Plant Diseases/olive trees are dying!
Three weeks ago we purchased 3 arbequina olive trees about 2 years old. They were in 5 gallon vases and now are in soil. We live in Arizona. Gardener who planted them told us to water them once a week with a bucket of water each. When we got the trees they had a couple of brown leaves he said was due to frost, nothing major though. Now all trees have more brown leaves, but I am concerned more about one that has more brown leaves than green now! We did have about a week ago 3 days with frost temperatures in the night around 20 degrees. I asked others and they told me it's unlikely the frost is killing them but lack of water! I was told when they are transferred to soil they need more watering than a bucket a week to establish. The soil was very, very dry so we watered them last night instead of waiting another 4 days. We are expecting another 3 days when the night is expected to go down in the 20 range again. How can I protect them? I touched the brown leaves on 2 trees and they were very crisp and fell off right away. I removed all of these dry dying leaves. The tree in the picture concerns me the most, it's all brown almost, but when I touch the leaves they do not fall off as the other trees. Advice highly appreciated, what can I do? we spent over 200 dollars for these trees!
Water is crucial at planting time and during establishment. They need to have a good consistent supply during that time. The soil also needs to drain easily. Too much clay in the soil can create a water logged situation that leads to root rot and tree death. The transplant period is stressful- that is the period of time that the newly planted tree is getting established to its new surroundings. There is often some leaf browning during this establishment period. A better way to check the life/death status is using your fingernail, scratch a small area of bark off on a few of the smaller twigs (small scratch- 1/4 long) at various locations on a tree. Look for green beneath. This is a good sign. Brown below isn't. The twigs should also flex w/o snapping. If they snap off, this is usually a sign that the twig is dead and brittle. You can also check the soil to see how moist it is by digging a bit in the immediate area. It should not be soggy, but moist.
When freezing temperatures are expected, you may wish to drape an old sheet or cloth over the tree and the wire cage for the night and until the sun comes out the next day. Do not use plastic that could come in direct contact with the leaves. Plastic can burn the leaves when the sun is shinning.
Don't give up yet. Trees have a way of surviving some real hard times.