The Complete Guide to Landscape Design, Renovation, and Maintenance
by Cass Turnbull

WEEDS: HAND TO HAND COMBAT

Weeds, weeds, weeds! I love some of their names. They sound so much like the ingredients in the witches' brew or the lady of the castle's sachet:

I am not as amused by the colorful names of more familiar weeds in my region-horsetail, morning glory, chickweed, fireweed, shot weed, and nightshade. Weeds vary in species according to climate, zone, and geographical area. But all weeds of all areas share one or more familiar strategies to overcome your yard. When you understand their plans, you can best choose your tactics and tools.

Most weeds are one of three types: annual, herbaceous perennial, or woody perennial.

Annual Weeds
Many annual weeds are small plants in such large numbers that they form a mat like chickweed or shot weed. Others can grow quite tall-pigweed, lamb's quarters, and prickly lettuce. These annuals have shallow roots and are generally easy to pull or hoe out of the ground. But watch out! These easy weeds make up for their puniness by reproducing quickly. I schedule my visits to clients' yards for once a month, because this is all the time it takes for these tiny villains to germinate, grow up, set flowers, and-egad-go to seed! And watch the seeds, for

one plant can number its seeds in the hundreds, some even in the many thousands! For example, pigweed numbers 117,400 seeds to a plant and Shepherd's purse, 36,000 seeds to a plant: each one a potential new plant to plague you next month. The new homeowner or yard owner is often gratified after weeding the garden plot just outside the front door, because it was so painless and looks so clean. The same owner is discouraged to find the exact same mat of thick weeds reappear in but one month's time. Using chemical contact sprays like Roundup (glyphosate) to try to control annuals is silly. Seedlings will soon replace their dead parents. Besides, it's like using a chain saw to cut butter.


Using Mulch To Control Weeds
The cure? Mulch. Mulch is both a verb and a noun. One mulches with mulch. When you mulch, you are covering the soil with a layer of material. This material–called mulch–can be rocks, peanut shells, straw, shredded newspapers, bark, sawdust, leaves, you name it. You use mulch to smother germinating weed seeds or keep them from "seeing" daylight and thus prevent germination.

My clients think of me as a steer manure compost junkie. The mulch I use is made of one-third steer manure and two-thirds sawdust composted for eight months. The fact that it is "hot-composted" means that any weed seeds it may have contained have been destroyed.

There are things you should know about mulch. It helps your soil retain water, but it takes extra irrigation to get the water down to the soil. Often times the homeowner will water the mulched beds for fifteen minutes to an hour-it looks good and wet, but wait, the shrubs are wilting. You must water a lot longer to get that water down to the plants' roots.

To be sure, dig down with your finger. Is the soil moist at the roots? If the answer is yes, then you have watered enough.

Not only does mulch retain water, smother tiny weeds and weed seeds, and make it easy to pull new weeds, it is also harder for new wind-borne weed seeds to get a foothold.

Mulch can be spread anywhere from 1 inch to 4 inches thick. The thicker it is, the more effective and longer lasting. Spread it thick in big empty spaces. Spread it thin around the root zones of shrubs to allow for sufficient air exchange, especially around shallow-rooted plants like azaleas and rhododendrons. And never let mulch stay mounded up in the base or the "crown" of a plant. It can cause crown rot on some shrubs and can kill them, even a year or more later.

Use the back of your fan rake and sometimes your feet to spread mulch out. Rake back and forth to get it nice and smooth and level. Then do the next load. After a while you will be able to tell how far apart to put your wheelbarrow loads. Be sure to go back and check to see that mulch is not smothering the crowns of shrubs or trees. Push the mulch away from the base of the plants with your gloved hand.

Speaking of the gloved hand-one of the advantages to using sawdust-based products instead of bark (besides looking better) is that when you spread it or weed it you don't come away with a handful of tiny slivers. These painful microscopic slivers found in bark will even get into your gloves to plague you later when you're not working in the beds.

The bigger the pieces of your mulch, the more effective it is, and the slower it is to decompose and disappear. Smaller particles look nicer, however. Composted manure mix is very fine-it looks like good, dark garden soil. And since gardens are for looks, I use it and just apply it more often. Finer mulches can also be used around tiny plants like flowers, where large-particled bark will not work well. The smaller the plant, the thinner the layer of mulch should be.

