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: Aphids on Roses are Good

          A couple of weeks ago, I saw a bad infestation of aphids on Betty Boop, my favorite rose.  I also saw some soldier beetles already on the job, eating them.  I checked them a few days later, and both aphids and soldier beetles were gone.

But I know that those soldier beetles laid eggs under the leaf mulch in my beds, and their larvae will be patrolling under that mulch for the next 10-11 months, eating any insects they can catch and kill.  They pupate and become adults in April and May and emerge, ravenous for aphids to make their eggs.

I learned this the spring after I bought my house, in 2000.  All the roses that came with the property were heavily infested with aphids, and I waited for weeks for lady beetles to show up and clean them up and make their young, who likewise eat aphids.  But the infestation just got worse, until I got nervous and decided to spray them with soap.  I was heading out there with the spray bottle in hand, when I saw about 50 soldier beetles flying around the most infested bush and mating—so I didn’t spray but I did look up these red and black beetles and learned their habits.  Within a few days, both aphids and soldier beetles were gone.

I had been waiting for lady beetles because, in Arizona, I had a single broccoli plant that was infested with aphids.  I had learned that aphids are specific for particular types of plants.  This being the only brassica in my garden, I knew there was nothing else that they would eat, so I didn’t pull the plant, wanting its seeds.  After a while, it became a lady beetle factory, feeding at least 100 of a several different sizes and colors of lady beetles, including young and pupae.

But here in Southern Oregon, lady beetles have to compete with soldier beetles, which, with their short adult life span, are more ravenous when they emerge from the mulch.
Later in the summer, I tend to have aphids on corn, which attract lady beetles in large numbers and don’t really hurt the corn.  They also do the same thing on sun flowers, though birds are more likely to eat them there.  A couple of years, I had large, grey aphids on my fringe pussy willows, which were eaten by hummingbirds, chickadees and woodpeckers.

Aphids are manna for predators that eat them, crowding together in large numbers for easy picking, full of sugar as well as protein.  Those that grow on poisonous plants, like hellebores, often are not eaten by anything.   I have seen soldier beetles eating aphids on hellebores, but only once, so I am more likely to spray them there.  But most of the time, they are useful to bring in predators that might stick around and eat other insects as well. 

But soldier beetles won’t lay eggs where there isn’t any mulch cover for their young.  Don’t use finely-ground bark, which leaches its natural preservatives into soil and kills everything in the soil but plants.  Coarse bark, like walk-on fir or nugget bark, can provide shelter and help keep soil moist, but the best garden mulch is leaves, which feed fungi and soil life and become rich soil.

         

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

Don’t till; mulch and plant in it

 Late spring, tomato planted in leaves with rocks for warmth; pepper foreground, planted in leaves, compost and 4 x 8 top mulch with rocks for more warmth and predator shelter; 4 x 8 path between 

This is the season when people start thinking about tilling their vegetable garden areas, but it is too wet to work the soil.  It’s a good time to start building mulch beds that you can immediately plant seeds and starts in.  You can do this anywhere you grow other plants as well; vegetables don’t need to grow in their own mini-farm in your yard; they just need good sun.  They can be worked into your landscape.

          Another good reason to mulch rather than tilling in compost is that tilling brings weed seeds to the surface where they can grow; kills many earthworms and soil predators; and mixes air into the soil that decomposes organic matter faster, causing nutrient loss from leaching and evaporation.  Letting worms work in nutritious mulch captures its nutrients in worm castings that release nutrients slowly and have lighter, better texture than uneaten soil, while coarse top mulch provides a home for predators like ground beetles, centipedes, and soldier beetles while protecting soil.

Fall: a compost pile of layered leaves and garden plants, about 2 feet high, built for growing watermelons, a small yellow Red Hot Poker on one side, a large growing area behind, about 8" deep in leaves.

 February: the pile has settled about 6 inches.

February: compost is added to speed decomposition.  The compost will be covered with 4 x 8 sand before planting the watermelons, with large rocks in the center to plant the seeds around.  Naked leaves will keep weed seeds from landing and sprouting around the watermelons.

        You can build beds with leaves, mainly available in the fall, a foot of which will grow huge vegetables.  For winter vegetables and small seeds, you can put an inch of compost on top, covered with an inch of coarse mulch like pine needles or shredded or nugget.  Scatter small seeds on the surface and plant starts and large seeds into the leaves.  Compost keeps the leaves wet and provides nutrients to help them rot faster; coarse mulch keeps it from drying out.  You can plant summer starts and large seeds into leaves alone for best weed control, as dry surface leaves make a poor seed bed for weeds.  This is just one reason why leaves make the best mulch for maintenance.

