The Weekly Weeder: Natural Weed Control

Notice the old leaves under the rose, and the 4 x 8 sand paths.

            Weeds are taking over neglected portions of our cities and countryside, making them ugly, disorderly and unsafe.  Flowering weeds are often ugly, always disorderly, and once they dry out, they are a fire hazard.  If not killed before going to seed, they spread themselves around; they are a nuisance that multiplies.  Whole city subdivisions have burned in recent decades, and some small towns as well. When weed codes are well enforced and properties are watered, cities don’t burn. 

          The most dangerous weeds are annuals and biennials that seed and dry out in a season.  They make many seeds, some of which can last for years in soil before they sprout or rot.  But their roots don’t need to be pulled to kill them.  All their top growth comes from their crowns, the part of the plant between the roots and the stems.  Cut them under their crowns or pull them when they are flowering before they go to seed and they are gone, but it can take years to control the seeds already in the ground

          You can cut them under their crowns with scissors or a knife, which is great for going after individual weeds, but is relatively slow.  Still, this is the best way to handle seeded puncture vine, a noxious weed that pops bike tires as well as sticking shoes and bare feet.  Cutting under crowns or pulling are the only ways to take weeds out selectively in lawns, beds and borders.

          You can also beat the crowns out of the soil wholesale with a string trimmer.  This works best when the plants are young and not yet seeded, and the soil is relatively soft.  It has to be repeated to catch newly sprouted annuals and re-growing perennials.  Done often and long enough, it can kill out perennials as well.  It is rather messy.  A hula hoe (AKA scuffle hoe and stirrup hoe) doesn’t throw stuff around.

          You can mulch with leaves, compost, wood chips or bark to smother small plants and stop seeds from sprouting.  Most very small seeds need a touch of sunlight to sprout, and nearly every newly sprouted plant can be easily smothered with 2 inches or more of dense mulch.  Avoid fine bark and bagged bark with fines; bark’s natural preservatives leach downward and kill soil life, but not plants. Larger barks do not kill soil, but ¾” bark and walk-on fir are dense enough at 2” deep.  Walk-on fir bark is most effective at staying put; ¾” floats away on slopes.

          Leaves are the most effective mulch, though some tend to blow around.  Leaves that last for a year, like oak and red maple, are most effective.  They dry quickly on the surface and make a lousy seed bed for whatever falls on them.  Leaves and compost also feed soil life, which makes the soil soft for pulling weeds and provides habitat for good (predator) bugs.

          Perennial weeds like blackberries can also be fire hazards and nuisances.  Cutting under or pulling their crowns is effective, but birds drop seeds in their droppings.  When it comes to weeding, constant vigilance and watering is the key.

 

Revised 12/10/2024.  Published at GardenGrantsPass.blogspot.com

           

          Rycke Brown, Natural Gardener          541-955-9040        rycke@gardener.com

The Natural Gardener: Leaves build soil and stop weeds

Leaves are not waste and should not be wasted.  They are the best and cheapest mulch around for stopping weeds, building soil and providing food and habitat for predator bugs.  This retired Natural Gardener used to haul bags of excess leaves away for free to customers through the fall, spreading them to reduce work and help preferred plants grow for the rest of the year.  Now I am taking leaves for my own yard only. I prefer leaves in clear plastic bags.  I don’t take bags heavier than 50 pounds, or with too many sticks.

Nearly every other mulch is a seedbed as soon as it is spread.  Seeds fall on top, find a crevice and grow.  Leaves dry out on top, and so make a lousy seed bed for anything that falls on top of them.  Even a thin layer stops small seeds beneath them that need sun to sprout.  Two inches or more can smother most seeds as well as small plants and feed the soil enough to soften it and make it easier to pull the weeds that grow. 

The deeper they are laid, the more weeds they can stop and the more they build the soil and soften it.  A foot or more will grow huge vegetables, while they rot and worms and pill bugs eat them over the course of the gardening year.  That increased fertility can be maintained with only a few inches per year. 