Fine particled mulches can sometimes develop a hard crust on top that repels water. To get water back down to the roots, fluff the mulch up with a hoe or hand cultivator and rake it flat again.

Mulches, especially ones containing wood products like sawdust, will rob the soil of nitrogen as they decompose, so it's wise to fertilize with nitrogen, especially on newer plantings.

Depending on the type and thickness of mulch, you can expect to reapply it once every two to six years. I generally do a little spot section in the yard every year to keep up on it and avoid having to do a big project.

Mulch will work to smother seeds, and if perhaps you left the carcasses of some hoed-up annual weeds behind, the mulch is usually enough to keep them down. It will not, however, keep your perennial-type weeds down if you haven't gotten rid of them roots and all. Those dandelions and grass will just grow taller to find their place in the sun. And they will be harder to dig out after they've been mulched over.

Weed Seeds And Flowers
Recently I was quite distraught with the irrigationist at a client's home. I spent the winter weeding and carefully mulching every square inch of barren ground, including the 2-inch strips between the concrete paths and the edged grass. The irrigationist laid new pipe and very carefully eliminated the extra soil by spreading it over my mulched strips, thus infecting the area with newly uncovered weed seeds. ARRGH! I'm sure he thought me quite crazy to kick up such a fuss.

Weed seeds themselves are by definition incredibly tough. They can lie dormant under the soil for years, until you inadvertently dig them up, to plant new shrubs or perennials and then, in classic horror story fashion, they come alive. Weed seeds have been known to stay viable for decades. Some seeds frozen for millennia in glaciers have been found viable!

Match the tool to the weed type. Annuals can be knocked down with a garden hoe and raked out. Perennial weeds must have roots dug out either with a hand cultivator or a dandelion weeder. Some tenacious tree and shrub seedlings can be pulled out with pliers

If you catch annual weeds before they flower, you can sometimes kill them by hoeing or chopping off the tops, or knocking them out of the soil with your hand cultivator. They will dry out (desiccate) and die on a nice sunny day. But if you have automatic irrigation, or if it rains, they can, and do, sink their roots in again and head back up in a day. And the bad news continues, for both annual and perennial weeds. If they have set up flowers, many have the capacity to turn their flowers into seeds after they have been uprooted and are basically dead. That dandelion flower head you snapped off when it was but a yellow flower had better go into your pocket because if you drop it, it will turn into a thousand fluffy seeds that float across the lawn and start anew. Professional gardeners always watch weeds out of the comers of their eyes. Their anxiety level rises sharply as the weeds go into flower, and they begin to twitch at the sight of ripening seed heads.

Hoe during dry weather; dig or pull out weeds after a rain. Moist ground gives up plant roots with much greater ease. You may choose to water your shrub beds deeply the day before to ease your weeding chores today.

But really, annual weeds are easy. Hoe them down and rake them out, then mulch. Catch the new little guys before they go to seed, and the population will stay in abeyance.

Perennial Weeds
Tougher to control are perennial weeds. Perennial weeds, like morning glory (bindweed) or horsetail, often die back in the winter and the roots stay alive underground. Others stay green all winter, like grass and dandelion. To eradicate these you will need to get their roots out. Roots come in several types: fibrous, creeping, and tap-rooted. A fibrous-rooted

weed has a matted clump of roots-like a grass clump, or a clump of clover. Some plant roots hold on tighter than others. Loosen the soil with your hand cultivator, or for bigger jobs with your spading fork, to get out as much root as possible. Jam your spading fork into the ground and rock it back and forth. Do this several times until the plant gives up easily and comes out with all its roots. If you just yank off the tops, the plant will simply regrow from the roots below.

More dangerous yet are tap-rooted weeds like dandelions. Their roots are like a carrot's-and go straight down. Use the knife-like dandelion weeder for these in order to dig straight down and pry them out-deep down. If you do not take the extra time and effort to do this, you are simply wasting your time, as these plants grow back lickety split from tiny bits of root left. If you can't get all the root, get as much as you can, in order to start starving the weed.

Dressed for hand-to-hand combat.

