I have been following the heat wave blanketing the US from temps in Philadelphia of 102°, to Newark at 108°, to Baltimore of 106°. When you know people in these areas, it becomes a little more personal. Compared to elsewhere, the weather seems less oppressive, but when you feel the effects, it does not matter where you are.
The highest recorded temperature was in Libya in 1922 of 138°; Death Valley in 1913 of 134°; 129° in Israel in 1942; and the highest average temperature is in Ethiopia at 94°. I wonder if these records will be beaten this year somewhere in the world.
A heat wave with oppressive temperatures and stifling humidity lingered in the Central part of our country, but has pushed eastward. What makes this particularly damaging is that many of the areas under its umbrella are not used to prolonged high temperatures and humidity like here in Niagara Falls. We are currently 85° today, and you can still only be outside for about 20 minutes before you are dripping with sweat. The experts are considering our area a place to go to cool off. With relative humidity of 66%, I personally don’t think so. We have not had rain for quite some time in the city and it is no fun outside.
Lawns are brown and perennials are drying back. And we will be back in the mid nineties by Friday. They call this 85° weather a cold front as severe storms race across the Great Lakes. But will Niagara be in its path? Heavens knows, we need the rain, but a 40% prediction?
This morning, I cut the flowers off many plants to lessen the need for the plants to maintain the foliage and blooms. I trimmed some back so as to have less foliage to support and topple if the storm hits us. Yesterday with temps of 94°, I moved all the potted plants into full shade. It was remarkable how they recovered in only one day’s time.
What is ironic, is even when soil is kept moist (recommended), when temperatures reach 86°, photosynthesis in many plants pretty much shut down and, in some, cell proteins start to be damaged. Water intake also decreases even though it is available to the plants. Plants simply are unable to take up enough water from their roots to replace the moisture lost from transpiration in leaves and flowers on hot days.
When it gets really hot, plants rely on reserves of stored energy because there is little active photosynthetic activity. Pretty remarkable when you consider that they cannot get up and move to a cooler environment. But, under drought duress, they are more prone to disease, unfortunately.
Plants experience leaf scorch, bud drop, excessive wilting, and eventual death in prolonged periods of high heat.
Long, intense sunlight is a real detriment to tender leaves and thin-skinned fruit. The interior of fruit, like tomatoes and peppers, heat up on the sunny side to a larger degree than on the shady side of the fruit. The sun side of the fruit will blister, then get papery gray as the tomato ripens. But nature generally provides a good leaf cover, but as a gardener, I help it along. I let the bolting lettuce shade the tomatoes. I try to remember to keep even watering too.
Some of my plants were well positioned for the heat. The hydrangea above will be in a year’s time with its skirt of coreopsis and canopy of lilac, but the miniature hydrangea below weathers out the heat by being planted tightly in a bed surrounded by boxwood. Boxwood has an extensive root system and can weather dry spells quite well, so it provides shade for other plants in the garden, similar to my bolting lettuce above. The two hydrangea photos were taken at the same time of day, one looking much fresher than the other.
Coleus that is not heat wilted and Phlox which has less powdery mildew than last week. Definitely a head scratcher. If we could only figure out why some and not others….. both have mainly shaded locations, but do get hit by the sun. Makes me wonder why…