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Sunday, September 20, 2009

Help! My trees are turning brown!!

I really should know better by now. As a Master Gardener, I was trained long ago that conifers (such as pine, spruce and fir...) drop some of their needles on a regular basis. The trees generally don't shed needles every year, as deciduous or leafy trees do. Depending on the species of tree, most conifers usually lose their interior needles every two to five years.

But YIKES! Even knowing all of that, I still did a double-take and caught my breath when I saw one of my thirty-foot Ponderosa pines seem to change overnight. The crew in Tagawa's Nursery Department is hearing the same thing: "Help! My trees are turning brown!"

Tagawa's staff is quick to let these tree-loving folks know that they probably don't need help, and neither do their trees. This type of needle-shed is normal, and most likely there's no reason to use any insecticides or other chemicals. Let's take a closer look.

Like deciduous trees that drop their leaves every fall, healthy conifers put on new growth each year. The tree grows up and out, with clusters of new needles at the tips of the branches. But the trees won't keep these new needles forever.

Take my Ponderosa pine, for example. The needles that have just turned brown are the oldest needles..... three years old, to be exact. That's how often Ponderosas shed. The dying needles are on the inside of the tree, closest to the trunk. These old needles are now shaded out by the newer growth, and quite simply, the tree doesn't need them anymore. So with alarming suddenness, they fade to the color of straw and dry up. The first time we have a strong windstorm, they'll blow off, and the tree will look lush and healthy again.

But the change really does seem to happen overnight, or close to it. And it can be understandably alarming.

So how do you know if your conifer trees are going through a normal fall shed, or have a genuine problem? Here are some things to look for:

*** Normal needle shed will always be on the inside of the tree. It will
discolor those interior needles fairly evenly throughout the tree as
a whole... not just in one part of the tree.

*** Unless the tree has been stressed by drought or other conditions that
could have damaged the roots, normal needle shed will usually occur
in late summer or early fall. Serious stress issues could prompt a tree
to shed its needles earlier. It's the tree's way of calling "uncle" for the

*** If the tree is healthy, the new growth on the tips of the branches should be
supple, green and full, not brittle or discolored.

Trees that have been attacked by the dreaded mountain pine beetle have a different look. These doomed pines (pines only) will often show "pitch tubes" on the trunk.... white or pinkish popcorn-looking areas where the tree has tried to flush out the invading beetle.

Mountain pine beetles fly in late summer. Obvious signs that they've attacked a tree generally won't show up until the next year. I notice the dying trees most often in July, when the summer heat really kicks in and the tree's stored energy finally isn't enough. (It's genuinely amazing how long a sick or damaged tree can look "normal," just running on stored energy. )

A pine beetle attack will often give the entire tree an orangish or reddish cast as it fades and dies. There are ways to protect your most valued pines against this destructive insect. Talk to the folks in Tagawa's Nursery Department or Dick's Corner for details.

But don't mistake a normal late-summer needle shed on your conifers for an invasion of anything harmful. And by all means, don't automatically reach for the insecticide with the mistaken notion that you "just need to spray something." Odds are, you don't.

And remember that with all of our spring rain this year, conifers have put on a lot of new growth. That growth that will most likely have us doing a double-take and catching our breath when it's time for this year's needles to shed a few seasons down the road.

Monday, September 7, 2009

The Trouble with Tomatoes

I knew my tomato crop wasn't doing too well. Out of my twenty-five plants (ya, I know.... about twenty too many....), some crashed by late July. Others kept on trying, but even more of them had given up the ghost by mid-August. But it wasn't until I taught a class for the Douglas County Master Gardeners that I realized how much everyone else seemed to be having problems, too.

I asked the group of fifty or so Master Gardeners how many of them were having a good tomato year. Not one hand went up. NOT ONE!! Now that's a bad tomato season. Let's take a look at what went wrong.

Problem #1: June. Yup, June. Pretty much the entire month of June worked against those of us with home-grown tomato obsessions. June was too wet and too cool for too long. My tomato plants, which were all in the ground before Memorial Day, pouted the entire month of June. Really. They just sat there. They didn't die, but they didn't grow.

Walls-o-Water would have helped protect the plants from the cool June temperatures, but I was lazy and didn't use them. Pre-warming the soil with Walls-o-Water before I planted would have helped, too. Tomatoes (and peppers and eggplant and potatoes....), don't like "cold feet." Warming the soil for several days with the Walls-o-Water is especially helpful in heavy, clay soil that tend to be slow to absorb the sun's warmth in spring.

Kris, Tagawa's Annuals Co-director, is a big fan of Walls-o-Water, and uses them in her foothills garden every spring. She tells me that as of late summer, she still has the Walls-o-Water on her plants. The plastic teepees have collapsed a bit, but her tomato plants are fine. Mine? Not so much.

The most common tomato concern customers are bringing to Tagawa's diagnostic staff at Dick's Corner is something we see every summer. "Blossom end rot" shows up every year, but it's going gangbusters this summer. It's related to our wet June weather, but didn't have to get out of hand the way it has.

Blossom end rot is characterized by a round, brown or beige leathery circle on the blossom end of the tomato.... the bottom of the fruit, opposite the stem. It's caused by a calcium deficiency just as the fruit is forming. Reaching for the fertilizer really isn't the answer. In fact, too much nitrogen can actually contribute to the problem. The best way to avoid blossom end rot is to keep the plant's roots more evenly moist.

We went from a cool, soggy June to a hot, dry July. Good drainage (well-amended soil and raised beds) would have helped with the soggy part of that equation. By the time July rolled around and the soil actually warmed up, mulching the base of the plants with something like straw would have retained more moisture. All of those techniques could have helped to avoid having the plants go from too wet to too dry. My tomatoes grow in raised beds, and I mulch with straw once the weather is reliably warm. And I try not to let the plants dry out. I didn't have a single case of blossom end rot. My tomatoes did have other issues, which I'll explain in a moment.

Blossom end rot isn't contagious. It won't spread from one plant to another. But much of the fruit that was forming at about the same time during the growing season could be effected. Watch for the first signs of blossom end rot while the tomatoes are small. Remove any fruit that shows the tell-tale symptoms, and let the plant's energy go instead toward making healtheir tomatoes.

Make sure you know how moist the soil around your tomato plants (and all plants, for that matter) really is. Poke your finger down a couple of inches, or use a water meter. Either way, when the top two to three inches of soil has dried out, water thoroughly, but don't over-water. Apply enough water to soak down to the bottom of the plant's rootball. And take it easy with the nitrogen, the first number on the fertilizer package. Nitrogen will promote lots of leafy growth. All that foliage could "steal" some of the calcium that the fruit needs more.

So what went wrong with my own plants, if they managed to escape the blossom end rot that's plaguing so many others? Why did the lower leaves turn yellow so quickly? Why did entire sections of certain plants just call it a day? Quite honestly, I think I set them up for failure. I planted earlier than I normally do, (and felt pretty proud of myself at the time....) I didn't pre-warm the soil. I didn't use Walls-o-Water or any other protection to help buffer the plants from cool temperatures that are always possible in June. And despite my best efforts over the years, including gardening in raised beds, clay soil is still clay soil. In short: I didn't anticipate potential problems from Mother Nature. Silly me.

Okay. Lesson learned. My 2010 tomato crop is already taking shape in my mind. Next year will be different!