by Tom Spencer / Soul of the Garden
There is an old proverb that says, “If you wish to be happy for a year, plant a garden. If you wish to be happy for a lifetime, plant a tree.” Unfortunately, most tree buyers are looking for a quick fix; they want something that will take significantly less than a lifetime to grow. Our fixation on quick-growing species has resulted in entire neighborhoods being riddled with disease-prone, insect-infested trees. Often, these plants die just as quickly as they have grown, endangering our homes and providing full-employment for the arborists who clean up the mess.
While I understand the urgency of shade in Central Texas, I am an advocate of the slow-growth, long-lasting urban forest. Trees are our most enduring legacy as homeowners and gardeners, and if we choose wisely, the trees we plant will have the potential to make our grandkids happy too.
Fall is the best time to plant trees in Central Texas; the coming weeks will bring cooler temperatures and can usually be counted on for at least occasional rain. Soil temperatures at this time of year remain warm enough for the newly planted trees to send out exploratory roots, giving them a head start on next year’s growing season and helping them clear the biggest hurdle of their leafy lives: their first Austin summer.
Before I dive in and start telling you which trees you should plant, I urge you to really think strategically about where you plant them. Trees are, due to their size, the centerpieces of our landscapes. They should be the starting point for any well-conceived landscape plan. Planting trees in a given location may frame or block a view, shelter a patio or roof, provide a focal point, or create an island of shade for a hidden retreat. The most basic consideration is the scale of the tree as it will be, not as it is when you have brought it home in a five-gallon container. Do not plant a Bur Oak, which will grow to towering heights, underneath a power line or under the eaves of your home!
The Oaks represent the alpha and omega of desirable shade trees for Central Texas. The classic Austin tree, the Live Oak remains, for many, the “gold standard” of native trees. There are actually several different forms of Live Oak that call Austin home: the Coastal Live Oak (Quercus virginiana), the Escarpment Live Oak (Quercus fusiformis) and hybrids with genes somewhere between these two. (Oaks are notorious for messing around in their own gene pool.) The Coastal Live Oak is the majestic tree that we associate with the Old South with its low-spreading dome shape and massive limbs. It is one of the most heavily planted trees in the city and is widely recognized a “the” tree of the University of Texas campus.
The Escarpment Live Oak is the oak of the Hill Country and is well adapted to the thin caliche soils and less generous rainfalls of that region. Typically, this tree will remain somewhat smaller in stature than its coastal cousin and often develops a cluster or “motte” of trunks.
While both these species of Live Oak are susceptible to the notorious oak wilt fungus, if they are planted in an area that is free of the disease and are well maintained, there is no reason not to invest in one of these beautiful long-lived trees.
There are two oak wilt-resistant varieties of Oak that are proven “legacy” trees for Austin. These are the Chinkapin Oak (Quercus muhlenbergii) and the Bur Oak (Quercus macrocarpa). Both of these are large deciduous trees with a moderate rate of growth. While these trees are not as common as the Live Oaks, there are quite a few stately specimens scattered around Austin.
The Chinkapin Oak is well adapted throughout our region and can grow in either the clay soils common east of the hills, or in the caliche soils of the Hill Country (where it grows naturally in sheltered canyons). When it is young, the Chinkapin tends to have a symmetrical upright form. When it matures, it gets middle-aged spread, shading a wide area with its large handsome leaves. I tend to use a lot of superlatives when I talk about Chinkapins. One of the reasons I am drawn to this tree is that it reminds me of the great woodland residents of the East, where I grew up.
The Bur Oak is the classic Oak of the prairies. In Central Texas it is best adapted to the deeper clay soils east of the Balcones Escarpment. My neighborhood (adjacent to Shoal Creek) has several magnificent specimens of this tree. The leaves of the Bur Oak are often called “fiddle” shaped because of their deep rounded indentations, the name “Bur” refers to their fringed acorns, which can be as large as a golf ball. If you have the room, and want a healthy, stout, giant of a tree, then plant a Bur Oak.
Two other species of Oak that are relatively new to the marketplace show great promise. They haven’t been around long enough for us to consider them “legacy” trees just yet, but all signs point in that direction. Both are oak wilt-resistant.
The first of these newcomers is my all time favorite native tree, the Lacey Oak (Quercus glaucoides). Also called Texas Blue Oak because of the blue-green cast to its leaves, the Lacey Oak is extremely drought tolerant Hill Country native and is perfectly suited to smaller yards that might be overwhelmed by a Chinkapin or Bur Oak. A real bonus with the Lacey Oak is the promise of fall color; some years are better than others, but when the weather turns out just right, Lacey Oaks turn a beautiful shade of orange-red just after Thanksgiving.
The other new kid on the block is the Monterrey Oak (Quercus polymorpha). This is the Oak for those with a hankering for speed. Some of these trees have been known to rocket when they are young, growing quickly in a narrow pyramidal form before developing a spread as they mature. Native to the Western reaches of the Hill Country and Northern Mexico, this drought tolerant plant is usually evergreen in most Austin winters and is well adapted throughout our region.
This autumn set down roots that will last for generations: plant an Oak and make it your legacy to Austin.
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