Uncategorized – Page 45 – The Garden Professors™

Pesticides and Wildlife

If you follow this blog then you know that I write a lot about pesticides. They’re something that I enjoy reading about and studying. For whatever reason, I find them fascinating. That said, they can be some of the worst things for wildlife. But there are pesticides that are more “wildlife compatible” than others, so today I’m going to cover some of the worst pesticides that you can use in terms of wildlife, and some of the pesticides that might be more acceptable (though far from perfect).

First, here’s a brief rundown of pesticides that have been some of the worst wildlife offenders over the years. Fortunately most of these are gone.

1. DDT – long gone (though I know people who still have old bottles locked up in chemical cabinets here and there). Modern evidence points to it not being as bad for human health (cancer) as many made it out to be, but it was a mess in terms of environmental effects — it built up in the environment (it is stored in the body and is not rapidly excreted — in large part because it isn’t water soluble — so when a predatory bird ate a small mammal who had DDT on (or in) it, all of that DDT would stay in the bird — and the DDT from the next mammal it ate, and so on — this is called biomagnification) and resulted in predatory birds producing thin-shelled, barely viable eggs. Another problem with DDT was that it lingered for a long time — it doesn’t break down quickly. It had other problems too – but the biomagnification and persistence issues were the most obvious and, at least to me, the scariest.

2. Endrin – Relatively closely related to DDT, but a lot more toxic to a lot more animals and so a lot scarier. Once upon a time this stuff was used to all but sterilize fields. Toxic to everything that moves, and, like DDT, it built up in the environment. This stuff was (fortunately) never really used by homeowners.

3. Temik (aldicarb) – Nasty, nasty, nasty. EXTREMELY high acute toxicity, AND it’s water soluble. A pesticide which I have had to use in the past. Apply it to a tree (I was working with pecans when I used it) and that tree’s foliage would be free of any insects. And, amazingly, the stuff didn’t translocate to fruits and veggies – if it weren’t so darn toxic to things besides insects it would have been a great insecticide – some people still consider it a great insecticide. This stuff was known for its misuse. Apply it near a weed which deer eat and that weed would absorb the pesticide and poof! No more deer. Agonizing death too. Wolves and coyotes could be poisoned with just a little bit of tainted deer meat. This stuff wasn’t supposed to be used by homeowners, but, again, it is known as much for its misuse as its use.

Fortunately most of those over-the-top killers are gone or on their way out. Still, in your garden you do have the opportunity to use some poisons which it would be best for you to avoid if you’re interested in saving/protecting wildlife. These poisons are called “broad-spectrum” poisons and they are preferred by many because they kill so many different types of pests. Unfortunately being able to kill many kinds of pests usually also means that they’re able to kill many types of good creatures. Many pesticticides such as sevin (carbaryl), pyrethrin, orthene (acephate), and sulfur are broad spectrum poisons that you should avoid, but here are some that, if you want to conserve wildlife, you should be especially wary of.

1. Permethrin – This is probably the most used broad spectrum insecticide used around gardens today. It will kill just about any insect which it touches and it lasts for about 10 days. It is certainly effective, but it shouldn’t be used by anyone who wants to encourage insects or the birds who eat insects in their gardens.

2. Metaldehyde – This is a very effective slug poison. It is both attractive and deadly to dogs and cats, and is thought to affect birds and small mammals as well though there aren’t as many documented cases of wildlife poisoning as there are of domesticated pets being poisoned.

3. Copper sulfate (Bordeaux mix) – This is an organic fungicide that is often overapplied because it is considered safe. It can limit the plants which grow in an area, and it is extremely toxic to aquatics – keep it away from water. Finally – copper doesn’t break down – as you use it over the years it will build up in your soil – so try to stay away from it.

And finally, here are some which, if they are used properly, are less likely to affect wildlife.

1. Kaolin clay – it’s not popular, but it’s out there if you look for it. This is a type of clay which it sprayed onto plants to protect them from insects. It tends to work pretty well (it’s not perfect), but it has minimal effect on wildlife.