The only thing comparable to leaves for building soil is compost, which leaves become without any special help, if they aren’t mounded.  A mound sheds water, within which leaves can stay dry and not decompose for years.  Spread flat, a foot of leaves is the equivalent of 6 inches of compost, which can also grow huge vegetables, plus can be used to build beds year-round.  In late spring and summer, exposed compost also dries out quickly, but in winter, it is a seed bed for whatever falls on it. 

You can start small cool-weather seeds by spreading an inch of compost on top of leaves and scattering the seeds in it; for larger seeds in late spring and summer, scatter seeds on the leaves and cover them with compost.  You can also poke large seeds like peas, corn, beans and squash into the leaves to where it is moist to maintain that cover of dry leaves while they grow.  You can plant starts into leaves as well, with or without compost on top.  

You can warm the leaves to help the seeds and starts grow faster by putting rocks around them.  Rounded river rocks, just small enough to move with one hand, are easy to move and hold heat through the night, when the plants need it most.  The smaller the rocks, the hotter they get but the less heat they hold through the night.  Larger rocks can be used to provide a solid edge for mulch beds and keep them from spreading.

Leaves should be removed from buildings, pavements, gravel, and paths.  They should be left and built up on open ground, in beds and borders, and mulch-mowed into lawns.  If you have too many, put your excess in clear bags and call me.

Gardening is easy if you do it naturally.  Litter is tagging, marking the territory of the disorderly.

Rycke Brown, Natural Gardener      541-955-9040             rycke@gardener.com

Weekly Weeder: Start stopping spring weeds now

Groundsel has yellow, nodding flowers and bitter cress has tiny white, erect flowers.

          Fall has barely started, but spring weeds are already growing.  Now through spring is the best time to kill them.  Cheat, foxtail, heron’s bill, groundsel, bitter cress, cleavers and many others can most easily be killed in the months before they start blooming.  The earlier you get to them, the easier it is.

Heron's Bill, starting to bloom in the spring.  It takes a lot of mulch to smother it at this point.

          You can kill them three ways: by smothering with mulch, preferably leaves; by pulling them out; or by cutting them below the crown, the point from which roots and leaves grow.

          Smothering with mulch saves you the most work in the long run, in the places where you can mulch.  Leaves, when spread 2” or more deep, can stop weeds that haven’t even started yet and those too small or too crowded to be worth individual attention.  Tiny seedlings can grow through a few layers of light fluffy weeds, but more than that can make them run out of food before they find the light.  Blocking sunlight on soil can stop seeds that need sun on soil from sprouting at all.  And leaves make a lousy seed bed for seeds that fall on top of them because they dry out quickly.

Leaves covered with pine needles, which hold them in place.

          But not all leaves are created equal.  Some are eaten by worms before fall is even over, some by spring, some stick around until midsummer, and some have to lie around decomposing for a year before even crazy snake worms will touch them.  (If you have no soil life because fine bark has killed it all, it may take a year or more for even soft leaves to go away, but that’s a subject for another column.) 

Fallen red maple leaves stopping groundsel and other weeds 

          Hard leaves, like oak, sycamore, sweet gum and magnolia, tend to be stiff and fluffy and take a few more layers to stop weeds from growing through.  Many medium and soft leaves lie flat and can stop weeds from sprouting with only a single layer, but will be gone before summer weed seeds start flying.   A mix of hard and soft leaves 2 inches or more deep will stop most small seeds and plants from growing, and feed and soften the soil to easily pull the ones that get through.  2 inches of leaves in the fall is enough to keep flowers and shrubs fed and happy, with loose, easy-to-weed soil that is protected from rain and sun.

A foot or more of leaves will grow big vegetables as they decompose.  For small seeds, spread an inch of compost on top and plant on it.  Large seeds and starts can be planted into the leaves without compost, allowing the leaves to stop weeds from sprouting on top. 

