Deep Root Fertilization of Trees (Austin, Live Oak: house, neighborhood, construction)

[G Grasshopper]

We moved into our house in SW Austin in April. I just had an estimate on taking down a large branch of our live oak that is imperiling our roof, and also taking dead branches off the burr oak in the back. But the guy (from Davey tree service) also gave me an estimate of $165 to deep root fertilize all the oaks (we have 3 in the front and 1 in the back.) So is this a good thing to do? He said that it is timed release, and feeds them for a year. The trees seem generally to be in good shape, and are not showing signs of stress from the drought. I do deep water them some. So should I have this guy do the fertilization when they come to do the pruning? What has been people's experience?

[10scoachrick]

Nearly everything I've read tells us NOT to fertilize during a drought AND not to prune significantly during a drought. HOWEVER, you mention your deep watering, so perhaps your trees aren't 'suffering' from the drought conditions. ALSO, a slow release fertilizer MAY be OK, even though we have the dry conditions. I last used a all-natural spray-on fertilizer back in the spring...nothing but water since then and I'm waiting to de-sucker our Live Oaks because of the drought conditions.

The pros should know their stuff....BUT, they are there to sell you something after all.

Good luck!

[motherofthree]

Don't do it. It's not needed. I don't know how large your trees are but once they are well established fertilizer is not needed. Best thing to do it to spread compost under the canopy of the tree twice a year and water when in drought.

[CptnRn]

Originally Posted by 10scoachrick

Nearly everything I've read tells us NOT to fertilize during a drought AND not to prune significantly during a drought. HOWEVER, you mention your deep watering, so perhaps your trees aren't 'suffering' from the drought conditions. ALSO, a slow release fertilizer MAY be OK, even though we have the dry conditions. I last used a all-natural spray-on fertilizer back in the spring...nothing but water since then and I'm waiting to de-sucker our Live Oaks because of the drought conditions.

The pros should know their stuff....BUT, they are there to sell you something after all.

Good luck!

Agreed, the City of Austin Arborist was quoted in a recent newspaper article advising against fertilizing trees during a drought.

This advise is repeated here on the City Arborist website: http://www.ci.austin.tx.us/trees/en_maint.htm (broken link)

Watering

If we experience significantly dry conditions citizens of Austin and surrounding areas are advised to water desirable young trees and valuable landscape plants. Problems occur when plants are subject to extended periods of low soil moisture. Trees that are young, those on shallow soils, and plants under construction stress will be at potential risk of damage unless supplemental watering is accomplished. An intense downpour quickly runs off and small volume rain events will not necessarily end the need to water.

The practical approach for watering trees is to locate an unrestricted hose end six feet from the base of a medium sized tree. Trickle water at the rate of one gallon per minute. Water small plants for 1-2 hours, graduating to a duration of 12 hours for large trees, which should be watered out to the dripline area. Move the hose to different sides of the plant every few hours. Additional measures that are beneficial to drought stressed plants include:

Apply compost into or over the plants' root zone;
Avoid the use of fertilizers during hot and dry conditions;
Spread one to two inches of mulch material within the root zone; and,
Consider replacing poor performing plants with native trees and shrubs.

Here the Texas Forest Service recommends:

http://lufkindailynews.com/life/comm...cc4c002e0.html

■ Don’t fertilize trees during a drought because fertilizer can cause root damage if there is not enough water. The tree also needs to slow down its growth in dry conditions.

[G Grasshopper]

Thanks, everyone. I am going to have the guy take off the dangerous branch (making sure they seal the cuts) and the dead ones, but I will forgo the deep fertilization. I would rather go with the more natural, compost method anyway. The bur oak in the back was stunted on one side by an overgrown, poorly placed crepe myrtle. I have taken that down (my son and I removed it), and am just wanting to encourage the tree to grow out on that side. That is why I thought we should remove the dead branches on the stunted side. All these oaks, by the way, are adults, not new trees.

[love roses]

Yeah, I wouldn't deep fertilize a mature tree either. My husband bought some time release tree spikes for our oaks when we first got our house. They ended up growing pretty well and we don't fertilize them anymore. They shade the whole front yard and people say they're the biggest in the neighborhood now. I'm not too proud of them am I?

[10scoachrick]

Originally Posted by 10scoachrick

Nearly everything I've read tells us NOT to fertilize during a drought AND not to prune significantly during a drought. HOWEVER, you mention your deep watering, so perhaps your trees aren't 'suffering' from the drought conditions. ALSO, a slow release fertilizer MAY be OK, even though we have the dry conditions. I last used a all-natural spray-on fertilizer back in the spring...nothing but water since then and I'm waiting to de-sucker our Live Oaks because of the drought conditions.

The pros should know their stuff....BUT, they are there to sell you something after all.

Good luck!

Not that it means a hill of beans...as I re-read the above phrase, it looks like I made the old your/you're swap. However, I was referencing the 'deep watering' as his/hers/theirs, not saying 'you are deep watering'. I make plenty of mistakes(especially since I'm on the computer at really stupid hours of the wee morning); BUT, I REALLY try not to fall into the your/you're, sale/sell, then/than, they're/there/their morass that seems to afflict WAY too many message board enthusiasts. Thank you for your time. Now, back to our regular programming...