2. Insecticidal soap – It will kill some insects that you don’t want to kill, but it’s a heck of a lot better than permethrin. It is unlikely to hurt mammals or birds.

3. Roundup – The controversial part of me wrote this. Roundup has been implicated as doing all kinds of things to aquatic organisms, but, if it is only sprayed on the leaves of the plant you want to kill, it is not going to cause any significant environmental damage (besides removing a plant that wildlife may want for food).

Want more bird visitors? Nonnative plants may be the answer

We’ve posted before about the native vs. nonnative conundrum, especially as it relates to invasive species. So let’s complicate the issue a bit more by considering how birds are affected by our landscape choices.

About 10 years ago my UW colleague Sarah Reichard and I collaborated on a literature review on the interaction between birds and non-native plants. While we know that invasive plants can displace native plants and create less biodiverse environments, the resulting impact on species like birds is not so cut and dried. And what about noninvasive, nonnative plant species? How do they affect bird populations? Here are some of the practical bits of information that we found:

1) Nonnative shrubs and trees are often chosen for their brightly colored fruits, especially those that produce them in a different season than native plants. Winter color is highly valued by gardeners.

2) Frugivorous birds (those that eat fruit) generally benefit from the introduction of fruiting species as an additional food source, even if the species is invasive.

3) Birds tend to prefer fruits that are red and/or black, or that have red arils or pseudoarils.

4) Birds tend to prefer fruits that offer the most pulp; interestingly, highly invasive plants species tend to have larger fruit displays and therefore higher bird usage than less invasive relatives.

5) Additional food sources can allow frugivorous and omnivorous birds to expand their ranges and/or their breeding seasons.

6) Nonnative shrubs and trees with structural features such as thorns and spikes can provide protection to small birds from predators.

It’s clear that birds are highly adaptive and will quickly learn to utilize new food resources – and in doing so, may contribute to their spread through seed dispersal. It’s enough to make your head spin.

Here’s what I recommend for choosing bird-friendly trees, shrubs and vines:

1) Use native species first if they are adaptable to your site conditions. (Note: many native species, especially those of forested environments, don’t like urban conditions.)

2) Be sure to provide structural diversity in your landscapes – groundcovers, small dense shrubs, larger open shrubs and small trees, big trees, and vines – to provide shelter and nesting habitat.

3) Before choosing nonnative species, check the web for information on invasiveness. The USDA Plants Database (http://plants.usda.gov/) has information on invasive species. If it’s invasive, please don’t plant it!

4) Birds see best in the red end of the color spectrum, so select plants with fruits and flowers that will attract them.

The Garden Professors Go Wild!

It’s ‘Wildlife week’ on the Garden Professors. One of the most common questions that we get when speaking to garden groups is, “What can I do around my home to promote wildlife?” My stock answer used to be, “Throw a party!”, but only a handful of people ever got it so I’ve backed off of that one. Anyway, since the subject of gardening and wildlife comes up so often we’ve decided to dedicate a week to the topic.

Questions about wildlife (the animal kind) always take me back to my undergraduate forestry days at Washington State University and Dr. Zamora’s Wildlife Management course. Even though I’ve always been more of a plant person than and an animal person, I found this to be a fascinating course. In fact, assembling the winter browse twig ID collection was one of my proudest undergraduate achievements. Doesn’t seem like much; but try wandering the Palouse hills in the dead of winter and see if you can indentify 50 browse species without the benefit of leaves, you’d be proud too! In addtion to a notebook full of mounted twigs and a mild case of frostbite, I took away from the course several key principles of wildlife management that have stayed with me over the years.

What do wildlife need? In general, all wildlife need four basic elements: food, cover, water, and space. The specific types and amounts of these elements, of course, will depend on the type of wildlife you wish at attract. Homeowners can provide or enhance these elements through plants or through other, non-living means. Important non-living components include feeders, bird-baths or other water features, piles of rocks or sticks (provide cover for small animals), salt, and standing or fallen dead trees (provide habitat for cavity-nesting birds and mammals). Plants can provide both food and cover. Important plant components in designing for wildlife include evergreen conifers for cover, summer fruits and berries, fall fruits and seeds, winter fruits and seeds, flowers that provide nectar, and trees that provide nuts and acorns.

