Q: I had an Arizona ash tree planted in my front yard last month. It is approximately 10 feet tall and the trunk is 2.5 inches in diameter at the base. The lower branches are 3 to 4 feet in length and spindly. As such, they droop like a weeping willow. Is this typical for an Arizona ash that was in a 24-inch wood box, or should the lower branches be pruned?
A: The small branches of Arizona ash do droop down even though the overall effect of a mature tree is of an upright shape. I would not cut off the branches until they start getting in the way or become less necessary for the tree's health. Right now they are helping supply food to the roots so the plant can get established. Eventually, there will be more branches and roots, so in a few years these branches will be more expendable.
This is a tree native to wet areas along streams in high desert environments. In its native range, it gets a steady supply of water and it can tolerate both cold weather and drought conditions.
If you planted it where it will get a steady supply of water, it will grow pretty well for its short 30- to 40-year life span. If it doesn't get enough water in the summertime, it will be very susceptible to getting borers, which will require constant spraying to prevent their killing the tree.
Q: Our yucca tree, located in an area of our rock garden, has suddenly had a lot of white creamy looking mushrooms (mold) at the top. The ones protruding from the trunk are hard. They are also spewing out at the trunk's base onto the stones. The base is extremely large (looks like an overgrown elephant hoof) and is soft, crumbly and cracking away.
It suffered damage during the last two hurricanes, which ripped the upper half and all its limbs to the ground. It made a comeback with many new limbs. We do not water more than on the allotted day; however, the rain and heat may not be helping. It is not as healthy looking as it has been in the past years.
Our landscaper suggests waiting until after hurricane season, and he will either cut it down completely, or partially. I would rather take care of it now if that is what I need to do, because I don't want the oozing stuff getting into the stones of my rock garden.
A: As much as I hate to see trees and shrubs removed unnecessarily, sometimes there comes a time when a plant should be removed. No matter how much care and how much expense is given to it, plants don't last forever.
Plants are very resilient. They often survive tornados, hurricanes, floods and other disasters. They might have all their leaves ripped off or they may be split in half, but the roots and remaining stems keep on going. Being able to keep a plant alive is one of the joys of gardening after the hardships of such storms.
How much life-support do you give before you pull out the chain saw? If your landscaper has looked at it and says it should be cut back, I would probably agree. The mushrooms are the final 'flowering' life cycle stage for a fungus. That means the fungus has been growing unseen in the trunk for quite some time. It also means it will be hard to save the plant.
Cutting it down to the ground might not kill it, as it could send out more sprouts that can be used to rebuild the aboveground plant. Cut off all the dead, decaying material and see if there is enough left to try to save. If not, cut it all down and see if anything comes back from the roots. If nothing comes up, then you will have to start over.
Q: Do you have any information on the reason the white oaks in Lemont, Ill., are turning light green, then a yellow green and then dying? There are at least three in the area, two on my property and one across the street that are suffering from whatever it is that causes this.
A: From your brief description, there are several possibilities. When several trees in a general area all exhibit the same symptoms, it often comes from an environmental problem. It could be something simple like too much water from the rains causing damage to the roots. On the other hand, when several trees show the same symptoms, it could be a serious outbreak of a disease or insect problem. In this case, oak wilt is a deadly oak tree disease that needs to be looked at. The causes you list are not specific enough for me to give you a specific answer. Because the trees actually appear to be dying, not just turning color, you need to call your local licensed arborist to get an on-site visit.
E-mail questions to Jeff Rugg at firstname.lastname@example.org.
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