Publications (Paul's Blog)

September 13, 2011

Filed under: Uncategorized — Paul Dowlearn @ 3:46 pm

How long does it take a tree or shrub to become established? That’s a fair question that we get asked very often. What people want from a professional is a definitive answer. The stock answer I learned from professionals who mentored me is three to five years. That gives some leeway and a difference of 66% longer in the case of five years. Not exactly what people want to hear.
A more honest answer would be to say when that we observe vigorous top growth is a good sign the tree is becoming established. Once the tree is established we can expect the tree or shrub to survive on rainfall without the constant need of supplemental irrigation. Provided, of course, you have planted a tree that is native to your region or at least one that is well enough adapted to give you that expectation.
Choosing plants that will survive your particular climate is absolutely critical. Trees and shrubs have a very long life span. Any native or well adapted tree or shrub should potentially last a lifetime. Choose wisely or be prepared to be disappointed. I am a collector and enjoy experimenting but I have learned most experiments fail. If for instance you would like to grow a banana tree my advice would be not to invest heavily unless you live in the tropics or own a very tall greenhouse.
Native trees and shrubs are as close to perfectly adapted as it gets. Therefore, they will establish quicker and get back to normal growth sooner. Well adapted exotics may take longer whereas poorly suited trees and shrubs may not ever be able to grow without extra irrigation and other special conditions provided by the owner.
For instance, most people assume that a fast growing tree would establish faster. That would be true in the case of native trees that grow fast. However, I have seen many examples of trees that are touted to grow astonishingly fast that never make it to maturity here in the Rolling Plains. These trees are most often found in the mail order industry and claim growth rates of eight feet per year or more. No doubt that is true under ideal conditions and in the native habitat of that particular tree. Your best bet is to shop with a locally owned nursery. They have a reputation to uphold and know what will work (or not) in your area.
On the subject of growth rates, that is another area in which there are so many variables that we cannot give definite answers. In truth, there is no such thing as a growth rate. This year of drought has brought this home to many observant people. In 2011 it has been about survival. Many newly planted trees and shrubs are struggling with the dry atmosphere on top of the stress of transplant shock. We are actually seeing negative growth rates this year. If you read or hear about growth rate for a particular plant, bear in mind that these rates are quoted as an average. Just like our weather averages that so far have been anything but average this year.
We often get calls from people who say their new plants look alright but just aren’t growing. They are growing roots. The roots always come first as can be observed on any seed as it germinates. The root always appears before the seed will initiate top growth. As soon as the roots of your new tree or shrub are no longer restricted by the plastic container that once held them, they begin to grow outward into the soil. The entire plant is fed from chlorophyll manufactured by the leaves so immediately after planting most of the energy goes to the roots. Regardless, the part of the plant that is visible to us is the top and we tend to make assumptions based on that or some growth rate that is merely an average.
In spite of these facts that prove there are no easy answers to the time it really takes for establishment, there are some things we can do to shorten that time between initial planting and when we can wean trees and shrubs off the water hose.
1. Go Native: I can’t stress this enough. Your local natives have evolved with your climate, soils, and other conditions that may exist. All other plants, no matter how well adapted or reliable have not had this advantage.
2. Use beneficial microbes: This is the cutting edge of the industry today. Mycorrhizal fungi and rhizobacteria form lasting relationships by colonizing roots. This gives a much greater benefit than fertilizers or root stimulators.
3. Compost: This is the fertilizer of choice. Compost supplies all necessary nutrients plus provides the correct habitat for beneficial soil microbes. Mix compost in the upper 3 to 4 inches of your native soil then supply an additional inch as much.
4. Mulch, mulch, mulch: Add additional layers of organic mulch on top of your composted soil. This is very beneficial in creating the type of soil profile found in natural woodlands. Widen the circle of mulch as your plants grow.
5. Irrigate deeply: Trees and shrubs benefit from deep moisture as opposed to constant shallow applications. Drip or slow irrigation accomplishes this goal best. Irrigate frequently at first then gradually less as plants become established. Eventually you should stop supplemental irrigation altogether with the exception of extreme drought years.
The establishment period is extremely important because transplants experience different levels of stress until they have had time to get roots established in your native soil. This means true cold hardiness, drought tolerance, and/or disease and insect resistance don’t kick in until the plant is firmly established. In fact, the plant is quite a bit less tolerant of any additional stress factors like these when it is first planted.
Trees and shrubs planted in deep fertile soils will naturally grow faster than the same variety planted in tightly compacted or thin soils over clay subsoil. This holds true even if you plant fast growing varieties. If you live in an area that has tight soils, all the more reason to look at your local natives for plants that do well in that type of soil. Yes, believe it or not, there are places where trees like mesquite become very valuable. I happen to live in one of those places.
Some of the new trees I planted earlier this year may not make it through this terrible drought but I am confident the mesquites will. Trees and shrubs are the backbone of our landscape. Proper culture and maintenance will result in a lifetime of reward. Unfortunately this does take time and truthfully there is no way to predict exactly how much time it will take especially when we have weather like we have experienced this year.
Trees should be the very first item on your landscaping list. If you have need of shade or screening you should plant as soon as you can even if you can’t afford to do much else. Early fall through late winter is the ideal season to plant.

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