Grapevine leaves with dying areas

[Val-the-Brew-Gal]

I am growing just a few grapevines in my yard. A couple of my vines were growing nicely this early summer with huge beautiful leaves. Within the last 5 days or so, the leaves are starting to thicken, curl and get dead, dried up areas. We are having an unprecedented heatwave right now... multiple days in a row of above 100°. They are in a bed that I have covered with large rocks, which they absolutely loved last year. So are my plants experiencing sunburn and heat stress or do I have another problem?

 

[Wineisgud]

I notice some water pooled under the plant. How often are you watering? Just started some vines myself this year. I rarely watered my young plants and if I do I do it deep and infrequent and only at night or early morning so the water doesn’t heat up from the hot soil and cook the young plants roots. The rocks I’ve heard can reflect too much heat to the vine. This is probably nothing to worry about if you have mostly morning sun exposure. But all day sun may be an issue. That said, they do help retain soil moisture longer which could be okay but only if you follow the deep and infrequent schedule. These plants want to dig deep in search of water to build large root systems. I’d say lay off the water. Even in this heat. And see how it does. Good luck!

 

[balatonwine]

Looks like heat wilt and heat damage. Even with well watered plants, the leaves can wilt in extreme heat. More watering will not help much. The edges of the leaves also seem to be burned by the heat reflected off the rocks. Rocks look pretty, but they can really radiate heat on a hot day with the sun pounding down. I suggest laying something over the rocks to mitigate the absorbed and reflected heat till your temps get lower. If you want to keep the rock look the rest of the year, recommend an easily removable cover such as burlap bags or white cloth.

 

[Val-the-Brew-Gal]

I notice some water pooled under the plant. How often are you watering? Just started some vines myself this year. I rarely watered my young plants and if I do I do it deep and infrequent and only at night or early morning so the water doesn’t heat up from the hot soil and cook the young plants roots. The rocks I’ve heard can reflect too much heat to the vine. This is probably nothing to worry about if you have mostly morning sun exposure. But all day sun may be an issue. That said, they do help retain soil moisture longer which could be okay but only if you follow the deep and infrequent schedule. These plants want to dig deep in search of water to build large root systems. I’d say lay off the water. Even in this heat. And see how it does. Good luck!

I had just watered them and my soil isn't great so it just hadn't sunk in yet. I was worried that with the 110° temp, they would need lots of water but I will definitely take your advice. Thank you!

 

[Val-the-Brew-Gal]

Looks like heat wilt and heat damage. Even with well watered plants, the leaves can wilt in extreme heat. More watering will not help much. The edges of the leaves also seem to be burned by the heat reflected off the rocks. Rocks look pretty, but they can really radiate heat on a hot day with the sun pounding down. I suggest laying something over the rocks to mitigate the absorbed and reflected heat till your temps get lower. If you want to keep the rock look the rest of the year, recommend an easily removable cover such as burlap bags or white cloth.

Yeah, they did so awesome with the rocks last year so I hadn't consider how detrimental it would be with temps above 100° for an extended period. We've never dealt with temps like this before! Anyway, thank you for your observations and tips!