A potato popping up in February

          Leaves being not so available in spring, you can build beds with straight compost.  Six inches is equivalent to a foot of leaves and is ready to grow plants right away.  Two inches is good for ornamental shrubs and flowers.  This compost also needs to be protected from sun by coarse mulch, which is also needed for shelter by predators that keep pests under control.

          Paths also have to be mulched, to keep weeds from growing.  Like the beds, weeds have to be pulled when they grow anyways.  2 inches of coarse mulch like wood chips, chipped trimmings, or coarse bark can keep weeds down for a year and has to be renewed yearly.  An inch of 4 x 8 sand, river sand sifted to 1/4-1/8 inch, can be weeded with a hula hoe (AKA stirrup  hoe or scuffle hoe) when the weeds are small, and the weeds raked up, saving bending for each weed.  It is cleaner than organic mulch paths, easily blowing clean, while raking sifts dirt to below the sand.  It's also good for mulching over compost, heating the soil for fast growth.

          Beds made of leaves or mulch will spread into the paths from feet and birds and squirrels seeking food unless they are edged with something solid.  Cobble rock about 6 inches high, can be laid in curving lines for beauty and smooth lines of travel, end to end.  Brick can be used, but is more exacting to lay.  Wood lends itself only to straight lines and eventually falls apart.

February 2015 issue, online at GardenGrantsPass.blogspot.com and at the Mail Center, 305 NE 6^th

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

Good mulch brings good bugs

Leaves under butternut squash and tomatoes

A gentleman of my acquaintance asked me what to do about squash bugs.  I said that I never really have a problem with squash bugs.  Turns out that the people he is helping with their farm are using plastic mulch to control weeds and row covers to try to control insect pests. 

I pointed out that what controls bad bugs are good bugs, predators that eat the plant eaters, and the most effective ones require good mulch like leaves to live under.  When you have plastic mulch or bare soil, you lose all the spiders, centipedes, ground beetles, and soldier beetles, to name a few of the most effective predators in the garden.

Warming rocks under peppers.  They warm the soil at night, cool it during the day.

Almost all of these predators live exclusively under loose mulch and rocks.  Soldier beetles spend the spring month of their adult lives flying, eating aphids, mating, and laying their eggs under mulch, where their larvae live under the mulch the remaining 11 months of the year, eating anything they can catch and kill.  If you have no loose organic mulch, you will have no soldier beetles laying eggs, and few or none of the others.

He said that the plastic mulch is needed to keep weeds down.  I said that leaves do that.  Not only do they keep sun off the seeds that need light to sprout, but they are a poor sprouting surface, as they dry out quickly, so seeds that land on top cannot sprout either.  Only larger seeds can get through 2 inches of leaves, and they are easily pulled; it is the tiny seeds that need sunlight on soil that are hardest to control without mulch.

4x8 sand and rocks under peppers and melons.  Insects are not under sand, only under rocks.  Sand is too hot.  Walk-on fir bark is beyond.

Plastic mulch cannot feed soil, while leaves are the natural food of worms and other detritus eaters, who turn them into soil.  One eater of detritus is the earwig, which many think of as a pest.  They are rather creepy in their habit of hiding in flowers and foliage during the day and coming out when they are brought into the house, but they don’t generally eat live plants; they eat the fungus out of dead or living leaves and can actually eat fungus, like rust on hollyhocks, out of your plants. 

Wikipedia considers earwigs omnivorous and says that they eat insects and plants.  Scientists seem to have missed that they love the fungus-infected parts of leaves.  They are said to eat corn silks as well, but I always have many earwigs and no corn silk damage.  Without fungus-ridden rotting leaves to eat, earwigs have only the softer parts of live plants to eat.

Two inches of leaves is great for stopping weeds and feeding soil.  12 inches or more can make wonderful soil and grow huge plants as they decompose.  Start next year’s garden by gathering your leaves this fall, rather than giving them to the trash company for compost.  They will make wonderful compost in your garden if you just let them lie there, and add to them.

Control Cobweb Spiders with Mist

The "cellar spider," family Pholcidae, is our most common local cobweb builder and the one referred to in this article.  They grow up to an inch or so across.  Black widows and their relatives are more commonly considered cobweb spiders, going by the Internet.  

Cobweb spiders have hatched, and are dirtying houses with their dirty little webs.  Unlike other web builders, a cobweb spider doesn’t clean and repair its web; it camps until the web gets dirty and then moves on to another spot, the homeless vagrant of the web-spider world.  A dirty, visible web is useless to the spider, except to steer flies into its new, invisible web.  But they sure mess up a house, inside and out, and shrubbery as well.  Cobwebs scream neglect to thieves and encourage other disorderly conduct, like littering and breaking windows.