A truly accomplished weeder knows how fast to go and how much time to spend on each type of weed for the best kill-per-minute-spent ratio. He or she may whiz through a patch of annual weeds like chickweed but slowly dig out a fair amount of the roots of a perennial dandelion, red clover, or horsetail.

Speaking of horsetail, many plants have the added strategy of "rubber" roots. You discover that as you pull they simply snap off leaving enough root behind to rise again. Horsetail and morning glory fit into this group. Many of these you must control using sheer tenacity and vigilance. Dig down with your dandelion weeder and get some below-ground root of horsetail. An inch or two will make a significant difference in its ability to regrow. It does come back, but slower and smaller than before. Doing this also starves them out by never letting leaves show long enough to manufacture food from sunshine. Eventually, you find that you are winning the battle, though it may never be won.

Morning glory and some grasses and various other plants also fit in the category of weeds that have stems or roots that creep along just under or above the surface soil. They send up new plants every so often. These plant structures are called, variously, stolons or runners and rhizomes or creeping roots. (These modified plant structures can send up new plants every so often or, when broken up, say with a rototiller, each piece may become a new plant.) Morning glory and horsetail roots have been known to run 30 feet underground before re-emerging perhaps on the other side of the concrete road. You can chase these roots as far as you dare, though you will find total eradication is difficult as they break off and disappear under concrete pads and rocks, leaving a nest of hiding roots to creep back out later. Curses!

Mulch will help you check growth of the runners. In clay soil it is nearly impossible to pull up runners, as they will break off. But in nice, soft mulch they simply lift out with a light tug. For horsetail and morning glory, I sometimes resort to judicious use of herbicides. More on them later.

Perennial Woody Weeds
The third type of weed is a perennial woody plant. That means that it is brown-stemmed, not green and supple. It's woody and tough like a tree or shrub. These are often trees or shrubs that "volunteered" in your yard. That means that no person planted them. Birds that eat berries often deposit pre-fertilized seed packets in your yard. Common woody weeds in my area include holly, cotoneaster, blackberry, laurel, and hawthorn.

I also include wild clematis vines and various unwanted trees such as maple, mountain ash, Douglas fir, alder, and willow. You can dig these out using a shovel and mattock or, as discussed in a previous chapter, you can cut and paint the stumps of these and other woody brush with glyphosate (Roundup). Look up the cut stump treatment instructions on your Roundup label. It says, "Apply a 50 to 100 percent solution of this product to the freshly cut surface immediately after cutting." Delays reduce performance. Don't get dirt in the container or on the brush. This also reduces efficacy. I use an old rubber cement jar, having cleaned it out with rubber cement remover. It has a built-in brush and fits nicely into a tool belt pouch I wear. The tool belt also holds my dandelion weeder and my claw-like hand cultivator.

I find I worry less about using herbicide this way than by spraying an entire berry-laden bush in which some child or animal may care to forage. And I get better results. With blackberries, say growing out of a patch of wanted ivy groundcover, I carefully cut the cane about 3 inches above ivy level. I leave my red handled clippers lying over the blackberry cane stump to mark it as I reach for my jar and brush to paint the cut stem. If you don't leave a marker, you surely will lose track of your victim once you turn your eyes away. Carefully recap your brush killer, pick up your clippers, and move on. This is painstaking and time-consuming work, but it beats cutting down the same blackberry patch or cotoneaster bush ten years in a row. The cut-and-paint method of brush control is most effective in late summer and in fall. Cut stump treatments, with Roundup or another herbicide labeled for that use, generally mean less chance of problems due to drift and overspray to desirable plants. When applied carefully there is also less chance of surface and ground water problems. Be absolutely certain to wear gloves and eye protection when working with herbicides as a cut stump treatment. Be sure to return your brush killer to a proper storage container at the end of the day, as it is illegal to store herbicides in other than their labeled containers.

Smart weeds hide under and inside shrubs. Train yourself to search for them. Look for any variation in leaf type, texture, or color. Search and destroy.

