Water, Water, Water: Trees During a Drought

Yes folks, the time has come to look toward spring plantings and watering. Before you flip to the next article, tired and annoyed by this old mantra, please bear with me a few more lines. With very few exceptions, each year in Oklahoma we deal with some type of water deficit from absent spring rains to Augusts when everything not tied down blows away. This year will be no different, but the good news is that we can combat the problems with some useful data, planning, and water, water, water.

The US Department of Agriculture (USDA) and National Oceanic and Atmospheric Administration (NOAA) are reporting that parts of Oklahoma are as much as eight (8) inches below average on rainfall amounts for the twelve (12) month period. Central Oklahoma is holding around three (3) inches below average. This doesn’t mean we should expect another Dust Bowl by spring, as NOAA labels it a moderate drought. However, the USDA and NOAA go on to predict that the drought will persist or intensify (ie worsen) through March.

The bad news is that we’re short on rainfall, soil water resources near the surface are practically exhausted, subsoils are dry, and trees have been struggling for a few months. However, we can combat this problem by watering all evergreens starting now, just a few gallons a week. Once planting begins in late spring, we’ll need to step up watering to approximately ten (10) gallons per week for all established trees and shrubs. Newly planted trees will need extra watering-in when they’re planted to ensure good soil/root connections, and the new trees will need five to ten (5-10) gallons per week after planting. When can we stop watering? The easy answer in Oklahoma is never. The practical answer is that if we have a very wet spring that exceeds normal rainfall totals to make up the amount we’re short, we can slow down watering until July when the next rain deficit is likely to start.

Is there any good news? Yes, there is: the USDA and NOAA are not predicting the drought to worsen past March. The long range predictions can’t tell us for certain if we’ll completely come out of the drought during the spring, but they’re fairly confident it won’t get worse. And when we’re talking water, trees and Oklahoma, that’s pretty good news. Water, water, water!

Replanting After Pine Wilt

After the removals and clean-up from pine wilt’s damage, there are excellent opportunities to continue beautifying your park, school, yard or library: Replant! Below is a list of replacement trees, suitable for Oklahoma, as well as some important characteristics of each.

Pines

  • Shortleaf pine – native to eastern Oklahoma , hardy, moderately dense crown, available in limited supplies from nurseries
  • Loblolly pine – native to eastern Oklahoma, avoid planting in high clay soils, open crown, easily found in nurseries
  • Ponderosa pine – native to western US, it has transplanted well in Oklahoma, moderately dense crown, available in limited supplies from nurseries

Note: The listed pines have a different growth pattern from Austrian and Scots pine. Shortleaf, loblolly and ponderosa pines do not keep their branches to the ground; they have a more “open” appearance than the dense growth of Austrian and Scots pines.

Other evergreens

  • Junipers, improved varieties – native to Oklahoma, aesthetic varieties of eastern red cedar, hardy in almost all soils and locations, drought tolerant, don’t spread indiscriminately, many varieties and cultivars available from nurseries
  • Arborvitae – successful introduction to Oklahoma, prefers soils without high clay content, dense branching and foliage, should not be planted near trees or shrubs with seridium canker, available from most nurseries

Additional information and photos of each tree are available through Oklahoma State University at http://www.okplantid.org.

Oklahoma boulevards are hallmarked by large, old American elm trees. Their stately presence has shaded streets and watched Oklahoma progress from frontier to modern society. As we all know, however, Dutch elm disease has decimated the American elm population throughout Oklahoma, forever changing our landscape.

New American elm cultivars are available that may hold the key to rebuilding our urban forest. Dutch elm disease-resistant American elms recently on the market include ‘New Harmony,’ ‘Valley Forge’, and ‘Princeton.’ With slight variations in form, ‘New Harmony’ and ‘Valley Forge’ being vase-shaped trees while ‘Princeton’ has a more upright form, there is a new cultivar to fit practically any landscaping plan. Two beautiful specimens of the fast growing ‘Princeton’ can be seen at Oklahoma City University’s Native Tree Arboretum, a project gifted to the university by the Tree Bank Foundation. Try one of these American elm cultivars in your next landscaping project, and you’ll see why they are Oklahoma Proven!