Thursday, July 5, 2007

Sun Struck

This plaque on my patio wall is supposed to be a reminder that it could be worse, but it's not working. It's hot as hell! As we go into our tenth day of temperatures 110˚ or higher in Phoenix, we will tie a 1989 record. If we do it again on Friday as forecast, this string of scorching days will stand alone as the third longest of all time. Some record to beat! Such heat is debilitating, even in the shade. It sucks the life out of you, and it even affects cacti and succulents that normally take full sun in Phoenix.

Even they can't take the prolonged sun intensity and are showing signs of sunburn. I noticed today that the Golden Barrel (Echinocactus grusonii) on the left is showing signs of sunburn along the top portion of the ribs that face west. The Echinocactus genus, with proper acclimation, does well in Phoenix in full sun, so this sunburn is a surprise, especially since the south facing portion is ok. Since the tissue is still yellow, there’s a chance it will recover once the weather cools. If the tissue turns white, it signals permanent damage, and that tissue will never recover.

Although the Thorncrest Century Plant (Agave lophantha) on the right has some light afternoon shade, it is also showing a lot of sunburn, especially on the west side. I usually place 30 percent shade cloth over several Agave specimens in my garden, but I don’t bother with the two A. lophantha specimens. They have a thorn configuration that makes it impossible to remove the shade cloth once it catches on their thorns.

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