Downy Mildew – Can I Plant Impatiens Again?

Downy Mildew – Can I Plant Impatiens Again?

2022 UPDATE:  Yes, this problem is still with us… Some of our customers have planted the regular, six pack impatiens and they have done well. But others have lost what they planted in early June, especially when June has been cool and damp. For the best success with six-pack Impatiens, plant them a bit later in the summer, and don’t water frequently at night or very early in the morning. Being a water mold, damp, cool conditions are most likely to promote downy mildew.

Also, note that the newer variety, Beacon Impatiens, are resistant to downy mildew. They are not available to us in six-packs yet, but they may be in the future. For more information about Beacon Impatiens, click here.

Last summer many of our Cape Cod customers were shocked when the common impatiens they’ve relied on for years seemed to just melt away. This happened in small window boxes and large estate bedding areas and was seen all over the Northeast. It struck plantings on some properties as early as late-June, and others in September. Homeowners and landscapers alike watched what was normally a sea of color turn into a forest of bare, ugly stems.

This is C.L. Fornari’s shot of an Impatiens with Impatiens downy mildew.

The culprit was impatiens downy mildew disease. This is a fungus-like water mold with the scientific name Plasmopara obducens. The spores swim though water so this disease spreads quickly in moist or wet conditions. Spores are also carried by the wind over great distances; this explains why some people saw damage early in the summer while others didn’t lose their plants until fall. Despite having a similar name, this problem isn’t related to powdery mildew.

The question on everyone’s mind, of course, is “Can we safely plant impatiens this summer?” Unfortunately, the answer isn’t clear.

We know that spores of this disease can over-winter in the soil. We don’t know if or how the mild winter will affect this. Also unknown is if future weather conditions will promote or hinder disease problems. Most experts in the field recommend being safe and not planting common bedding impatiens (Impatiens walleriana) where there was a problem in 2011.

Fortunately, New Guinea impatiens and all types of begonias are not affected by downy mildew. Those who want to avoid a recurrence of the problem should plant these or other shade/part shade alternatives.

Is there any control of downy mildew and is it safe to replant this annual this year? If you or your customers want to plant Impatiens walleriana as usual, you can drench the soil with one of the bacterial-based fungicides, and before planting and to spray the same product on weekly, particularly the underside of the foliage. You can also use another fungicide that is labeled for downy mildew. This treatment has been shown to at least slow the disease down in warmer, drier conditions, but if the summer is cool and damp you’re likely to have your plants affected anyway. There is no “silver bullet” cure for Impatiens downy mildew. If you want to be sure to have flowers, plant begonias or other shade-lovers instead.

To read more about this disease, see this tip sheet from Ball Horticulture or in our 2013 Update.


  1. Emily W. on March 14, 2012 at 12:07 am

    I lost at least 100 impatiens walleriana that I’d grown from seed last summer to downy mildew. Just wanted to say that another species of impatiens I grew also succumbed to this disease: impatiens balsamina (Touch-Me-Not).
    I am planning on growing and planting only New Guinea impatiens this year.

    • admin on March 15, 2012 at 5:17 pm

      I know that it doesn’t help, but you weren’t alone! How frustrating it was for many of us to see those plants turn into bare stems.

  2. John Welsh on July 31, 2012 at 3:59 pm

    Sadly, downy mildew is back. I’ve lost my entire planting of both single and double impatiens to the disease. Never had it before, and originally thought the plants were suffering from lack of nourishment, even though they were planted in good, rich soil, and with a fertilizer boost when first put into the ground. From what I’ve read, replanting the area with impatiens next year or for several years later is a no-no because of the persistence of the disease. It occurs to me that it might be a good idea to get rid of the mulch too and start fresh, pathogens being what they are.

    • CLFornari on July 31, 2012 at 4:25 pm

      John – so sorry that you have downy mildew on your impatiens. We agree that you shouldn’t plant regular impatiens in this location for a few years. New Guinea Impatiens don’t seem to be vulnerable to this disease and begonias are also an option for a substitute. We doubt that removing the mulch will prevent further infections but we leave that up to you.