At this point the questions often turn to the importance natives versus exotics. In light of Doug Tallamy’s book, Bringing Nature Home, many people assume that only native plants can serve these functions. But there are several factors to consider here. First, Tallamy’s discussion is largely focused on co-evolutionary relationships between native plants and native insects, and even here some of the reasoning is stretched thin (see Linda’s Feb. 12 post). There is more to supporting wildlife on a broad scale than insect/herbivore interactions. Non-invasive exotic conifers, for example, can certainly contribute winter cover, vertical structure, and edge effects. And, while some animals have evolved very specific diets (think koalas and eucalyptus), many herbivores are generalists and in some cases even prefer to feed on exotics. So, in thinking about wildlife it’s important to consider function and providing the elements animals need than to simply fixate on whether plants are native or exotic. This is especially true on tough, disturbed sites where natives may be poorly adapted and unable to survive. Habitat provided by an exotic will be preferable to no habitat at all.

Lastly, another factor to consider is whether attracting wildlife around your home is always a good idea. Along with the wildlife we’d like to see, improving habitat may increase the likelihood of running into critters (skunks, raccoons, possums) that we’d rather not encounter on the way to take the trash out late at night. Also, in many parts of the country, people and their pets are encountering large predators such as cougars and bears with increasing frequency. Obviously a lot of this is due to human encroachment into the predators’ habitat, but it may be prudent to consider a ‘defensible space’ strategy as we do for wildfires. Keep the elements that are likely to attract larger animals a safe distance from the house. Stay tuned for more as ‘Wildlife week continues’.

NOTE: Thanks to my high school choir-mate and college soccer team-mate, Tim Schlender for the timely wildlife habitat cartoon.

Big Trees for Crime Reduction

Like Linda, I believe that we don’t plant enough bare-root trees. Trees that are harvested and sold bare root tend to establish better and recover faster from transplant shock than trees sold in containers or as B&B (balled and burlapped) stock. But, in general, trees that are purchased in as bare-root stock are smaller than the other two styles, with B&B generally being the production method which yields the largest trees.

I disagree with Linda that, as a general rule, B&B stock should have its roots washed off prior to transplanting — I’ve done it and I’ve lost trees. Most of the B&B trees that I know of where root washing has been successful have been small, relatively easily transplanted stock. Once we have a few nice, big, long term studies that shows that B&B trees with their roots washed perform comparably to, or better than, normal B&B trees I’ll start to believe. (I will note that, as a rule, it looks like B&B stock is dug and cared for much better here in Minnesota than Washington!)

I’m not going to go into the nuances of the arguments here — we’ve done it before if you want to check the archives. But what I am going to point out is that a new study in Oregon has shown that bigger trees might help to deter crime. Yet another reason for the people of this country to demand larger stock.

Despite what all of the research shows (that it’s better to plant smaller trees — preferably bare-root) people want big trees — they want an instant landscape. They want it because to them it looks nice — and now its a way to protect your family too.

Historically this big stock comes B&B and is very expensive, cumbersome, and not the easiest things to successfully plant. We need a new, cheaper way to grow large stock. A number of researchers are working on different methods to produce large stock (special containers, bare root from a gravel bed) but nothing has worked out perfectly yet. It’s going to be interesting to see how all of this shakes out in the future — especially with the loss of ash trees in the Midwest.