Last summer’s fires were very hard on cobweb spiders and other web builders, showing up their webs with ash.  Cobwebbers starved except under cover; they could not build new webs fast enough, though they sure tried, covering shrubs all over town.   There have been relatively few cobwebs this spring until now.  

Daddy Long Legs, AKA harvestmen, family Opiliones, are not spiders, having one body section, not two.

Daddy long-legs have become common where they were rare, as they don’t build webs, but just walk around.  Cobwebs certainly mess up their hunting range, and could be a hazard to them.

Rain is also hard on cobweb spiders, because they are delicate, and too much water can stick their legs together.  Rain also shows their webs, so they build webs under cover until the weather is dry, when they spread into the shrubbery.  This is another good reason to use sprinklers rather than drip or soaker hoses, besides making rain.

A customer’s neighbor in her duplex has rough siding covered with tiny, dirty spider webs, with larger webs under the eve on his front porch, but she had few on her portion of the duplex, and she has needed little web cleaning thus far this year. 

This standing mister usually sells around $10.

Last year, during the fires, she started using misters to keep her plants happy, settle the smoke and breathe easier, and she has loved the results.   When they are on, it takes only a few minutes for them to show all the webs within 8 feet, allowing this gardener to clean them off with a web duster. 

There are many brands of this tool available on the web.

A web duster, a pom-pom shaped broom head that can be attached to an extendable pole, is also needed for cobweb spider control, since as soon as the misters are turned off and the webs dry out, they are good for catching food again, and the mist doesn’t reach to the high eves.  Using a duster alone, it is an endless battle to keep the cobwebs down.  The two together can do wonders.

If you don’t have misters, cobwebs in shrubs are better controlled with hoses and spray nozzles that adjust from spray to jet than with a web duster.  Or you can use a sprinkler and web duster.  But the jet reaches inside the shrubs where you can’t see.

How to Control Insect Pests Naturally

The EPA just approved another systemic pesticide, saying that it is needed because the pests have become immune to previous poisons.  This is a losing game, as plant-eating pests can easily outbreed the poisons, while their predators and bees cannot.  Systemic pesticides, which are distributed into every part of the plant through its roots and stems, are particularly dangerous to bees, hummingbirds, and predatory insects, which rely on nectar for fuel.

The smallest pests are inherently the hardest to control in a conventional yard or farm, yet they can be easily managed in a naturally managed landscape that makes their predators comfortable and lets them breed. 

Such pests are not pestilential all the time; it is only when they infest and become a plague that they become a real problem.  If most plants that sprout in natural conditions were able to grow to maturity, they would be too small and crowded for the good of the rest of us.  Herbivorous “pests” thin most of the plants as they grow, the smallest and weakest ones first.

An infestation of any pest is a feast for any predator that eats it.  Given a chance to do their job, predators multiply as they feast, and the population of the pest crashes back to pre-infestation levels.  In a natural landscape, any infestation is a temporary affair.  When ladybugs and soldier beetles home in on aphids on roses, they don’t last long.

 

 Nearly mature ladybug larvae on my mature corn, with grey aphids, one week after ladybugs mated there.

A few days after the previous photo, the corn is cleaned of all but aphid trash.

Three things make insect predators comfortable: shelter; food; and water.  The shelter for many predators is leaf mulch; coarse bark works as well.  Adults and/or larvae crawl around under the mulch, eating whatever they can kill.  At night, many crawl out of hiding and stalk their prey on the plants.  Ground predators include soldier beetle larvae, ground beetles, ants, spiders, centipedes, and even earwigs, which eat fungus-infected leaves, not healthy plant tissue.

 Soldier beetle, credit www.marinrose.com.  Ground beetle, credit www.naturephoto-cz.com.

Since insects have little sugar or fat, their predators need an energy source like nectar, and many of them, like tiny parasitic wasps, prefer small flowers, the smaller the better.  (Aphids though, are full of sugar from sap, and piss out the excess, attracting wasps). Carrot flowers qualify, as do chickweed and purslane, chickweed in spring, purslane in summer.  Both of these low, spreading annuals are useful and edible, and don’t bother other plants much.  Deadhead your carrot flowers; they are likely to make half-wild seed that makes white, skinny roots.

Water is needed as well.  If you buy ladybugs or spider mite predators, it is important to water the tops of the plants so they can take a first drink.  Bees, wasps and birds mob sources of water in hot, dry weather.  Spider mites love dryness and shun humidity.  Sprinkler irrigation and misters are best for providing the water that your predators need, along with baths and fountains for birds.

