As I talked about in my last post, patience is the watchword for freeze-damaged plants this spring. This past winter has been harder than we have seen in at least five years. When weather patterns persist for several seasons it can be tempting to install plants more suited to the perceived “new normal.”
In response to the drought, many have gone completely to xeriscaping. In other times plants have been selected for high water needs due to a couple of years of above average rainfall. Landscapes have been done over in tropical plants because it seemed that high heat and humidity were here to stay. In all cases this work is undone by a single season of aberrant weather.
As an example, agave (Agavaceae) has gained favor because of its heat tolerance. Unfortunately, many of the extensive plantings won’t survive a harsh winter with several days of freezing temperatures. It literally melts in freezing temperatures. Agave is also sensitive to overwatering so the summer of 2007 when it rained nearly every day from May through July would have been disastrous for this plant.
Another example of a plant frequently installed in the Dallas-Fort Worth area is Mountain Laurel (Sophora secundiflora) which is more suited to Central and Southwest Texas. Freezing temperatures can easily kill this shrub.
The Wisdom of Neil Sperry
Several years ago I heard something from Neil Sperry that has stuck with me over the years. He said to remain loyal to plants within the region’s temperate zone. In other words, it is best to design the majority of your landscape with plants, trees, and shrubs best suited to the average environment. Here in Dallas-Fort Worth that is Zone 8a where the minimum temperatures for plant hardiness are around 10-15 degrees.
For the past several seasons plantings have skewed toward more tropical zones. With such extended heat and drought it’s easy to think it will continue to be this way. But this winter proved differently. Plants that are more suited to Houston, Austin, and the Gulf Coast have been planted in abundance and now there are large tracts that will require expensive replacement.
Hew to the Middle
There is nothing wrong with setting aside a small portion of your landscape or garden for plants from zones outside ours. But to devote your entire design to specimens that are tolerant of more cold, heat, water, or drought than is typical for this area will wind up hurting your bank account as well as your landscape.
Plant Nellie R. Stevens holly instead of Japanese Ligestrum. Think of golden lantana as an annual, not the perennial it is in Houston. Plants from the middle of your temperate zone may struggle in years of extremes but are much more likely to survive to bloom another spring than those from warmer or colder zones.