The Struggle to Grow Native Trees in Southern Texas
Trying to grow native trees in my yard in southern Texas, just south of Houston, is a constant battle. It seems to be one of the most inhospitable regions for growing native trees, apart from the handful of species that grow naturally in this exact region - these species are the ubiquitous Live Oak, Pecan and Sugarberry, and scattered Green Ash, Water Oak, Cedar Elm, American Elm, and Black Willow. In nearby Brazos Bend State Park I have also seen Burr Oak, Swamp Chestnut Oak, Shumard Oak, American Sycamore, Eastern Cottonwood, Western Soapberry, Water Locust, Water Hickory, Ashleaf Maple, American Hornbeam, Overcup Oak (2 specimens), and Bald Cypress. Most of the native trees I am collecting grow naturally about 100 miles northeast of where I live and beyond, where there is a tremendous variety of trees (for example the Big Thicket region). For some reason, my exact area is just not very tree friendly. It could perhaps be the soil. My soil is orangey-brown clay with a pH of 7.0 - many of my trees are supposed to feel more at home in a slightly more acidic soil. However, I've been told by tree planters that I have "good dirt" - it does drain pretty well after heavy rain (apart from the southeast corner which can stay waterlogged for several days after a few inches of rainfall). The clay soil becomes horribly sticky and squelchy after a lot of rain, and in the baking summer when it almost never rains, it becomes as hard as concrete. My constant battle to keep the trees alive and healthy is waged against the following main foes: heat, insects, diseases, wind, waterlogging, and mysteries.
(1) INTENSE BRUTAL HEAT AND SUN I have lived in Texas now since the summer of 2011, and although the weather can be very variable in winter and spring, the summers (mid May to mid October) are ALWAYS brutally hot with almost no rain. The daytime temperatures are almost always above 95 degrees Farenheit and the humidity is usually high. This means that it is a constant struggle to keep the trees hydrated during the summer. For some tree species, even 3 or 4 days without watering can lead to massive leaf browning and loss. As I possess more than 60 trees, this means lots of evenings and mornings in the yard watering the trees. I used to use a drip-irrigation system which comprised 815 feet of tubing which I layed down around the yard from tree to tree, with side-branches to provide water to each tree. This was connected to a timer and worked really well. The only problem was that every time the yard needed to be mowed, I had to take up the whole irrigation system. Putting it down and taking it up took ages and was a very unpleasant task in the sweltering heat so I no longer bother with it, which means I have to manually water instead. In 2018 and 2019 I manually watered only at the weekends which did not seem to be enough in the most intensely baking weeks. For 2020 I have bought a couple of sprinklers which I hope will help.
(2) INSECTS Every year I discover new types of insects intent on consuming the trees. Although I treat most of my trees with systemic insecticide (imidacloprid), it does not seem to work very well on a lot of insects. The worst insect by far, infesting my yard every spring in a rampant ravenous plague and capable of completely defoliating a tree's new growth in a couple of nights is the JUNE-BUG. Most people I know don't even know that june-bugs eat leaves at all, and I have asked folks in local tree nurseries whether june-bugs are an issue for them - they say no. Well, for me they are an absolute nightmare - they appear in late February or early March (not June despite their name) at night time and descend on every deciduous tree that has leafed out, in their thousands. At first, it's only the Water Oak and Sassafras which are my first trees to leaf out (February 26th in 2016), but as each new tree leafs out, it falls victim. The june-bugs especially like the deciduous oak trees, with the Shumard Oak, and Overcup Oak having been particularly devastated in the past. I have seen several types of caterpillars eating leaves, including "fall web-worm" which has infested the Bald Cypress and Sweetgum trees; the "imperial moth caterpillar" which has become gigantic at the expense of my Burr Oak and Overcup Oak's leaves; "juvenals duskywing" caterpillar which consumes the newest growing leaves at the branch tips of of my Cherrybark Oak; something similar to a "twin-spotted sphinx" caterpillar which was eating leaves on my Pecan tree; "forest tent caterpillar" which erupt in massive swarms and quickly defoliate soft leaved trees; "bag-worms" which infested my bald-cypress in 2016 and Eastern Red Cedar in 2018, causing significant defoliation, and other unidentified caterpillar species, one of which demolishes leaves on my Cottonwoods. Beetles are also an issue. Some kind of flathead borer beetle was responsible for girdling my second sweetgum tree 5/6ths of the way around the trunk, leading to loss of the top 4/5ths of the tree. The "cottonwood leaf beetle" skeletonized multiple leaves on my two cottonwood trees. Actually even bees do damage to growing buds on my Cottonwoods as they collect propolis for use as glue in their hives. Spider mites seem to be a severe issue for my Bald Cypress tree which rapidly turns rusty yellow in early summer, and for my Willow Oak which gets so rusty it loses most of its leaves by the end of summer. Fire-ants are a continuous presence in my yard despite frequently treating the nests with different poisons. I don't think they really harm the trees, but they certainly harm me when I'm trying to water them. I would say I get an average of 3 bites every weekend - for example on July 24th 2016, I got about 25 bites on my right foot from an invisible nest next to the Chinkapin Oak. In one heavily treated patch of my yard, the fire-ants became totally immune to Over 'n Out and Amdro.
(3) DISEASES My yard is absolutely rampant with diseases. I don't understand why so many of the perfect-looking healthy specimens I have bought from local tree nurseries have leafed out the following spring riddled with various disfiguring diseases. (a) "Anthracnose" fungus is a common one. My White Oak used to get this very badly during its first couple of springs. Other trees also seem to have this fungus to various degrees. (b) "Oak-leaf-blister" fungus ravaged my Water Oak in the spring of 2015 and my Willow Oak in the spring of 2016. (c) My October Glory Red Maple looked like it was suffering from "bacterial leaf scorch" before it died. (d) The smaller of my Cottonwoods suffered severely from some kind of fungus in 2018 and 2019, resulting in total leaf loss. Interestingly, the larger Cottonwood which is right beside it, seems relatively immune.
(4) WIND Every spring, just after the fragile new leaves have emerged, it gets really windy. This wind absolutely shreds the leaves of my Swamp Chestnut Oak, Carolina Basswood, and Water Tupelo, and to a lesser extent my Overcup Oak, so these trees look ugly and ragged by the time they transition into the brutal summer. It also used to blow most of the new leaves off the American Beech, and they would never grow back. The wind broke off three major branches from my newly planted nut-laden Pecan tree. Our first hurricane was Hurricane Harvey in late August 2017. The winds were strong but the only tree that suffered was my top-heavy Longleaf Pine which was blown to a 30 degree angle - I staked it upright and it seems OK.
(5) WATERLOGGING In spring of 2015 it rained a lot. The southeast corner of my yard got waterlogged for at least a month and all the non flood-tolerant trees there died. This included my 30 gallon Tulip Tree (which was already struggling due to being incapable of rooting outside its planting hole), my Eastern Redbud which within a week went from vibrant green to deathly brown, and a peach tree which was there when we moved in ( I wasn't too upset about that one as the peaches were tasteless and it's not a native tree anyway). My Carolina Basswood and Black Walnut lost all their leaves during the waterlogging, but managed to come back to life in the spring of 2016. My Sassafras drowned in the autumn of 2018 when the yard was sodden for a couple of months.
(6) MYSTERIES - Why does my Honeylocust sometimes drop almost all its leaflets in spring while still green? - What stripped off several large patches of bark from my Live Oak and my Pond Cypress? - Why is my Bald Cypress getting steadily yellower since 2015, after being vibrantly green in 2014? ----- answer: Bald Cypress rust mites - Why is my Sycamore since 2015 now in the habit of developing yellow / brown leaves in early summer? - Why do my Magnolias struggle so much in my yard, but seem to do so well in other local yards where I've seen them thriving? - Why does my American Elm lose all its upper leaves by mid summer every year since 2017?