Xtremehorticulture

Texas Olive Froze at 25F or More

Q. I have a Texas olive tree that may or may not have survived this past winter. We have had the tree for several years now and it has always bloomed and grown. I don’t have any new leaves or blooms except the suckers on the bottom.  All our other trees like our sumac, Palo verde, and fruit trees are doing fine.  But not this one. Is there anything I can do at this point beyond just watching it? Texas Olive, Cordia boisieiri, hardy during the winter to about 25F, about the same winter temperature as Myers Lemon. A. That particular tree, Cordia boisieri, is native to the desert southwest Chihuahuan desert and survives to a winter temperature of about 25F; around the same winter temperature as Myers lemon. Because it’s from our desert southwest it is considered xeric in its water use. Lots of good that does you if it is winter killed or severely damaged.  A better choice might be Littleleaf cordia, a smaller tree and found growing on East Flamingo in Las Vegas. A better choice might have been another xeric tree from that area such as little leaf cordia, Cordia parvifolia, which seems to survive to a slightly lower winter temperature. I suggest in the future, permanent trees in your landscape should have a minimum winter temperature of 20F. Suckering from the base is a good indicator it died to the ground, or the trunk was severely damaged. You do not need to replace the tree unless it looks horrible. It is grown on its own roots. Let one or more of the suckers replace what died. Suckers grow very quickly if the roots were not damaged. If a tree does not normally produce suckers at its base, the production of suckers can sometimes indicate the trunk is damaged either from borers or sunburn or both! If you decide you want to keep it, water deeply and infrequently and fertilize it in the spring. Two handfuls of tree and shrub fertilizer about two feet from the tree each year will be enough. Wet the soil, create a slit in the soil with a shovel about 6 to 8 inches deep, drop the fertilizer into the slit, step on it to shut it and water it in. Xeric trees grow rapidly with water applied to them like mesic trees. You will have to search to find this tree at local nurseries.

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Avocados for the Cold Desert?

Q. I have read that Mexicola avocados are ok in as low as 15 degrees once established. Am I wasting my time trying? Or do I need to grow it in a pot until a certain size so I can bring it inside? Love avocados but don’t want to buy something just for it to die. A. Avocados are a real gamble in the Las Vegas area. If you look around town you don’t see too many which is a good indicator they don’t survive here very well. But you are right. If you are going to try one, it would probably be a Mexican race of avocado such as Mexicola, and planted in a protected location. A few of the avocado varieties             The problem is its size. You could keep it pruned below 20 feet which will help keep it from freezing if planted in a warm microclimate and protected from cold winter wind. The other problem is pollination. There is a good chance you will not need a second tree for pollination to produce fruit but you may produce more fruit with a compatible tree for pollination.             Another option is to plant a dwarf avocado such as Little Cado, a hybrid between Mexican and Guatemalan races. This dwarf avocado can handle temperatures down to about 25° F, similar to many citrus growing in Las Vegas planted in warm microclimates. Read more about the 3 races of avocado published by the University of California Riverside http://ucavo.ucr.edu/General/ThreeGroups.html

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