Cobweb Spiders Camp

A tool every resident should have is a web duster, a broom on a pole with a puff head, to take out cobwebs inside and outside the house.  The “Webster” head can be found at Diamond, with a variety of poles, extendable and otherwise.  Mine has three sections and extends to 16 feet to get the eaves on the second story.

The cobweb spider is the homeless vagrant of the spider world.  Rather than build and repair a strong, long-term dwelling in a good location as does the classic orb weaver, it builds and camps in a small, quick, weak web anywhere it can find a surface to sling it, preferably out of the rain, but anywhere in dry weather, like now. 

As soon as its web gets dirty, visible, and therefore useless, it moves on and builds another nearby.  The dirty webs actually steer its prey into the invisible new web.  And they can make even a pretty shrub or house look neglected in short order.

I saw this effect on one of my most beautiful properties, when a mister showed up the cobwebs that had appeared on the ground cover overnight.  Approaching the door, I saw a piece of litter, a gas receipt, crumpled and thrown on the ground cover by someone who had actually been at her door.  Unconsciously, the person saw the cobwebs and threw his trash into the ugliness of the webs, despite the beauty of the rest of the property.  A few webs are all it takes to turn on the unconscious urge to litter.

Cobwebs are all over town, particularly infesting hedges and certain shrubs that they favor, like juniper and rosemary, but also every neglected inward corner of a building, particularly under the eaves.  


I’ve been petitioning door-to-door lately, and the cobwebs around the front doors make one shudder.  Your gardener or landscape maintenance man cannot visit often enough to clean these up; it is up to residents.  

The way to actually discourage these spiders is to sweep their webs before you see them, while they are still useful to the spider.  If you only sweep the visible webs, you aren’t even bothering the spiders.    

Sweep every corner where they might build, particularly where you see a spider but no web.  When you sweep them off a building, it pays to stick around for a minute or two while they start climbing right back up where they were, and sweep them down again.  This will often make them go somewhere else.

Another way to clean up cobwebs is with a hard jet of water; this is probably more effective than a web duster in shrubs, which are invaded only in dry weather, and where it is impossible to sweep all the webs.

Earwigs? No problem!

Earwigs are a creepy nuisance at times, like when they crawl out of freshly picked flowers or lettuce heads, but they are not a pest. They actually clean up fungal infections on plants.

A typical earwig.  Credit: animal.discovery.com

                   For several years in this town, I found that one could not grow a hollyhock to bloom without it becoming covered with an ugly rust by the time it bloomed.  I would cut them down when they got ugly and let them re-grow to bloom later in the summer, when the rust is not so prevalent.

          But one year, I didn’t see any rust on my hollyhocks, and so didn’t cut them down.  As they were blooming, I was lying on the lawn one day, looking up at them, and noticed that the leaves were full of tiny holes in the same pattern as the rust would make, and so was a butterfly bush.  That evening, I noticed earwigs climbing the butterfly bush as it got dark, and put two and two together; the earwigs were eating the rust before it made spores and became colorful.

          I had previously noticed that I had a great many earwigs in my gardens and thought about various strategies for getting rid of them, though I noticed no damage that I could attribute to them.  Now I realized that they were actually useful, and stopped worrying about them.

          In Landscape Management at RCC, our teacher pointed out that plant diseases like rust make typical damage patterns that differ from those caused by plant-eating pests.  After several years of observing such damage, I was able to see the difference right away between pest damage and fungal damage cleaned up by earwigs.  Since then, I have noticed earwig work on other plants with other fungi.

          Earwigs are just one of the many beneficial insects that are encouraged by leaf mulch.  Many predators of plant pests live under mulch and rocks, along with pests that they may or may not eat, like snails, slugs, grubs, and grasshoppers.

 

 A variety of soldier beetle common in Southern Oregon.  Their color patterns vary widely.  

Credit: www.marinrose.org

Soldier beetles eat aphids in April and May and then lay their eggs in mulch-covered soil.  Their velvety black larvae crawl under the mulch for the rest of the year, eating a great many insect eggs and baby bugs.  You will rarely if ever see the larvae; they are exceedingly shy. It’s hard to even find photos of them. 

 A ground beetle typical to Southern Oregon.  Some are iridescent; some have big heads.  

Credit: www.naturephoto-cz.com

Ground beetles, spiders and centipedes also hunt beneath the mulch.  Leaves aren’t the only mulch they like, but they are probably the best, apart from a tendency to be eaten up by worms, pill bugs, millipedes and earwigs.  Coarse bark mulch can keep the soil covered when the soft leaves are eaten up.  Keep your soil predators happy with good mulch, and you will have few pest problems. 

         

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