  3. john beach on August 18, 2012 at 5:30 pm

    I just lost an entire 15*3 ft bed of impatients to, I assume, this disease. The strangest thing is that this disease not only killed my plants but consumed them too. Aside from a couple of splindly stalks at the far end of the bed, the entire bed of plants has vanished! I have 2 other beds on the property, but they are OK. I guess that I won’t be planting impatients in this bed any time soom. I might add that this winter was the mildest in my memory and that may have contributed to the problem.

    • CLFornari on August 18, 2012 at 5:38 pm

      So sorry that you lost your Impatiens too. You’ve described just how this disease looks – it often seems as if the plants have just melted away, although sometimes a tiny forest of bare stems remains. It isn’t just Cape Cod that has had the problem…there have been outbreaks all over the country. Our advice is to plant something else such as begonias next year.

  4. Dee on August 20, 2012 at 8:57 am

    I just pulled out 12 flats of impatiens due to this disease. It literally turns my stomach to see my mounds and mounds of color turn to plain stems. No other flower presents as beautifully as these. Is it true that I can’t ever have these again? Or will there be some “cure” to this disease in the future?

    • CLFornari on August 20, 2012 at 9:57 am

      Dee –
      We feel the same way! There is nothing like Impatiens walleriana for easy, inexpensive, season long color! Unfortunately it looks like you won’t be able to plant these for several years to come. What we know is that in areas of Europe that have had this disease they weren’t able to plant them again for many years. It seems, however, that the spores are killed if the winter temperatures drop below 5 degrees for any length of time, so if we have a very cold winter it’s possible that it might go away. No one knows for sure, however. The new Sunpatiens are resistant (I am growing them myself this year with no problem, even though I had the disease on my property last year.) as are New Guinea Impatiens, all begonias and coleus.

  5. fran on August 25, 2012 at 7:46 pm

    I purchased 12 full flats of impatiens, the same as every prior year. Every plant became spindly and lost their leaves. I thought it was due to a very hot May and June. I am glad that it is not just my garden. I will plant begonias for the next few years. This mess cost me over 250.00!

    • CLFornari on August 25, 2012 at 8:26 pm

      You aren’t alone – all around the Cape we see a forest of Impatiens stems! I was recently at Willowbend where they forbid anyone to plant Impatiens this year since they had the downy mildew problem last year. They used pink wax begonias instead and I have to say that it was beautiful. We’re thankful that there are so many great alternatives.

  6. filly brown on September 6, 2012 at 2:39 pm

    I am so glad to have come across your website. I had this problem last year, but I had no idea what it was. I just thought it was a bad batch of plants.
    So I planted impatience again this year. Sadly they are all destroyed. At least I know now what it is, and I will not plant them again next year to try to stop the spread of the spores.

    filly brown

  7. Browns Fan on September 8, 2012 at 5:11 pm

    Our whole neighborhood has this problem this year…first time in Cleveland area…

    • CLFornari on September 8, 2012 at 5:23 pm

      Our sympathies to all who have this disease. We’re recommending begonias, New Guinea Impatiens and Sunpatiens to all our customers for at least the next few years. We’ll keep everyone posted with updates.

  8. Fran Hoginski on September 19, 2012 at 12:02 pm

    Last week I gave in-dug up 300 plants-have never seen this before- have been planting impatiens for over 40 yr– 6 hanging plants are next to go! thank you for all the suggestions!!

    • CLFornari on September 19, 2012 at 5:02 pm

      I know, Fran – it’s heartbreaking that we may not be able to plant this normally foolproof annual for many more years. Fortunately the New Guinea Impatiens just keep getting better and better, and the Begonia selection continues to grow!

  9. renita jackson on February 27, 2013 at 11:08 pm

    Can I Still use the soil my Impatiens were planted in when they got downy mildew. I will plant begonias

    • CLFornari on February 28, 2013 at 8:14 am

      You can use the same soil since Begonias aren’t susceptible to this downy mildew. If you’re planting in a container, however, you might want to “refresh” the soil by adding a few scoops of compost and a small handful of an organic fertilizer. Happy Spring!