Cheat, blooming en masse, at the point when the roots are shrinking and it is again fairly easy to pull.

Annual grasses, large and small, are most easily pulled from 3 to 6 inches tall.  The longer they grow, the more roots they hold the soil with and the harder they are to pull.  Annuals cheat and foxtail are a lighter green and have a softer texture than perennial grasses, are often fuzzy, and grow in clumps, without runner roots.  As they send up seed stalks in the spring, they use up their roots and are more easily pulled, but time is then short to pull them all.

Most taproots are more easily pulled when the ground is wet, but some in rocky or very hard soil, or with soft stems, won’t pull and must be cut under the crowns.  This will stop most annual weeds and many perennials, but some perennial taproots, like dandelion, dock, and creeping oxalis, need the soil to be loosened with a tool and pulled eventually.  Some, like oriental poppies, can grow back from a root tip deep in the soil and take several years to get rid of completely.

                             

Rycke Brown, Natural Gardener          541-955-9040        rycke@gardener.com

The Weekly Weeder: Chickweed for fall and winter food

          Fall is in a hurry this year, sending us cold, rainy weather on the equinox, and now a summer-ending rain system as October began.  It may warm up to the 80s this weekend, but maybe not, and it will probably be the last such warm spell until spring.  We are forecast to have a cold, snowy winter.

Chickweed en masse under locust trees by the Greenwood overlook.  This area got fenced in this year, but there is more not fenced further down the trail, where the city spread compost a few years ago.

          Chickweed has been growing in my watered garden for weeks.  Now that the rains have started in earnest, it will be sprouting in the dry areas down by the river, where it grows thick and lush, under the locust trees along the river trail behind the waste water treatment plant on Greenwood.  Locust drop small, soft leaves that chickweed can grow right through and they form rich soil to grow chickweed leaves up to an inch long and a half-inch wide, large and juicy enough for good salad, sandwich and boiled greens right up until they seed out heavily in the spring.  

The stems are soft and juicy and can be eaten along with the leaves.   I like to cut just the top two inches of the plant for eating, for minimum stem and best quality.

They often start flowering in late fall with small, multi-petalled starry white flowers which quickly make tiny seeds, but are still good eating until the weather warms in the spring and they get leggy with smaller leaves and lots of seed.  Their taste is mild and very green.

Chickweed being weedy on the Caveman Bridge a few years ago, growing in decomposed locust leaves.

When it gets too leggy and seedy for salads and sandwiches, it is time to transplant it to other places by grabbing a load of those seedy greens and spreading them where you want them to grow.  For good results, it should be an area of good soil for growing big plants, where leaves will not be lying too thick and heavy for them to sprout the following fall and winter.

          Chickweed is also good for eye medicine, being a mild source of boric acid.  Make a tea with the leaves and stems, let it cool, and drop it in the eyes.  I’ve cleared up many cases of pink eye and kitten eye infections with chickweed tea.  To keep it available year-round in your garden, where it is watered regularly, keep pulling the above-ground portion of the plant before it makes seed.  It will keep growing until it makes enough seed.  It tends to break off at ground level when one is pulling it, so ironically, the way to keep it in your garden all summer is to keep pulling it.  The way to get rid of it all summer is to let it seed out in the spring, or smother it with mulch, the easiest way to lose it entirely.

                             

Rycke Brown, Natural Gardener          541-955-9040        rycke@gardener.com

The Weekly Weeder -- Wild lettuce: Ugliest Weed Ever

          Prickly lettuce is one of the ugliest weeds ever when blooming, and it has started to bloom all over town.  As it bolts, its leaves stick out at unnatural angles, edges vertical, showing off its sharp points.  It grows 3-7 feet tall and spreads out at the top into wide, branching panicle of tiny yellow flowers that soon turn to small, fluffy seeds that fly on the wind to other properties.  It grows all over town, particularly on the neglected edges outside fences, and in cracks in the pavements.  It gets its name from the prickles on the base of its stem which pierce the bare hand that tries to pull it.  It screams seediness and neglect.

