Some people repeat Ralph W. Emerson, saying “A weed is a plant whose virtues remain undiscovered.” But although I appreciate that many weeds do have virtues, I doubt that many gardeners would accept that definition as the final word. Most of us have had extensive experience with Bindweed, Thistle, Goathead, Ragweed, Dandelion and Cheat Grass; not to mention some aggressive natives like Whiplash Daisy, Wood’s Rose and Hairy Goldenaster; and certain herbs like mints, Comfrey and Sweet Grass. So in talking about managing weeds non-toxically, the main point seems to be: How can we keep certain plants under control?
It’s a common idea that Nature, left to its own devices, comes to some kind of balance. If one organism gets too numerous, something else will increase to reduce that population. In the case of monocultures created by humans, there is an enforced imbalance that has to be propped up with lots of energy and effort. So in the pursuit of sustainability, humans are opening our eyes to the possibility of biomimicry, imitating Nature. We are coming to the realization that biodiversity is far healthier and less energy intensive than monocultures born out of the aggressive hubris to control Nature. “Let Nature take her course.” But we can stack the deck in human favor first.
Summer is a successful time to kill weeds, either by mechanical weeding or with herbicides. But toxic herbicides, like Roundup are not solutions we recommend. Roundup in particular was once believed to be quite safe, but now is shown to be harmful to soil life including nitrogen-fixing bacteria, amphibians and is a probable human carcinogen. Roundup formulations can be up to 400 times more toxic than the active ingredient, glyphosate.
At Harlequin’s Gardens, we only sell non-toxic products, but not all non-toxic products are actually effective. Four years ago we tested five non-toxic herbicides and found only two to be really effective: 20% Vinegar and Avenger.
20% Vinegar is 20% acetic acid. It is a non-selective organic acid that quickly kills many weeds, then quickly biodegrades. Repeated use can acidify the soil which is usually a benefit in our alkaline soil. Be careful not to spray desirable plants, and be careful to protect your eyes, especially on windy days. It is most effective on small plants. Repeated applications may be necessary on perennial weeds.
Avenger is a citrus oil weed killer that we found to be equally effective as the vinegar. It is certified organic and is biodegradable. Avenger is non-selective so care must be taken to keep spray off desirable plants. It comes in a ready-to-use (RTU) formula and in a concentrate which may be mixed stronger for tougher, perennial weeds. Like vinegar, it is most effective on small plants, and is best sprayed during hot weather in direct sunlight.
In order to “control” bindweed and other weeds with extensive root systems, don’t let new growth get longer than 2″ or the weed will revive.
BLISTER BEETLE: We have been hearing reports of Blister Beetle attacking clematis. This is a light grey, long beetle that can defoliate a clematis vine in 2 or 3 days. We have found that an organic product called Veggie Pharm actually kills this beetle. It must be sprayed directly on the beetle. (Don’t try to pick up a Blister Beetle; they can raise a blister)
Tree Wrap: We recently saw a big buck with his antlers in the velvet stage. This the time of year deer cause the most damage, when bucks rub their itchy antlers on smooth, usually young tree trunk, tearing the bark. Sometimes a young tree can be girdled in one night. We carry a very good spiral plastic tree wrap that protects trees from deer, rabbits, sun scald in winter. It is superior to paper wraps because it lets air circulate so moisture does not decay the bark. It can be left on in the summer and it expands as the tree grows. Once the bark is older and tougher, it will no longer need protection.
Here is the basic approach which we use at Harlequin’s Gardens to grow hundreds of roses without using any pesticides or fungicides, and only using a few soft controls.
Colorado is said to be the worst state in the US for fireblight, and 2018 was considered by many to be one of the worst years in Colorado. Fireblight is a serious disease affecting apples, crabapples, pears, Mountain Ash and hawthorn, and sometimes quince and pyracantha (supposedly up to 73 species of plants).
It has been suggested that this period of the 21st Century might well be called The Age of Biology, because the biggest challenges will be biological and the biggest breakthroughs will be in the realm of biology.
In this article, we will continue the discussion from the last issue on Biological Agriculture and Gardening, but this time going into specifics of biological thinking, biological discoveries and applications that improve plant and food success with biological solutions.
Food safety is one of the most critical issues of our time. What we eat is directly related to our health, and health care has a direct impact on our personal and national economies. Major chemical companies like Monsanto, Bayer, Dow and Dupont have introduced 86,000 synthetic chemicals into our environment, food, drugs, cosmetics etc and most of them have never been tested for toxic effects on human health and the environment. Since the mid 1990s, some of these same companies have been filling our grocery stores and feed stores with genetically engineered food products which may be causing serious health problems but are being approved by our government without safety testing.