  10. Dirty Gertie's Gardening on May 1, 2013 at 6:36 am

    I do gardening for a small handfull of clients and a few of them use impatiens in large drifts. For the rest of my clients I can substitute New Guinea or Begonias in their “impatiens” areas. However for my clients that use a tons of them there is a huge difference in cost between a 6 pack of regular impatiens and the larger pot that New Guineas are sold in. For some of my clients the difference in price is too much.

    So I have a few questions:

    Why aren’t New Guineas sold smaller in a 6 pack?

    Is there something else that is less expensive that will work in shade? (I like a Coleus but most of my clients want “flowers”)

    Are they hard at work trying to insert a gene from lets say a New Guinea impatiens that makes them resistant to the mold into a Walleriana? A spray would be ok but again, for large drift plantings at some of the estates I work at or for commercial drift plantings spraying isn’t a very good option.

    Thanks Country Gardens I’ve had a partnership with you for many years… you’re the best!

    • CLFornari on May 1, 2013 at 11:08 am

      All great questions, “Dirty Gertie.”
      New Guineas are sometimes sold in six packs but they aren’t the same plants as those sold in pots. Usually when an annual is only sold in pots it’s because it’s propagated by cuttings only. Some plants are either easier to grow from cuttings or only possible to grow from cuttings. Also, when a plant is propagated by cuttings you know that it’s going to always be the same plant…seed grown plants can vary. (If you’ve ever grown Cosmos you’ve probably had the experience of some blooming well and others just making a tower of green foliage with few flowers – this is because they are grown from seed and can vary greatly in growth and habit, even when you buy a named variety.)

      The New Guineas that we will have in six packs will still be more expensive than the Impatiens or Begonias in six packs. Also, know that the New Guineas sold in six packs are seed propagated and not the same plant as those sold in pots. They tend to not be as wide or have as many flowers. Be sure that you plant all New Guineas with a combination of time-release fertilizer and an organic fertilizer for feeding all summer – we often use a 50-50 combination of Osmocote and Flower-tone.

      Begonias are your best alternative. The “Whopper” begonias get large and so cover a great deal of space. Last year in Willowbend the landscapers used all greenleaf wax begonias with either pink, white or red flowers and the result was stunning – again, they were well fertilized.

      Yes, the breeders such as Ball Horticultural are working like crazy to develop a seed grown Impatiens walleriana that is resistant to downy mildew. All of America is cheering them on!

      Agreed that although spraying weekly can slow this disease down, the cost of doing so in both time and product makes the plantings much more expensive…for that same money you could get all New Guineas or all Whopper Begonias. Not only that but spray can only hold off the infection for so long…in cool and damp conditions the plants are likely to get it anyway.

      Thanks for being a regular customer…we’re happy when you’re happy.

  11. Sherry on May 1, 2013 at 1:53 pm

    I am the gardener for a major university in Wisconsin. I have planted a large bed with Impatiens for many years. Last year I watched my beautiful bed crash and many blaming thoughts went thru my head. I finally figured it was some kind of disease and planned to plant a different shade flower this year. Now I know for certain what the problem was–thanks to Country Garden!

    • CLFornari on May 1, 2013 at 3:48 pm

      Hi, Sherry! Glad we could help. This disease was seen nationwide last year. Horrible, but there are many alternatives and while the plant breeders come up with something that’s resistant it gives us a chance to try new things.

  12. Dirty Gertie's Gardening on May 9, 2013 at 8:01 am

    Thanks so much for the information CL! I’ve been planning what to use for my clients that use drifts of impatiens and I’m going to take your advice and go with the Begonias. In a few individual spots (not large drift plantings) I’m going to try and some Coleus and Lobelia. I used lobelia in an under tree planting at an office in Osterville last year and although I was told it would not bloom all season, it did. It was in fairly deep shade with a irrigation system and it looked great.

