Verticillium typically fatal when it comes to maple trees

I’m sending you a photo of a maple tree that is located in Battlement Mesa and was planted almost 20 years ago. For many years it had red leaves, but the last two years, and especially this year, they are a lime green color. It was also supposed to be a small tree but it is huge. Any suggestions? One limb appears to be dead or very unhappy. I am writing this email for the owner, a 90-year-old lady. Any advice would be appreciated.

— Karol

It looks like your friend has a Silver Maple or a hybrid of it. As you’ve seen, these are big shade trees.

My wife and I have a 35-year-old one at home that’s huge. It’s fairly typical for maples to show some yellowing, especially in the summer. This is mostly a result of the soils we have in western Colorado and can be remedied with an application of a Chelated Iron Fertilizer plus some nitrogen.

However, I’m a bit concerned about the tree. I can’t tell for sure, but it looks like there is some dieback. This is often an indicator of a fungal disease called verticillium. This disease enters the tree through the roots and travels through the vascular system of the tree.

As it progresses, it clogs up the vascular tissue, slowly choking the tree off.

The typical pattern is for a portion of the tree to show some leaf yellowing. Next year, it’s a bigger area with perhaps some small twiggy die-back. The next year, it’s bigger with larger branches starting to die off. It progresses from there until the tree is dead. Sometimes it moves fairly quickly and other times more slowly.

What’s indicative of it is this gradual eroding away of the tree from year to year.

Unfortunately, there is no treatment for the disease and it almost always fatal. The great big Silver Maple in our yard has it. I’ve been watching for it for several years and about five years ago I noticed a yellowish patch on the back side of the tree. Over the next several years it’s spread to a good third of the tree.

I’ll lose the tree, I know. I’m just hanging onto it until it starts looking really bad. I’m having it pruned occasionally to remove any hazardous dead branches.

Wish I had better news for you.

How do I stop a willow hybrid tree from blooming and dropping its blooms and then its berries?

— JoAnna

Are you sure what you have is a willow? Willows do bloom (it’s usually greenish yellow and small and inconspicuous) but they don’t set a berry.

If it’s something else, the only thing I can recommend is a product called florel. It’s used to keep fruit from setting on trees. It won’t stop the flowers, but that’s usually not the biggest problem for folks.

You spray it on when the plant is in full bloom and then repeat it two weeks later. It’s not perfect. Some years it’ll eliminate 98 percent of the fruit, and other years you wonder if it did anything at all, but it does help.

Dennis Hill is the nursery manager at Bookcliff Gardens, Send questions to Bookcliff Gardens, 755 26 Road, Grand Junction 81506; or email .(JavaScript must be enabled to view this email address).


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