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Wednesday - May 18, 2011

From: Kerrville, TX
Region: Southwest
Topic: Diseases and Disorders, Transplants, Trees
Title: Huisache tree is not thriving in Kerr County, TX.
Answered by: Jimmy Mills

QUESTION:

Our landscaper planted a Huisache tree in our back yard (Kerr County). It was planted about 3 years ago. It has grown considerably (about 15 feet tall)but it has never flowered and is always late in leafing out. It is May and the bottom half of the tree is entirely leafed out wth the top half slowly leafing out. There is some dead wood on the tree which I will have to remove but I am unsure when to prune it. I now understand from reading up about these trees that they prefer a warmer climate. Is this a lost cause? Do these trees require any special fertilization to flower?

ANSWER:

Its often hard to determine why a tree won't grow, especially when the tree is several counties away. Mr. Smarty Plants is going to suggest that you contact the folks at the Kerr County Office of Texas AgriLife Extension for some help closer to home.

Next, lets learn a little more about the tree. Huisache is a native shrub or tree that is well suited to the Hill Country as is confirmed by this article from the Native Plant Society of Texas. It is hardy in Zone 8, and is close to the northern end of its range in Kerr County. This past winter probably didn’t do your tree much good. Looking at its Native Plant Database page will let us see what the plant needs to grow.

Growing Conditions
Water Use: Low
Light Requirement: Sun
Soil Moisture: Dry
CaCO3 Tolerance: High
Drought Tolerance: High
Heat Tolerant: yes
Soil Description: Sandy, Sandy Loam, Medium Loam, Clay Loam, Clay, Caliche type
Conditions Comments: Acacia farnesiana can form dense thickets from suckers. It has small, fragrant, orange-yellow flowers cluster in globose heads. But blooms so early that buds are often ruined by frost in the northern parts of its range. Acacia beetles can girdle limbs up to 3 in. across. Alkaline tolerant. This beautiful tree casts a soft filtered light but be careful when planting it, because it has sharp thorns on the trunk and branches.

Now we need to ask a few question; Is it getting full sun? What about water; too much or too little? Many people tend to overwater new trees. What kind of soil is it growing in? What does your landscaper say about the tree?

Since the tree was planted only three years ago, in could be experiencing transplant shock. These two links from Purdue University and the University of Kentucky can help you deal with this possibility. As for pruning removing dead wood can be done at any time.

Huisache has been flowering for centuries without being fertilized by humans. One should never fertilize a plant in stress. Too high a ratio of nitrogen to phosphorous (ie more nitrogen in the soil than phosphorous) inhibits flowering in some plants. This could happen in your case if the tree was getting too much lawn fertilizer which usually has high nitrogen levels.

Acacia farnesiana