I overheard a man at Panera the other day telling a friend that since we are a month ahead this season, he was hoping the constellation would be that August would feel like September. I am guessing there are more than a few people who feel the same way. As I water my very well established plants for the third or fourth time in the last month I am starting to wonder whether they are all going to make it. The most affected have been my Astilbe. These water-loving shade plants usually bloom a hot pink around the fourth of July. They’ve been done blooming their stunted shoots weeks ago and their leaves are dried and shriveled.
Above is a better shot than what they look like in my yard this year and to look this good they need consistent moisture. I have already written about watering correctly, but in times of drought there are some last resorts to try when the plants appear to be beyond their breaking point as well as new issues to worry about.
Under normal conditions, plants should not be watered on the leaves. This promotes diseases or can even burn the leaves once the sun heats up the water droplets on the leaf surface. However, in very hot temperatures, the plants will wilt because they lose water faster through the leaves than they can take up by the roots. The natural response would be to water when the plants shows wilting. If the soil is moist or you’ve recently watered first water by misting the tops of the plants and they should bounce back once the temps begin to decrease at night.
Another stress sign for drought affected plants is that they may exhibit pest or disease problems that don’t normally cause an issue. The best example we’ve seen this year is vinca minor. My boss brought it to my attention and I first thought it was just drought stress. This drought tolerant ground cover can be affected by stem blight during cool wet weather. However, this year, it has become an issue the last few weeks, brought on by drought. I was able to discuss this today with Jim Fizzell from James A. Fizzell and Associates, our industries’ plant guru. The stems turn black and pull out easily. The tops of the plants are straw brown. At this point, it is important to not spread the disease by watering too much and leaves should be removed as much as possible to keep the disease from spreading. Fungicides cannot be applied till temperatures are lower.
If a plant gets so wilted that the leaves are crispy, those leaves will probably not survive. However, this doesn’t mean that the plant is dead. If it is early enough in the season the plants may re-leaf. I’ve seen this happen with Arrowwood viburnum commonly. If the stems are still green, they can be saved. If it doesn’t re-leaf in the same season it doesn’t mean that they won’t the following year. The most important thing is to resist the urge to over water. Without the leaves, the plant will not be able to deal with water as well. Continue to water deeply and infrequently to get the best results.
Some commonly drought affected shrubs are Hydrangea, Arrowwood Viburnum, and Privet. Some of the best I’ve seen holding up well are Cotoneaster, Rose, and Autumn Blaze Maple. Others I don’t normally see a problem with, but have this season are Burning Bush and Spirea. Some perennials to watch are Astilbe, Lady’s Mantle, Ferns, and Hostas which are mostly shade plants. Drought tolerant plants are Ornamental grasses, Sedum, yarrow, Vinca. Perennials I have seen dealing with drought stress that normally do well are Coneflower, Sunflower, and Phlox. If the watering regime is kept up, most plants will come through with a few battle scars, but will be better for it in the end.
Coneflowers are blooming now and are beautifully showy from a distance.
One of the easiest groundcovers to grow. These Creeping Sedum can be easily transplanted and fill in well even in the second year.
The best way to water is with soaker hoses since they will get the water to the roots the right way. If something looks unhappy, but not dead, don’t take it out just because of its lack of perfection. A little bit of struggle can help. Many trees and some shrubs will show signs of stress in establishing about two to three years after planting, especially in poor clay soils. I’ve noticed to be a particular issue this year because of the drought. It is better to get them over the third year bump rather than starting them over. I recommend not to deter your planting projects, but water the right way and realize that these plants are here on earth because they’ve survived drought before and will likely do it again.