When plants are suffering in late summer, how do you know they are ok?
This was a question posed to me by a client for whom I did an installation for this spring and am providing follow on maintenance. By mid August, the Amsonia ‘Blue Ice’ that we had planted for him was starting to look a bit ratty after 2 months of high temperatures and alternating between dry and wet conditions. It’s leaves were either dropping or folded tight upwards to the stem.
Truth be told, it’s a question I frequently have this time of year, especially for plants that are new this year. Like a lot of things in life, there’s no simple answer. But there are a few items that you can inspect, which should lead you in the right direction.
Besides just looking at the upper foliage, look at the base of the plant for signs of new growth. In the case of the Amsonia ‘Blue Ice’, it’s new buds all form from a central point at the base of the plant. They most likely won’t put out any growth from those buds this year. But next year, this is where all of the new shoots are going to come from. If you see these and they look somewhat green, you are good. As an experiment in planting during harsh summer conditions, I planted Butterfly Weed (Asclepias tuberosa) in mid July during the peak of summer heat and dry conditions. While 3 have done fine, 1 of the plants is just ugly….yellow leaves and its seed pods are opening early. Even though the top looks poor, when you look at the base of the plant, it has new shoots just poking through the soil. Again, this is a sign that the plant is fine.
Look for new growth in upper areas of the plant. Although the existing foliage might not look good, you might see new growth coming from the main stem. Below, I have a Ruby Dwarf Sweet Joe Pye Weed that I did as part of my summer planting experiment. Some of its leaves, mainly on the stem to the left in the first picture, are yellow with brown on the outside. Since the leaf is dry on the outside, my guess is that I have been underwatering it. That being said, the question is whether it is alive and whether it will make it. When I look at the leaf axils (where the leaf stems attach to the main stem), I see new shoots emerging. Additionally, when I look at the base of the plant, I see 2 new shoots in various stages of emergence. From this, I would conclude that the patient will be fine, but just needs closer observation.
Feel the soil at the base of the plant (in what would be the original potting soil): This is most applicable to plants that are new this year, whose root systems haven’t had a chance to fully stretch into the surrounding soil. Is the soil at the base moist or wet? If so, I would hold off on any more watering. For most plants you want to wait on watering until the top 1” or so of soil has dried out. This helps to prevent the plant’s roots from rotting due to being in waterlogged soil for a prolonged period of time and encourages the plant’s roots to stretch into the native surrounding soil to search out moisture. If it is dry, give it a good deep watering and then wait for the soil to dry out until you water it again. If it has lost all of its leaves, possibly due to going dormant (plant version of hibernation), you want to error on the side of less water as its no longer losing moisture through its leaves and therefore needs less water.
Give the plant’s stem a gentle tug upwards. When you pull up, do you feel resistance or does the plant come out of the ground? If the former, your plant’s roots are still healthy. If the latter, its likely that its dead and it’s root system is no longer healthy and anchoring it into the ground.
When I pull upwards on the Butterfly Weed, I feel resistance / no movement, which indicates that it's root system is still healthy
If in doubt, just let your plants be. Most plants are pretty resilient and will bounce back later this year or next Spring.