Young prickly lettuce

This looks like a domestic-wild hybrid of prickly lettuce

          There are many varieties of wild lettuce.  They all have a few traits in common, starting with being a composite flower (many tiny flowers in a each bloom, often with yellow strap petal flowers around the edges of the bloom, but some have all strap petal flowers and others have no petals) with seeds that fly on the wind, much like their short perennial relative, dandelion.  Unlike dandelion, the flowers grow on branching stems that can vary from a few inches to 18” tall in the case of groundsel in the spring, to 6 feet or more in summer with prickly lettuce and cow thistle, which looks much like a thistle with lettuce flowers but is not as spiny as true thistles.  Some wild lettuce mixes with domestic lettuce, creating interesting red shades.

"Soft" wild lettuce

False dandelion, which has been blooming knee-high in yards with dandelion-size flowers, is a wild lettuce.  This year, we have a new tiny, fine variety, half the regular size with half-inch yellow flowers, which has spread widely in the area and pulls rather easily.  We also have a soft, tall-growing variety with very dandelion-like leaves, with long, vertical branches on the stems that easily bend and buckle because the stems are soft and hollow.  Look up wild lettuce varieties on the internet, and you’ll see several more that grow in our woods, at least one of which is actually pretty, but still spreads like a weed.

          Unlike dandelion, they have tap roots usually only a few inches long that do not grow if cut an inch below the top of the root crown, being mostly annual weeds, though false dandelion is perennial and still dies.  They often pull out of the ground easily, but can be cut out if they break off above the crown. 

          If you weed them out of your yard and they keep appearing, there is an infestation within a half-block.  Wind-blown seeds don’t usually fly very far in a city full of trees.

          Also unlike dandelion, these weeds need no summer water to sprout and grow and tend to invade dry lawns, vacant lots, and cracks in pavements.  But they will sprout throughout the year with water as well.  What they need is bare soil or fine-textured mulch to get a touch of sun and hold the water needed to germinate their seeds. 

Whole-leaf mulch dries out on top quickly.  It deprives lettuce seeds in the soil of that touch of sun and those that fall on top of the leaves of the fine-textured seed bed that holds the moisture needed to sprout and grow.  A few layers of soft leaves will stop spring weeds like groundsel before they are eaten by soil life.  A couple inches of harder leaves will stop most weed seeds, and soften the soil to pull the ones that grow, while encouraging big-seeded perennial grasses to take over.  Bigger-seeded annual grasses will also grow through the leaves and need to be weeded out.  They are a softer, lighter green than the perennial grasses; see “cheat” and “foxtails.”

                               

Rycke Brown, Natural Gardener          541-955-9040        rycke@gardener.com

Leave leaves on your lawn

Just enough leaves on a lawn to stop weeds but not good grass

People are way too afraid of leaves on lawns.  Perennial grass is stronger than you might think.  A pile of leaves will leave a hole in a lawn.  Two inches or more will allow grass to grow through only here and there.  But a few layers will not stop perennial grasses from jumping right up in the spring.  They have enough food in their roots to push through light layers of leaves.  Leaves keep the soil warmer than no leaves and make it more fertile as the worms eat them through the winter, so grasses grow stronger in the spring.

Leaves not only feed soil and keep it warmer to grow grass better, but they stop small seeds like crabgrass; annual rye; Bermuda grass, nut sedge; dandelions; wild lettuce; and groundsel, the first of the wind-blown weeds to bloom in the spring, by keeping sun off the soil.  They also stop mosses, which like these weeds, need sun on bare soil to germinate.  Large annual grass seeds, like cheat and foxtails, can push through a few layers of leaves and need to be pulled.  You can tell them from perennial grass sprouts by their color, which is a lighter green with wider blades than perennial grass, or by their seed stalks later in the spring.  Crab grass, which sprouts in late spring, are very fat even when very short, and are best pulled small.

