Helping Mature trees in drought

[midwestcoast]

I've got nearly a dozen full-sized trees on my small lot & some are really showing signs of drought-stress. So far the mulberry, elm and one locust seem okay, but all 5 Silver Maple are dropping leaves enough that I'm concerned for their health. All are likely around 60 years old as that's the age of the house & neighborhood. The soil here is pure sand below about 18" of topsoil.
Besides the gardens I have been watering a few young trees & shrubs about every 10 days to keep them going. The lawn has been "dormant" (the polite term) since mid-May.
I definitely do not want to lose any of the Silver Maples, so how do I help them?
I have a 10' soaker hose that I put on one of them for about 3 hours last night, moved it once. I kept it near the drip line. I have no idea how much water to give each tree and don't want to use more than needed. Any rules-of-thumb?

 

[dave11]

I recall reading in an arborist sort of book that a large maple tree can use 100 gallons of water each day in the summer. That's what it takes to be healthy. When you think of the necessary transpiration and the large leaf surface area, that doesn't sound like quite so much. Nonetheless, I'm not sure what the minimum is to keep such a tree alive. Surely it depends on lots of other factors.

We haven't had any significant rain here in nearly 50 days, despite the heat. The leaves are drooping on the big trees, though only the smaller trees and the shrubs show any branches dying.

You could go broke trying to water your large trees enough to make a difference, but you might pick one tree per day and water just that one. A deep soaking of one tree would do more good than surface watering of several. Check how many gallons per minute your hose can deliver, and aim to give each tree 50 gallons, spread under its canopy. I'd just use the hose, and not use a sprinkler or the soaker hose.

 

[begreen]

We often have Mediterranean summers here with little or no rain. (So far only about 1/4" in July at our house.) Depending on the soil and its dryness, surface watering can take a long time to percolate down to the roots. I use a water injector when the trees get weepy, but they are smaller than your mature trees. It injects water 1-2' down into the soil instead of at the surface. I use a Ross root feeder, without adding feed, but you can make one.Water around the dripline divided into 8ths. For a big tree I would let it run about 5 minutes per injection or about 40 minutes per tree. Check for injector hole plugging once in a while and clear our if necessary.

There are several products on the market like the tree I.V. or the Ross feeder that will do the job. The principal is simple and you can probably make one yourself if you're handy by using a 3 ft length of 3/8" pipe, with a point welded to one end and holes drilled near the tip. Top it with a tee and 2, 6" nipples to make the handles. Cap one nipple and adapt the end of the other up to hose thread. If you want to get fancy you could put a ball valve on it.

Here is a commercial model:
http://www.nu-arbor.com/files/spwgPCp67usxt0Mi/dQVLh4RyibVtKnb1/ManualPartsDiagram3.pdf

Here is the Ross unit that I picked up on sale:
http://www.amazon.com/Ross-1200C-Heavy-Feeder-12044/dp/B00002NC84/ref=sr_1_2?ie=UTF8&qid=1342371388&sr=8-2&keywords=ross root feeder

Looks like there is an older model on sale at ebay (used) http://www.ebay.com/itm/Used-Ross-1...ertilizer_Soil_Amendments&hash=item2a1fffc1f9

tree i.v.

 

[begreen]

And don't dismay if the maples lose their leaves early. It's a survival tactic to conserve moisture in the body of the tree. They can often survive a single season drought.

 

[Defiant]

You could go broke trying to water your large trees enough to make a difference, but you might pick one tree per day and water just that one. A deep soaking of one tree would do more good than surface watering of several. Check how many gallons per minute your hose can deliver, and aim to give each tree 50 gallons, spread under its canopy. I'd just use the hose, and not use a sprinkler.

I agree with you Dave, try to soak one or two trees a day, early AM I feel is the best time. Just read your post BG some great advice also.

 

[midwestcoast]

Thanks for the responses. Most everything I'm finding with Google is about the drought last year in Texas. It's saying to water 'till it penetrates to about 6-8" depth and around the drip-line because that's where the most feeder roots are.
50 gals x 1 tree per night sounds like a plan.
Injecting underground seems like a very good idea. I don't need to be putting water down just to have it evaporate.

I first thought it would be too much water to help these trees, but then I got thinking about how much they are worth to me in shade for the house & yard, aesthetics, squirrel watching... 50 gals a day is a lot, but hopefully we get some rain soon!

 

[fossil]

http://www.google.com/#hl=en&gs_nf=....,cf.osb&fp=b61e6e24eede373b&biw=1447&bih=685

 

[Backwoods Savage]

Trees dropping leaves are like lawns turning brown and dormant. It is just one way to combat the drought. Most trees will survive this but the young trees might suffer. I have not watered anything yet but will water the fruit trees if they get too bad. I am amazed at how many raspberries we are getting even with very little rain. No apples or peaches this year though.

 

[begreen]

With our fruit trees, you can see them responding to root injection watering within a few hours. I water them in the evening and by the next morning the wilting leaves are open and full. For the past few years I've also been nurturing a young red maple via this method. It's now about 15 ft tall and looking good.

 

[save$]

Put a big plastic trash can or two under the tree. Drill a few small holes in the bottom of the tash cans. Then fill the cans from your garden hose. The water will leak out and slowly be absorbed and not run off, or evaporator from the surface. Alway a good way to get water where you want it.

 

[Defiant]

We were very fortunate last night to get a nice mellow 1&1/2"s of rain. Vegetation, bugs and birds very happy.

 

[maple1]

I'm not sure I've ever heard of a mature tree dying from dry conditions?

 

[midwestcoast]

I'm not sure I've ever heard of a mature tree dying from dry conditions?

The Texas drought last year killed a lot.
I know they are not about to just die-off, but there's a good 2 months of hot weather this year & I'd like to keep the shade if I can. It was 102 here yesterday. That's 39 Celsius!
Also don't want them weak & susceptible to disease... in coming years.