    We are going to miss our impatiens and I hope Ball Horticultural is successful in producing downy mildew resistant Impatiens. In the meantime we’ll be stepping out of the box to try new things. See you soon Country Gardens!

  13. Kathy on August 11, 2013 at 5:55 pm

    I looked at all of the impatience that I planted and they are dying and at first I thought, too much rain that we have had here in Notheast Ohio, but this is the second year in a row that this has happened; I plant impatience because they are beautiful and we have a lot of shade. I thought I would take a look online and found this website and found that it must be the downy mildew, I have never had this problem, my New Guinea impaients look great. I think I will be planting them next year instead of the impatience. Happy I found this website!

    • CLFornari on August 11, 2013 at 7:21 pm

      I’m glad that this was helpful. If you ever come out to Cape Cod be sure to stop into our garden center and say hello.

  14. Gary Bumgarner on September 17, 2013 at 12:35 am

    I Googled “New Guinea Impatiens melting” and found your website. My Bavarian Chalet is surrounded by 175 feet of flower boxes and I have planted the shady sides with N. G. Impatiens, common impatiens, and wax begonias. They all melted away and died except for those that get a decent dose of morning sun, where they thrive beautifully. What other colorful plantings can I make in Eastern Washington that this disease won’t affect?

    • CLFornari on September 17, 2013 at 7:53 am

      Your begonias and New Guinea impatiens shouldn’t have melted if you have Impatiens downy mildew – it only affects the common impatiens. If the other plants also died I’d suspect over watering…all three of these annuals will succumb to crown rot if the surface of the soil is kept constantly wet, especially if you have cool nights. If the beds are being watered frequently the areas in morning sun might be drying off better so you’d see successful plantings there. If you think this is the case, water deeply less often so that the surface of the soil is allowed to dry in between soakings but the roots are kept moist.

      If your plantings are in deep shade all varieties of impatiens won’t flower well. Even the wax begonias flower better when they get at least three hours of direct sun. For deep shade you’ll be better off planting perennials such as hosta and ferns and using colorful pots, a colorful bench, brightly painted posts topped with bird houses or other man-made objects to brighten the area.

      I hope this helps!

  15. Vicki Bargar on June 10, 2015 at 1:12 pm

    Are the spores for Downy Mildew air born? Will they affect my pots or hanging baskets that have all new soil?

    • CLFornari on June 10, 2015 at 1:38 pm

      Yes, they are airborne. This is a water mold and effects plants in cool, damp conditions. So watering your pots and baskets in the AM, not in the evening or at night, might help. No knowing, unfortunately.

  16. Robbi Hennigan on June 2, 2016 at 5:29 pm

    Hi CL,

    Robbi and Matt here. =)

    Any news on the status of Downy Mildew and resistant Impatiens or fungicide?

    Hope you’re well!!!??

    • CLFornari on June 2, 2016 at 8:53 pm

      Robbi! Great to hear from you and hugs to you and Matt – I hope that you, the business, and family are all well. The only Impatiens that are resistant are New Guniea Impatiens and Sunpatiens. The DM is still around, but it’s a water mold that is active in cool, damp weather. So planting regular Impatiens too early in cool damp conditions (like right now!) makes it likely, as does frequent early AM irrigation and fall cold damp weather.

      Last year some people lost their impatiens early, some mid-summer, and some in the fall. Others found that their plants did fine all summer and most of the fall. So bottom line is we can’t say one way or the other that it’s OK or not OK to plant!

      There are fungicides labeled for Downy Mildew, including the one we sell at HCG called Agri-Fos. It needs to be used regularly according to directions, and people have found that when applied frequently over the summer it does keep the problem at bay longer.

  17. Robbi Hennigan on June 3, 2016 at 7:43 pm

    Grazie, Grazie CL! You’re the best! I’ve been talking to my Lower Cape resources and no one mentioned planting too early could be a problem. Thank you for the tip!

    We have 17 window boxes and planters and have replaced the impatiensthe last few years with New Guinea and Tuberous Begonias and other trailing flowers, after three years ago loosing all at the end of the season. So pricey! I’ve been anxious to go back to impatiens for their faithful flowering and six pack prices.