How can we deal with all the bugs and diseases without using toxic poisons, and how can our gardens really produce without high-powered chemical fertilizers? Many people wanting to garden sustainably are asking these questions. And it is not easy to find the answers, partly because the answers are not simple. I want to admit this up front, but don’t be scared off, because it’s not that hard to garden sustainably once you get the hang of it. However you must know that you can’t just exchange a slam-bam chemical approach for a slam-bam sustainable approach.
Last month we raised the issue of invasive introduced plants and the idea of being responsible gardeners who respect our native habitat and make an effort to not release invasive plants into the wild. We began with obvious noxious weeds that are having strong negative impacts on our native populations of plants and animals. This month again I am profiling weeds which have been declared as noxious, but this time a question is beginning to arise about under what circumstances are some of the less aggressive weeds invasive? In other words, is it possible that we might find a middle way that guides us strictly with the truly harmful invasives and more leniently with the less aggressive and more useful weedy plants? These are questions I am asking myself and will be asking in future interviews. We also welcome your views on this issue.
In February 2000 President Clinton established the National Invasive Species Council. Agriculture secretary Dan Glickman, Commerce Secretary William Daley and Interior Secretary Bruce Babbitt were asked to work together on a plan to minimize the economic, ecological and human health impact of invasive plants and animals not native to the US. The executive order on Invasive Species directs federal agencies to prevent the introduction of invasive species, to control populations of such species in a cost-effective and environmentally sound manner, to monitor populations, restore native species, conduct research and promote public education on invasive species.
One of the hot subjects in horticulture these days is the issue of the invasiveness of introduced plants. Since they did not evolve here, they lack natural enemies, and whereas most are harmless, some have engulfed vast areas of wilderness, national forests, range and farm lands. This has led some people to campaign for “natives only” and others to attack the introduction of new plants as an ecological nightmare. In response to these attacks some in the plant industry have dismissed these fears as invalid over-reactions. As Colorado gardeners, most of us can be both excited by new plant introductions that are well-adapted to Colorado conditions, and feel very protective of our natural ecosystem and our native plants. In a series of articles, we hope to uncover some truths regarding these issues and to educate ourselves about how to work with this situation in a constructive manner.
It used to be that beauty was enough. If the lawn looked good and we had a few shrubs and a few flowers, we could relax, having done our duty to the neighborhood.
Now we have to be water-wise, save the bees and the Monarch Butterflies, and on top of that, we’ve got to have Biodiversity.
I think this is a good trend. Gardens are more than something to look at. They are a piece of Nature and the more diverse they are, the more like Nature they are.
This is a bad year for fireblight which is a bacterial disease which affects mostly apple, pear, crabapple, hawthorn and Mt. Ash. It is spread in the presence of moisture and enters the trees through wounds and open blossoms. Colorado is the worst state in the US for fireblight.
Because of our moist spring and extra wounding caused by hail, there is a lot of infection. Symptoms include black, hooked twig ends, brown or blackened leaves, dried up fruits and sunken cankers that can be a dull orange or black. Fireblight is a difficult disease to manage because there is no cure. Spraying chemicals is not recommended by CSU because they are not very effective, timing is critical and spraying must be repeated.
What is it? How bad is it? What do we do about it?
Emerald Ash Borer is an invasive beetle that found its way from China or eastern Asia to the US, stowing away in shipping crates. It was first identified in 2002 and has since spread to 22 states. In September 2013, Emerald Ash Borer (EAB) was discovered in the city of Boulder, which is the first known presence in Colorado. Since then a team has been stripping the bark from samplings of ash trees in Boulder to determine the extent of its spread. It is suspected that EAB has been in Boulder for three to four years.
We gardeners are always looking for tough plants. And those of us who are pursuing the elusive “sustainable garden” are searching for Colorado-adapted plants that do well with little or no care. But that is not enough. A sustainable garden is one where there is a balanced ecosystem of plants that can change as conditions change, to favor first one species and then another, but no plant should take over the entire space. Those dominating plants are the ones I call real weeds: the garden bullies.
One of the most damaging and most perplexing diseases of the Front Range is fireblight. It is a bacterial disease affecting apples, crabapples, pears, Mt. Ashes, pyracanthas, quinces, hawthorns and occasionally cotoneasters. Fireblight does not affect cherries, plums, peaches or shade trees.