What’s In A Name

Marketing is important if you want to sell something, but I have always been amazed at the different names that chemical companies have come up with for pesticides. Way back when, in the early 1900s and late 1800s insecticides were given soft, gentile names. Paris Green, London Purple, Bordeaux mix – really beautiful names that hint of worldly knowledge (for the most part they just indicate where the product was originally produced). In the mid-1900s names were more matter of fact: DDT, 2,4 D, 2,4,5 T — These names were indicative of the chemistry of the product being sold. Then professional marketers got a hold of pesticides and the fun started. If you’ve never farmed then you may never have seen some of these names, but to a farmer who uses commercial pesticides many of these names will sound familiar. My favorite name for a pesticide is Scythe. I don’t know why, it just strikes me as amusing that a chemical is being compared to a hand tool. Maybe Shovel, Rake, or Tweezers is next.

Here are a few names for various insecticides which include the same active ingredient, cypermethrin – a relatively dangerous insecticide — along with some of the emotions which you may feel while considering what insecticide to buy – in other words, feelings that marketers may use to drive you to select one product rather than another:

If you feel like attacking the insects: Ammo

If you’re feeling like the insects are closing in on you: Barricade

If you’re feeling like insects are closing in on you AND you’re a Civil War buff: Stockade

If you’re feeling like bailing out of the farming business altogether: Ripcord

If you want a pesticide that sounds safer than it is: Super

If you feel tough because you just watched the governor of California in an ‘80s sci fi flick: Cymperator

If you’re feeling mad as hell at those nasty insects: Demon

Okay – all of these products aren’t used for the same things, but dang….how many names can you have for one active ingredient?

Oh Deer! Part 2

Last week Holly and I extolled the virtues of our dogs for helping to keep our gardens and landscapes relatively deer-free even though we live in areas with high deer pressure. Of course, letting dogs roam your property is not an option for everyone. So what are some other options to keep deer from turning your garden into a salad buffet?

My former grad student, Sara Tanis, shows off deer damage at her parent’s place near Ludington, MI

One of the most popular non-canine deer remedies is applying various deer repellants. Typically I’ve been pretty skeptical of deer repellants. Trying to stop hungry deer from chowing down on your garden is like trying to stop a high school football team from devouring an all-you-can-eat pizza buffet. Recently, however, I saw some results from some colleagues at North Carolina State University on the effectiveness of various deer repellents in Christmas tree plantations that looked promising. Deer damage is a major issue in Christmas trees; deer browse pressure can be very high on conifers since they may be the most palatable thing available to deer in the winter. Research at NCSU and other studies (Wagner and Nolte 2001, Wildlife Soc. Bull.29:322-330) indicate that repellants that contain putrescent egg solids or animal protein can be effective at reducing deer damage. Of course, no repellant is 100% effective. If they’re hungry enough and don’t have an alternative, deer will likely overcome their fear of these scents and still come in for a nibble. Also repellants need to be re-applied periodically to be effective. Nevertheless, for gardener’s at their wit’s end and ready to resort to high velocity lead, repellants may be a better alternative. Although Sara says lead works too!

When history and good stewardship collide

One of my colleagues emailed me a couple of pictures last week taken in Puyallup, WA. As you can see, there’s a trellis supporting a massive old trunk…

…and crown…

of an ancient Hedera helix ‘Baltica,’ a cultivar of English ivy.

For those of you not in Washington or Oregon state, English ivy is a designated noxious weed. Thousands of dollars and hours of labor are spent on removing this species from forested areas in Washington state, where it crowds out native species and increases tree failure simply through the weight of vegetation. It is not a well-mannered ornamental in our climate.

So why, you may ask, is this particular English ivy prominently displayed and obviously cultivated? Chris Pfeiffer (my colleague) found out that it had been planted by Mrs. Ezra Meeker, wife of the founder of Puyallup, over 140 years ago at their original homestead. It is part of Puyallup’s cultural history and is considered a heritage “tree.”

But as you can see in the second photograph, the ivy is in flower and presumably will set seeds, thus contributing to the invasive problem. I don’t know enough about the City’s management plan for this specimen, but I doubt it includes removal of the flowers before seed set.

So what should communities do in situations like this? I think the city needs to remove the flowers, though this would be a labor intensive activity. But it would only take one person a few hours to hand prune the flowers.

