The first day of school usually ushers in nurserymen’s harvests of early fall crops. So, watch for the dusty millers and luscious snapdragons and dianthus that are the openers of this ‘tidal wave’ of autumn beauties. Their eye-catching colors are impossible to miss!

This also is the time to find the best aspens. The narrow form of an aspen tree is useful in small spaces to create screens or for defining property lines and driveways. Aspens are considered to be “family oriented” as they prefer to grow in clusters of 3-5 trees. Their waxy heart-shaped leaves are green in summer, turning to brilliant shades of Arizona gold in autumn. The first fall crops are in garden centers now, preferring to be planted during our monsoon season.

There are two ways to harvest aspens. The first is to dig them by hand from someone’s ranch. These trees are wild looking, very tall, and have a well-defined white bark marked with black knots. Many times the roots are too small for the size of the tree, which often results in an unsuccessful transplant.

I prefer the other type of aspens, the farm raised varieties; they’re more desirable because of their perfect shapes. Each cluster is primped and groomed for uniformity. The trunks will not be as mature and white as their ranch-style cousins, but because aspens grow so fast the trunks will lighten and bulk up quickly. Best of all, the fully formed root structure means almost no transplant shock from a farmed aspen.

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Now let’s talk weed extermination. Which weed killer is the one for you? So many different products make for uncertainty, trepidation, and utter confusion. Which is the right brand? Is it best to go with a concentrate, a ready-to-use, a hose-end applicator or a tank sprayer? If you already have sprayed the unwanted growths only to find they return with a vengeance, is it any wonder that the summer marketing campaigns of Ortho, Roundup, and Specticide are confusing? Actually, weed killing is easier than it appears to be.

First, stay away from soil sterilizers, also known as soil killers. These products are so dangerous that I’ve stopped selling them at our garden center. While they do provide season long weed destruction, these liquid products are labeled ‘vegetation killer’ and ‘ground clear’ for good reason.

The problem with a soil killer is that the product migrates through soil very easily, especially in a monsoon storm. Absolutely nothing growing in the migratory path will survive. I’ve seen too many mountain mistakes made with these soil sterilizers, including the killing of neighbors’ trees growing next to the dry wash below where the product was used. This is why they are referred to as soil killers. Stay away from these products!

A foliar spray is the best means of killing weeds. If these liquid products touch the soil it doesn’t matter because the product is absorbed only through the leaves. There are two types of foliar sprays for weeds. One kills everything it touches; the other kills everything but grasses.

Roundup’s long time success as a weed killer was because it made use of glyphosates, which kill broad-leaf weeds and grasses. Now that Roundup’s patent exclusivity has expired, cheaper generic brands are available, many that work as well if not better than the original. The strongest concentrate on the market is a mixture of 41% glyphosate; that is the strength to buy. I prefer the product produced by Bonide, aptly named KleenUp. Because it kills grasses and broad-leaf weeds, great care must be taken when using it! At our high elevations glyphosates only work in summer heat, so just buy the amount needed to take care of weeds through the end of October. After our first frost this weed killer is ineffective.

My favorite weed killer is Weed Beater Ultra, a foliar spray that kills everything but grasses. It’s designed for lawn use, but I find it is equally effective in wilder spaces where it will kill tumble weeds, horehound, and goat head type weeds while leaving wild grasses unscathed.

When treated with Weed Beater Ultra, softer weeds experience meltdown within a day; tougher weeds are dead by week’s end. Sprayed soil is not tainted, so planting and over seeding can begin the next day. This is one of the few products that work in spring, summer, fall, and into the early parts of a mountain winter.

Tip #1 The more leaves on the weed to be decimated, the better the kill rate. The biggest blunder is spraying weeds right after they have been cut back.

Tip #2 Many local weeds have waxy, furry, or fuzzy leaves for protection from sun damage. Unfortunately, these natural mechanisms make them difficult to kill; so, whatever type of weed killer is used, it must be used with Spreader Sticker. When using a tank sprayer combine equal amounts of Spreader Sticker and weed killer and spray on leaves until they are dripping wet. For hose-end application, first apply spreader sticker through the sprayer then immediately spray on the weed killer. Your weed knockout effectiveness will double with this insider’s trick.

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If you like personalized gardening classes with lots of Q & A, join us at the garden center every Saturday morning at 9:30. The classes are free but they are informative and fun, just ask any of the many gardeners who regularly attend. Check out the entire schedule of class topics on my website at www.wattersonline.com/classes.php. Today’s class is entitled “Gardening in the High Country”; it offers lots of tips, tricks, and techniques that make local gardening easier.

Ken Lain, “my personal mission is to help local homeowners garden smarter and get our local garden timing right.” Throughout the week Ken can be found at Watters Garden Center located at 1815 W. Iron Springs Rd, Prescott, or may be contacted through his web site at www.wattersonline.com

Until next week, I’ll see you in the garden center.