When the bacterium with the lovely name Erwinia amylovora enters the trees through an opening such as a wound, a pruning cut, the open blossom or leaf pores, the tissues quickly die causing blossoms and leaves and young twigs to suddenly wilt and turn black as if scorched by fire (hence the name “fireblight”). As the bacteria spread through the tissues, secondary infection continues through the season and bark areas die, become sunken and turn black or reddish-orange. These areas are called “cankers”. Sometimes large numbers of leaves turn black but the infection stays confined to small twigs; sometimes entire large branches die; occasionally the entire tree will die.
Japanese Beetle is one of the most damaging insect pests in the Eastern and Midwestern US, but until recently, Coloradans were spared that challenge. It entered the US in 1916, but took until 2003 before a population was established in Colorado. This first infestation was in the Palisade area on the Western Slope. Even though eradication efforts were mostly successful there, established populations have been found since 2005 in Pueblo, southern Denver, Englewood, at DU and at Denver Botanic Gardens. Smaller populations are being seen now in Boulder and Jefferson County.
Nolo Bait is not a poison. It is a parasite that only affects grasshoppers and Mormon Crickets. It will not harm people, pets, wildlife or beneficial insects. It is most effective on small grasshoppers. In 3-4 weeks up to 50% of the grasshopper population will die. In addition, their eggs will be infected for the following season, and because grasshoppers are cannibalistic, they spread the disease. Put out shallow trays of the bran bait in small quantities. Wind, rain and contact with soil organisms can reduce bait available to grasshoppers.
Ducks, chickens, turkeys and guinea fowl can significantly reduce grasshopper populations. They must be fenced and put inside a safe structure every night to protect them from predators. They will also eat some plants, like vegetables.
Corn Gluten: made from corn it functions as an organic weed-and-feed. It works by keeping all seeds from germinating. Once a plant (or weed) begins to grow the Corn Gluten will not harm it. Very effective when used twice a year, in October and February. The effect lasts 6 months. The feed part is the 9% nitrogen fertilizing effect which thickens grass and stimulates the growth of all plants.
20% Vinegar: this natural acid will burn plant tissues it is sprayed on. Best to apply in bright sunlight and hot days. Spray thoroughly. Very effective on annuals; perennials may need more than one application. Be careful not to overspray on desirable plants as it is non-selective. Repeated use can acidify soils which in our alkaline soils is not usually a problem except for alkaline-loving plants like lilac.
Overview: The Good News: 100,000 insect species; only 200 pests. We do not need neonics or any toxic pesticide to grow plants well. The solution is human attention, biodiversity, nutrient-dense soils, application of nontoxic management, and tolerance.
The Bad News: Most people and most nurseries don’t know the good news. They believe the chemical companies that we need to fear and attack insects and fungi as enemies.
More Good News: The concern of ordinary citizens who call nurseries and businesses and ask them if they are using systemic neonic poisons in their plants, is having a powerful effect. These companies now know we care and will buy plants that are neonic-free if we can. This could get them to change.
Pyrethrum is one of the best known botanical insecticides, effective against a wide variety of insect pests and generally considered safe to use. Is it really safe? To answer any question about pyrethrum it must first be explained that what is referred to as “pyrethrum” can be many different products. There is pyrethrum, the raw flowers; pyrethrins,the extracts from the flowers; and pyrethroids, synthetic pyrethrum. In addition many other insecticides and enhancers are often added to formulations which are called “pyrethrum”.
Pesticides were never a good idea. They were designed to make money from petroleum, not to benefit the public good. Pesticides, fungicides and herbicides are poisons that were developed to kill life. Not only has this approach poisoned our earth and ourselves, it has failed to control Nature. Our soils are less productive, and weeds and pests have adapted by becoming resistant. Stronger poisons are not the answer.
In the last 20 years, the new “nicotine” pesticides (neonicotinoids) have become the industry standards because they are less toxic to people and animals than the old organophophate pesticides, and that is good. But the neonicotinoids (neonics) are even more toxic to insects; they last 3 months to 5 years; all parts of the plants are poison, and the poison goes into our water.
I enjoyed the article by Renee Galeano-Popp in the fall 2016 Aquilegia, but I would like to take exception to her statement that in terms of alternate hosts of gooseberries and currants that “just about any Ribes species will do.”
Currants and gooseberries have been increasing in popularity among gardeners because their fruits are high in immune-building phytochemicals, because they take up less space than a fruit tree, are easier to pick the fruit, are productive even with late freezes and recent introductions are better flavored and less resistant to diseases.