HG: Homegrown Column February 21, 2009

For several years, we’ve had our pinyon pine trees sprayed for prevention of beetles. Last summer, because the technician who did the spraying told me we didn’t need to spray, I stopped the service. In the fall, I noticed a couple of dead branches on one of the trees. I’m wondering what may have caused this damage, and what I should do now?
I want you to know I enjoy Homegrown in the Daily Sentinel a lot.
Any help would be much appreciated. Thank you.
— Judy

Actually, I’m a bit torn as to what to recommend to people about preventative spraying for the ips bark beetle in pinyon that gave us so much trouble four or five years ago.

That epidemic was brought on by the drought we were in at the time, which put our native pinyons under stress and that stress made them susceptible to the ips beetle.

We’re pretty much over that drought cycle and the native pinyons have pretty well recovered.

So do we need to keep on spraying?

I guess it depends on how much of a gambler you are and how confident you are about the health and vigor of your trees.

Stress on the tree is an absolutely essential prerequisite for beetle attack, so if the trees are well cared for (as I’m sure yours are) and they seem to be growing well and are free of any potential stress, you might take the chance and let them go.

However, if they seem to be struggling a bit, are newly planted or even if you’re not willing to take the chance, there’s nothing wrong with exercising a little “preventative medicine” and to continue with your spraying.

Now, that’s the story about ips beetle, but I’ve got a feeling that there may be another critter troubling your trees.

A second beetle called the pinyon twig beetle attacks the newest growth of the tree. This is a teeny little insect (the larva are about as long as the width of a pine needle) that tunnels under the bark of pinyon pine.

Historically, their damage has been limited to the very tips of the twigs, say the growth from the last year or two. This damage is really no threat to the overall health and survival of the tree (unlike ips beetle). It’s more of an aesthetic issue, making the tree look a bit bad.

However, the past several years I’ve seen instances where pinyon twig beetle damaged or killed off larger, even significant branches of a tree.

Besides the obvious effect on the tree’s appearance, the loss of significant growth can place the tree under stress, giving the ips beetle an opening, which is a much more serious problem.

The spray schedule for pinyon twig beetle is the same for ips beetle: Three sprays a year with 38 percent permethrin.

The first one goes on about the first of April, again about the first of July and a final one about the first of October. The way we’ve done these sprays is to spray inside the tree, concentrating on soaking the bark of the trunk and the main branches where ips beetle typically attacks.

To control pinyon twig beetle, do the spray for ips then take a couple of steps back and thoroughly spray the entire tree, soaking all of the branches out to the tips.

One last thing. If those dead branches are still there, prune them off right away and put them in the trash.

I’ve been reading about the hedge maple (acer campestre). From what I’ve read, this seems like a perfect tree for the Grand Junction area. When I’ve asked about it in local nurseries they don’t seem to know about them or know very little. No one stocks the hedge maple.
So what is it about the hedge maple? A medium-sized tree, Zones 4–8, drought tolerant ... what’s not to love?
I can only assume there is a reason no one carries this tree. Can you enlighten me?
Thank you.
— Ginger

Actually, I don’t have a good reason for why that is. Probably more of institutional “inertia” where the nurseries carry the plants they always have because those are the plants we’ve always carried.

I know that’s not much of an excuse.

Hedge maple isn’t all that common in the nursery trade. However, one alternative you might consider is tatarian maple. There’s a new variety called Hot Wings.

It’s small like hedge maple and its close relative, amur maple, but it’s much more tolerant of drought, our hot, dry climate and alkaline soils.

The really cool thing about this tree is its seed. Maples form a winged seed called a samara.

The papery wings of this variety are a bright fire engine red.

I’ve seen these trees in the middle of summer and thought the tree was full of beautiful red flowers. It’s really a showy tree.

Anyway, thought I should mention it.

Dennis Hill is the nursery manager at Bookcliff Gardens, online at http://www.bookcliffgardens.com. Send questions to Bookcliff Gardens, 755 26 Road, Grand Junction 81506; or e-mail .(JavaScript must be enabled to view this email address).


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