Smart Weeds
There are some other weed control strategies of which you should be aware. As you can see from the earlier list of plant names, there is a weed called smartweed. Personally, I think they are all pretty "smart" and, of course, tough. But the smartest weeds are the ones that hide inside your ornamental plants and groundcovers. These are the ones you are likely to miss when going through your yard. I have trained myself to peek under and inside all shrubs to see if there lurks the would-be parent of a whole new generation of weeds. These smart weeds can be difficult to dig out because their roots are entwined with your shrubs. Do whatever it takes, using dandelion weeder or fork to get as much out as possible.

Even if it means sacrificing some roots on your shrub, get that weed out! As a pruner and as a weeder I have also trained my eye to pick up any and all variations of leaf type in a given setting. As practice, you should stare at yours or a neighbor's group of low shrubs and-like a kid's game- spot the leaves that don't fit. Amongst the small rounded

leaves of the evergreen azalea, find a big heartshaped morning glory. In a spirea with many tiny leaves, find a long, narrow fireweed. Look for the telltale shiny dark green leaves of a volunteer laurel or holly, or the grayish leaf of a cotoneaster. Searchand-destroy is the name of the game. An especially tricky one is fireweed, which looks remarkably like phlox out of bloom-only the reddish stem gives it away. Don't be fooled by smart weeds.

Pretty Weeds
And don't be suckered by pretty weeds. Many of these are wildflowers out of place. Although charming in the woods and fields, they can be a detriment to your garden. Or maybe not. Many of these are weeds by definition only. In one yard a client may curse the wild, stinky geraniums. Other clients may ask me to transplant some to a new area, they like them so much.

A list of "wildflower" type weeds in my area that I would eradicate:

A list of sometimes okay, sometimes not:

Most of these are weeds by definition because of their vigorous growth habit. A few may be considered among the Great Weeds.

Great Weeds
The Great Weeds are the ones that have a reputation for utterly destroying gardens and defeating gardeners. I would put on this list some types of bamboo (running), horsetail, false bamboo, blackberry, morning glory (bindweed), and wild clematis. Your area may have others on the "most wanted" list, including loosestrife, witchweed, kudzu, and nutsedge. Check with your local extension agent for help. Be vigilant and thorough with the great weeds. It is with these weeds that I most often resort to chemical warfare, though I have seen all of them beaten in hand-to-hand combat-it just takes a lot longer.

Weed Control Errors
Common weed control errors that people make are: trying to deprive weeds to death by withholding water or fertilizer; and limbing-up shrubs to make it easy to get to the weeds.

In the first instance you will merely give weeds the competitive edge over your shrubs and groundcovers. Weeds are-again by definition-able to withstand extremes of heat and drought better than your desirable ornamentals. Prostrate knotweed growing in the crack in the sidewalk is known to withstand temperatures in excess of a hundred degrees. You must intervene to keep the weed population down, while watering and fertilizing your groundcovers and shrubs long enough to give them the competitive edge.

There exists a common misunderstanding that your newly planted groundcover will somehow choke out the weeds that are taking foothold. Impossible! You must-in those first years of establishing a new garden-keep your area pristine and weed-free until such time as the groundcover is so thick that the new seeds blowing in from the lot next door land on leaves, not soil, or if they find their way to the soil, the leaf cover is so thick that the light is insufficient for them to germinate.

Shade
This is the error in raising the limbs of your shrubs to make weeding under them easier. It simply lets in more light and enables weed seeds to germinate. Shade is one of the best strategies of the good gardener. It keeps seeds from germinating and slows down the growth of those that do. Bare, clean beds can look nice, but for low maintenance fill all those spaces with healthy, vigorous trees, shrubs, and groundcovers.

Strategy
When tackling a yard overrun with weeds, first clean up a small section-we'll call it section A. Next time (next week or next month) re-weed A, then clear out a new patch B. Next time re-weed A and B and clear out new section C. Get the idea? When you are finally done you have a yard that is totally controlled instead of looking back to find A re-engulfed in shotweed.

SUMMARY

Strategies for dealing with weeds

Annual		puny but reproduce fast easy to hand weed or hoe out mulch to smother seeds vigilant removal of potential parents before they set seed
Perennial		use proper tools to dig them out mulch repeatedly cut off tops to starve hunt hidden, would-be parents
Woody brush and weedy trees		dig out roots; use stump grinder for trees cut-and-paint with herbicides registered for such use shade mulch

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