The weakest perennial grass is probably perennial rye sod, which most lawns on new construction are built with.  It is not a true sod grass; it is a clumping grass held together by plastic net.  Its roots are short for cutting off its clay soil base and transplanting, so it only lasts about 5 years before being invaded by stronger grasses.  Clumping grasses don’t spread by rhizomes, underground stems, but depend on reseeding to refill bare spots that form when clumps die, so it pays to reseed it in the fall before allowing leaves to cover, or rake it into the leaves in spring.  Its seeds are large enough to push through a few layers of leaves when they are ready to grow.  Perennial rye seed grows deeper roots than rye sod, and can create a stronger lawn as the sod grass dies out if it is reseeded yearly. 

Perennial grasses prefer to grow longer north of California, as the sun is lower and they need to be taller to catch the sunlight.  Two inches tall is good in summer, but 3-4 inches is better in winter.  Not cutting grass too short in summer or winter also helps keep sun off soil to prevent weeds and moss. 

A mulching mower can break up the leaves and help them to lie heavy enough between the grasses to keep small weed seeds from sprouting, but whole leaves will not stop the good grass from growing from roots or seed if they are not too thick.

Use leaves to stop weeds

Oak leaves covered with pine needles to keep them in place

Leaves are starting to fall, and they are way too useful to just rake up and put on the curb for pickup.  It’s also a lot of work to rake them out of your shrubbery and flower beds.  Leaves are natural mulch that feed soil and stop weeds, and the thicker they lie, the better they do it.  A foot of mixed leaves can grow great vegetables. They belong on bare soil and mulched beds. 

Leaves laid thick for growing vegetables

Leaves need to be removed from buildings, pavements and paths.   They should not lie too thick on lawns, where they can smother grass, but even there, they can suppress crab grass and other small seeds, while stronger perennial grasses like fine and tall fescues, can grow right through several inches as the soil warms in the spring; they are encouraged by the fertility.  Larger annual grasses, like cheat and fox tails, need a good two inches to stop them.
Most small seeds need a touch of sunlight to allow them to germinate, lest they sprout too deep and are unable to grow out from under their cover.  The larger the seed, the more food it has to grow through soil or leaf cover.  But the smaller the seeds, the more there are to sprout.  Once larger seeds have sprouted, it can be easier to smother them with mulch, if they are covered before they put a lot of food in their roots.

Naturally fallen Red Maple leaves stopping bitter cress and annual rye

Leaves vary in their ability to stop weeds from sprouting.  Very soft light leaves, like box elder, can be eaten by worms, pill bugs, earwigs, and other detritus eaters before fall is even over, and are good for feeding soil, but are fairly useless for stopping weeds in the spring.  Not-so-soft leaves, like red maple, will make it through the winter and stop early spring weeds like groundsel and bitter cress.  Tougher leaves, like oak, sweet gum, and magnolia, stick around all summer, and prevent the germination of later-flying wild lettuce and dandelions and tracked-in crab grass.

Non-broadleaf evergreens also vary in their ability to stop weeds.  Pine needles and needle-type true cedars are tough and take a long time to decompose, but their shape allows seeds to grow through unless they are over an inch thick.  Flatter evergreens, like fir and local cedars, decompose more quickly, but seem to stop weeds fairly well anyways.

One kind of soft leaf can stop weed seeds smaller than a maple nut all summer, even after they are gone: black walnut.  They have juglone, a natural pre-emergent herbicide.  They are not a problem for established perennials, but they stop smaller seeds even after the soil is bare.  Spread under a tree where birds perch, they can stop blackberries and other berry seeds from sprouting where they are laid at least an inch deep.

Use leaves; don’t lose them.  They can save you a lot of work.

October issue, online at GardenGrantsPass.blogspot.com, sold at the Mail Center, 305 NE 6^th St. 

Gardening is easy if you do it naturally.  Litter is tagging, marking the territory of the disorderly.

Rycke Brown, Natural Gardener                 541-955-9040                 rycke@gardener.com