When should I plant 15 gallon Ash trees?

Question

I live west of Phoenix, AZ. I am planning to plant four 15 gallon Shamel Ash trees in my backyard. I do not want them to die from the heat... but I want them to have a chance to get roots before the winter freeze. The average temperature right now anywhere from 100-110 degrees with random humidity. We are having a somewhat rainy season, so the temp and humidity vary by day. It can get as hot as 120 degrees in August. Is there a certain temperature range I should look for before planting my trees to prevent them dying from sunburn or heat???

I do not have the trees yet, I am planning to purchase them... so they are still living happily at the nursery, not in pots in the yard... LOL. I am wondering the best time to buy them... the nursery will plant them professionally for free.

Answer 1

Having them in the ground would keep the roots cooler than in a pot.

It is probably best to go ahead and plant them. Just be sure to keep the roots cool and moist. I'm having to water a couple or 3 times a week here in SoCal. You're getting more monsoon rain that I am here.

Be sure to put a good layer of mulch over the root zone. A couple of inches of bark or compost.
Water deeply. If your soil is clayey you will have to put down lots to get the soil moisture deep enough. I put down an inch or two at a time, in a basin out to the dripline. Use some of the soil from planting (you will ammend the soil I hope) and make a little damn3 or 4 inches tall. Just fill that twice and the trees should get enough.

You could also get some floating row cover to wrap the top with. It can hold in humidity and will keep the sun from scorching the leaves. It looks odd, but works. I've done it with a few trees (5 gal size) and had better survival.