Raywood Ash Problem - Knowledgebase Question

Surprise, Ar
Question by shamill2
June 30, 2010
I purchased a 36 inch boxed Raywood Ash in April of this year. It was thriving until about 3 weeks ago. It is dropping all of it's leaves, and they are getting very dry. I live in Surprise AZ, and it is getting very hot. The tree is getting deep soaked twice a week for about 3 hrs, and is on a drip system four times a week. The branches are getting brittle, and the leaves are crunchy. HELP

Answer from NGA
June 30, 2010


Effective watering is the most crucial thing for new transplants. Running drip four times per week is not effective for deep watering a tree because the root ball doesn?t get moistened unless you run the drip for a long time and/or have lots of emitters with a high gallon per hour output. For example, an emitter that puts out one gallon per hour would only put a quart of water on the ground in 15 minutes. Desert soil and water both contain salts, which can accumulate in the root zone over time. This salt buildup forms where the water stops penetrating. If you ?sprinkle? plants lightly and frequently or run drip irrigation for short periods, the root ball doesn?t get moistened. Salts will build up in the top layers of soil and damage or kill your plant. Deep watering?or leaching?prevents this by flushing the salts past the root zone. Always water slowly, deeply and as infrequently as possible.

Your deep soaking is the best practice, assuming water is soaking through the root zone. For trees, water should soak 3 feet deep. Use a soil probe (any long, pointed piece of metal or wood to poke into the soil) to check how far water has penetrated. The probe moves easily through moist soil, but stops when it hits hard dry soil. There are numerous variables involved for watering schedules, such as type of soil, how fast or slow it drains, sun and wind exposure at your site, temperature, age and condition of the plants and much more. Before automatically applying more water, stick your finger into the soil. Apply water when it is dry down to about 3 inches. Gradually reduce the frequency of your deep watering as the roots establish to once every 7 to 10 days in summer.

I'd suggest continue deep watering, but eliminate the drip. If you want to keep it on a drip system ensure that sufficient water is applied to soak the roots as described above. Depending on the size emitters, soil type, etc. this might take several or many hours. As a tree grows, its new roots tips, where nutrients are being absorbed, spread out laterally. Expand your watering zone out PAST the tree's canopy as it grows. If you use an irrigation system, you need to move the emitters out. If you use a hose, just drag it out further. Apply several inches of organic mulch over the entire root zone to help maintain soil moisture and reduce soil temperatures. I hope this info helps.

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