatiens?

Are your impatiens looking terrible this year – maybe even dying? A new disease, first identified in 2004, has been spreading rapidly across the United States and other countries and has now landed in Southern California. The disease is called Downy Mildew, or among scientists Plasmopara obduscens.

The disease is causing at least a mild panic among many home gardeners and professional landscapers. But before serious panic sets in, it is important to know that Downey Mildew only effects old-fashioned, regular impatiens. It has no effect on New Guinea impatiens or any other plant in the garden.

The disease is a pathogen, similar to a fungus, and it is deadly. Even worse, it is extremely difficult to diagnose and there is no effective treatment once it shows up in your garden.

Downey Mildew ravaged most portions of the East coast and Midwest last summer. Nurseries there were receiving reports of plants defoliating and then dyeing. At first, the culprits were thought to be poor watering habits, snails and slugs or even fertilizer burn. But soon, it was clear that Downey Mildew was the cause. This year, most garden centers in these areas have already discontinued the plant. The garden centers that continued to sell impatiens are doing so with a “plant at your own risk” approach. In Europe, where the disease got an earlier start, impatiens have been essentially eliminated impatiens as an option. Virtually no impatiens were planted in Europe this year. The U.S. may be headed for the same destiny.

Downy-Mildew-img1

In Southern California a few widely scattered reports came in last summer, but nothing too serious and local researchers and garden centers were hopeful that the disease would not proliferate in our dry Mediterranean climate. We were wrong. During the past 30 days, reports have been flying in of dyeing plants. The plants look fine one day and then suddenly, often in only a few days, defoliate. Just bare stems are left. A few days later and the entire plant is withered and collapsed.

Downy-Mildew-img2Disneyland just announced that it has dropped impatiens from all of its facilities. The Biltmore Hotel, famous for its huge displays of pink and white

impatiens has also dropped the plant.

New Guinea impatiens and their hybrids are not affected by the disease. 

Downy Mildew isn’t exactly a fungus, it is a water mold, but for the home gardener that’s a subtle distinction. It spreads from plant to plant in either of two methods; through water that stays on the foliage for a period of time or by spores that float through the air. Once it shows up, which we think is inevitable, there’s not much you can do about stopping it.

As the leading garden center in Southern California, on July 5th Roger’s Gardens made a difficult decision. We stopped selling regular impatiens, both in our store and in our landscape division, and removed them from our sales tables. We even removed impatiens from our planted baskets and bowls. It was a painful decision, but it was the responsible thing to do. Roger’s Gardens also announced that they would replace or refund any customer who has plants infected with the disease. 

So far as we know, we are the first garden center in the area to notify homeowners and gardeners of the problem and to discontinue the plant. Impatiens are the number one selling plant at Roger’s Gardens as well as most other garden retailers. But rather than sell or promote a plant that will likely fail, Roger’s Gardens has chosen to offer better alternatives. I am proud of Roger’s Gardens for putting its customer’s success ahead of a short-term business interest. We hope other retailers and landscape companies will follow our lead.

Roger’s Gardens has discovered that nearly every wholesale impatiens grower in Southern California is infected with the disease. In fact, infected impatiens have been shipped and sold throughout Southern California, and probably continue to be. Buyer Beware!

So what should you do? That’s a very easy question. First, fly the white flag. Rather than roll the dice and take your chances; stop planting regular impatiens. It’s a bad gamble. If you already have impatiens in the garden we’re not recommending that you remove them; enjoy them while you can, but be prepared for problems.

Secondly, plant an alternative. Remember, other plants are not affected by this disease. Perhaps the most popular solution would be to switch to any of the New Guinea types of impatiens, including the popular series called ‘Fanfare’, Sun Harmony’ or ‘SunPatiens’. These will provide the closest appearance to a regular impatiens. In fact, these types of impatiens will even tolerate more direct sunlight than regular impatiens and have larger flowers and more handsome foliage. Lots of other choices abound as well, especially bedding begonias, which have been around for ages and are nearly as popular as impatiens. For the more adventuresome, other seasonal alternatives are coleus, campanula, mimulus, hypoestes, bacopa, dwarf fuchsias, torenia, cyclamen, cineraria, lobelia and several others.

newguinea_img1

Impatiens have had a good run, but it’s time to move on.

