Is it GONE Yet? Can I Plant Impatiens Again?
Is it GONE Yet? Can I Plant Impatiens Again?
It’s a good question, and one that has passed the lips of many of our customers. So before we get to the long explanation, let’s cut to the answer: We don’t know yet.
Last year there were people on the Cape who planted the regular Impatiens and had them do well into the fall. A few had them succumb to the disease early on and still others (myself included) had them live until early September and then become defoliated by Impatiens downy mildew. Clearly the disease is still in the area.
IDM is a water mold that is active in cool, damp conditions. So we know that when planted in such situations the plants are more likely to die. So why did some people get away with planting them last season? One reason could be that there have been much fewer Impatiens walleriana planted for the past three years, so there wasn’t the opportunity for the disease to hop easily from yard to yard, and planting to planting. In my understanding we still know little about this disease. We don’t know how cold winters affect it, or how long spores stay alive if there aren’t Impatiens to live on. What we do know is that the disease is still around, and if the conditions are right (cool and damp) your plants might get it again this year.
What can you do to help? At the very least, water your plants a bit later in the morning, not at the crack of dawn in the coolest part of the day. Water deeply less often, which is good advice for all your plants, not just Impatiens! Signs of IDM:
- First the leaves look light yellow or stippled.
- Next the leaf edges curl downward or look wilted.
- Fluffy white growth occurs on the underside of leaves.
- The flowers drop off, then the leaves fall away leaving bare green stems. Finally the stems fall flat on the ground.
- Plants that have been infected young are stunted and have small leaves.
UPDATE: 2023. Although planting regular impatiens on Cape Cod is still risky, there is a new, downy mildew resistant variety called Beacon. Read about them here. Ask for them by name.
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My Koosa Dogwood – about 10 years old, and doing well, hardly bloomed this year…. There are a few blooms at the top of the tree – off to one side, but that’s it… The tree looks healthy enough with green leaves throughout, but hardly any flowers.
Why wouldn’t the whole tree bloom? Was it the harsh winter? winter moths that attacked the buds?
Not sure what to do to make it bloom next year…
It might be all of the things you suggested and two more. Often what we see going on with plants doesn’t have just one cause (or one quick fix) but is the result of several factors. So your Kousa flowers might have been zapped by the winter, and eaten by the winter moth larvae. Also, last summer and fall were very, very dry and some plants won’t set good flower buds after a dry season. Finally, Kousa dogwoods are known for a “one year on, a year or two off” blooming pattern. One year a tree will be absolutely spectacular and the next year? Not so much. This is normal. What you can do for your tree to help its overall health is to spread a layer of compost or composted manure around the base under the dripline if this is possible. Then water the tree deeply once a week. Don’t depend on automatic systems that are only coming on for fifteen or twenty minutes to be watering trees – that type if shallow watering doesn’t go down deeply enough to do most plants much good in dry weather.
Another reason for the dogwood only blooming at the top is that it might be overshadowed( in the shade of too many tree(s)
Only the part exposed to the sunlight has bloomed. The other trees shading it have filled in over the years.
Good point, Ann! And so true. Sometimes we assume the light in our gardens remains the same only to see, when we look closely, that it’s grown shadier. That happened to me in my gardens in Osterville.
It was recommended to me to apply copper dust fungicide into the soil a week or so before planting impatient. will give it a try
We advise against this. 1. Copper isn’t really effective for DM. Read this article: http://msue.anr.msu.edu/news/ask_the_plant_pathologist_about_impatiens_downy_mildew_part_iii_landscaping
2. Copper builds up in the soil and so should not be used unless absolutely necessary.
3. Downy mildew is also air-born, so no soil treatment is really effective.
4. Copper is toxic to aquatic life, so again, should only be used when it is necessary and will be effective.