    Today, I purchased a mix of the above and impatiens, but have cleaned my window boxes with a bleach mixture. I’m hoping to plant in these boxes tomorrow. Will purchase Agri-Fos!!!!

    Wish me luck! Signed, Worried Flower Mother, Robbi

    P.S. Matt is GREAT and so are the kids! PTL!! Hope your boys are too!!!

    • CLFornari on June 3, 2016 at 7:51 pm

      Send photos of how they look, OK? And let us know if the Impatiens last all summer.

  18. Robbi Hennigan on June 4, 2016 at 8:20 pm

    Will do C.L., I’ll send you photos as soon as the window boxes catch on and are blooming. If trouble appears, I’ll update, though I don’t see an attachment option here.

    Spent from 10:00 to 7:30 planting today. We were way behind because of travel. Life feels normal now that we’ve got our home ready for the outdoor living.

    Thanks C.L.!!

    • CLFornari on June 5, 2016 at 4:43 pm

      You can always update with another comment here…I can change your original comment or add to it from this end if you want.

  19. Robbi on September 14, 2016 at 9:29 am

    Hi CL,

    Robbi here again. If like to update with photos, but, don’t see where I can attach here. Advice?

  20. Robbi on September 14, 2016 at 9:30 am

    Oops! I’d like to update. Finger typo from phone!!

  21. Billie Taylor on June 30, 2017 at 11:41 am

    My eldest daughter loves the common impatiens and has had them for years in a planting bed about 2′ by 15′ between the carport and sidewalk. The last 3 years we planted them, they just faded away. She said she saw little webs. That sounds like spider mites to me, but I never saw evidence of them. In case the soil is contaminated with this mildew, I bought her sun-patiens to try this year. If we cover the soil with black plastic, will solarization kill the fungus? The only other cure I know of is to remove all the soil and replace with new. That would be an expensive and back-breaking chore. I have tried to talk her into using the wax begonias which do well in our area (zone 7b), but she doesn’t like them. At one time, this bed was filled with hostas, but a vole got all except the ones at the top end (planted in mostly clay soil). We have voles which have destroyed even young trees in our woodland yards. I plant everything in a cage made of window screen mesh now. I really enjoy your writings.

    • CLFornari on June 30, 2017 at 12:40 pm

      My guess is that you had downy mildew and that the webs were there but not the cause of the decline. Often the lower leaves of the impatiens disappear leaving bare stalks with a tuft of foliage at the top – sometimes people think they were eaten. Since the fungus is both airborne and soil born no solarization will kill it and replacing the soil is a waste of time. There are fungicides that are labeled for downy mildew that suppress it, but you have to spray weekly from planting on, which isn’t really an option for most people both time and cost-wise. Know that downy mildew is active in damp, cool weather so often delaying planting until later in June, and then avoiding frequent watering and all watering at night (in other words water every four to five days in the morning) will mean that you have them at least until the cool, damp fall weather arrives. There are zillions of other begonias including the “Bonfire” series that grow huge and are colorful, and you can also use New Guinea Impatiens if you have at least 3 hours of direct sun. You could try perennial Japanese Painted Fern, and Hakon grass ‘Aureola’ if you live in a zone 6 or higher.

  22. Hannah on August 6, 2022 at 9:40 pm

    I had downy mildew last year, but a first thought maybe my impatiens were getting too much sun as it was getting closer to fall and the tree they were planted under was losing some leaves. Fast forward to this year. I planted Sunpatiens in the same spot and they have done pretty well until now. I am sure that my SUNPATIENS have downy mildew. I have never heard of this and didn’t know that it was possible.

    • CLFornari on August 8, 2022 at 11:21 am

      In general Sunpatiens are resistant to Impatiens Downy Mildew. It could be that your plants are failing for another reason, but without laying eyeballs on the plant it’s impossible to know. If you’re on Cape Cod, bring in a sample for us to look at.

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