By Ron Vanderhoff, Roger’s Gardens |  July 18, 2013
 
By | 2013-07-18T15:35:43+00:00 July 18th, 2013|Gardening|6 Comments

About the Author:

6 Comments

  1. Rita Jelsma August 9, 2013 at 8:22 pm - Reply

    I have beautiful impatiens which are, thankfully, not infected with this dilemma…and hopefully, will not be. However, I have a New Guinea impatiens that is not doing well. It is losing its leaves. I am checking my watering habit, etc., and it is still “behaving” abnormally. Thank you for the information…I had no idea. Rita

  2. Ron Vanderhoff August 10, 2013 at 12:24 am - Reply

    Rita, glad to hear that there are no disease issues yet on yours. Hang on as long as you can – but have a “Plan B” ready if and when they succumb.
    New Guinea impatiens are definitely not affected, so downy mildew isn’t the culprit. Without seeing the plant and its environment I’m afraid I would not be much help trying to diagnose what is happening to this plant. If you’re in the area it would be best to bring it back in to us so we can give a better diagnosis.

    Ron

  3. Kathy Stockford August 12, 2013 at 12:00 am - Reply

    For the last 13 years impatiens have been my “go to” bedding plant for my shady garden. They never failed… Until this year. Thanks to your knowledgable and frank article I have diagnosed the problem…. I live up in Vancouver , Canada. I bought my impatiens from Home Depot here in town. I’m wondering if their supplier is from Southern California. I guess next year I’ll be planting New Guineas.

    PS should I contact Home Depot to let them know the fungus has arrived in Western Canada?

    Kathy

  4. Ron Vanderhoff August 13, 2013 at 9:30 pm - Reply

    Kathy,

    I’m sad to hear that your impatiens have contacted the disease – but I am glad that you at least know know exactly what the issue is.

    No, there is no chance that your Vancouver garden centers are getting shipments from Southern California suppliers – the frieght costs and shipping stress would rule that out. They are getting their plants from local growers. However, the disease is essentially nation-wide, so it doesn’t really matter where the plants are arriving from.

    I don’t want to sound pessimistic Kathy, but there is little chance that Home Depot is going to change their policy on impatiens, even if they are fully aware of the disease. There is just too much money at stake for them to walk away. I wish it were not so, because gardeners deserve better, but . . .

  5. James May 14, 2017 at 8:29 am - Reply

    Hi Ron,

    I was aware of this issue and recall that the recommendation was not to plant impatient for 2-3 years. I think this article was originally posted in 2013. Are we out of the woods yet or does the Downey mildew blight continue?

    Thank you,

    James

    • Roger's Gardens May 16, 2017 at 9:11 am - Reply

      Hi James,

      Great question. We are now a few years further into understanding this disease and its impact on gardening with impatiens. We are still learning, but at least know a little more than we did then. My take and what I am hearing from researchers and gardeners is that the disease is still very present in our region, and probably will be indefinitely. However, the severity of the impacts to impatiens varies depending upon the weather. Hot and humid springs and summers are more likely to stimulate the disease that cool and dry springs and summers. Of course, the past three or four years have favored hot-and-humid. What will this late spring and summer will bring of a mystery.

      I have witnessed many, but not all, impatiens plantings over the past few years become completely infected and die very quickly. I have also seen a few that have escaped without damage. However, I am still very convinced that the former is more common than the latter.

      To answer the “don’t plant for 3-4 years” question, this applies specifically to replanting in the same location. If you were to replant impatiens in an area where they were planted prior and damaged by this disease they would almost certainly be killed again, if it was in the 3-4 year period. At least that is what the research is saying. But if it was a new planting in a new area, without any prior disease, then this rule would not apply.

      I know this isn’t a very definitive answer, but I hope it sheds a little light on your question.

      Ron

Leave A Comment