I’ll be curious to hear what you all think, and whether you have seen similar collisions between historical significance and appropriate plant choices.

Confessions of a Weather Channel Addict

My name is Bert and I’m a Weather Channel junkie. It started innocently enough; sneaking an occasional peek at the local radar. Then I found myself sticking around for the next Local on the 8’s just for the smooth jazz. The progression from there was steady and predictable: Glued, trance-like, to the couch for re-runs of ‘Storm Stories’ and ‘When Weather Changed History’; setting my alarm 20 minutes early to catch ‘Wake up with Al’ so I could get my morning Stephanie Abrams fix. My downward spiral was further enabled by weather.com. I knew I needed help when I found myself checking the local radar to see if it was raining instead of just looking out the window.
Admit it. If you’re a gardener or work with gardeners, you’re probably hooked too. Hard to imagine a Saturday or Sunday morning that doesn’t start with tuning in to TWC or clicking on weather.com. The local radar and weather warnings, of course, are indispensible. We had a frost advisory in our area last night and I’m sure some folks will get an extra couple weeks out of their annuals if they paid attention and got them covered.

An often-overlooked feature on weather.com that I encourage gardeners and landscapers to use is the wind forecast. If you go to your local hourly forecast and click on ‘details’, it provides an hour-by-hour forecast for local wind conditions. This is a great way to plan any herbicide applications (e.g, Round-up or Weed-B-gone) you may be contemplating. Doing a little planning and spraying when conditions are calm is one of the best ways to avoid off-target injury.

So clearly there are plenty of reasons to keep us hooked and tuning in, even if some aspects of TWC are getting just a little too predictable:

Studio anchor: And now we go to Jim Cantore, who’s on the Outer Banks where Hurricane Holly is about to make landfall. Jim, what’s the latest out there?

Cantore (braced against a gale but looking studly in his official Weather Channel raingear): Well, just like the other 73 hurricanes I’ve been in, it’s raining. And the wind is blowing really, really hard!

Cut back to studio anchor: Thank you, Jim, for that insightful report.

The Weather Channel, live by it.

</d

Can cultivars be considered native plants?

One of the questions that arise in discussing native plants is the question of whether ornamental cultivars (e.g., ‘October golory’ red maple) can or should be considered ‘native’. In short, my answer is ‘No.’

Here’s my rationale on this. First, when we think about natives we need to put political boundaries out of minds and think about ecosystems. Political boundaries – a ‘Michigan native’ or ‘an Oregon native’ – are meaningless in a biological context. What’s important is what ecosystem the plant occurs in naturally. In addition to taking an ecological approach to defining natives we also need to consider its seed source or geographic origin. Why is it important to consider seed origin or ‘provenance’? Species that occur over broad geographic areas or even across relatively small areas with diverse environments can show tremendous amounts of intra-species variation. Sticking with red maple as an example, we know that red maples from the southern end of the range are different from the northern end of the range. How are they different? Lots of ways; growth rate, frost hardiness, drought tolerance, date of bud break and bud set. Provenances can even vary in insect and disease resistance.

Native range of red maple

If we’re dealing with an ornamental cultivar, do we know the original seed source or provenance? Sometimes yes, sometimes no, sometimes maybe. Think for a minute how most ornamental cultivars come to be. Some are developed through intentional crosses in breeding programs. The breeder may or may not know the geographic origins of the plants with which they are working. Or they may produce interspecfic hybrids of species that would not cross in nature. Some cultivars are identified by chance selection; an alert plantsperson finds a tree with an interesting trait (great fall color) in the woods or at an arboretum. They collect scion wood, propagate the trees and try them out to see if they are true to type. If the original find was in a native woodlot and the plantsperson kept some records, we may know the seed source. If the tree was discovered in a secondary location, such as an arboretum, it may not be possible to know the origin.

So, if a breeder works with trees of known origin or a plantsperson develops a cultivar from a chance find in a known location AND the plants are planted back in a similar ecosystem in that geographic area, we can consider them native, right? As Lee Corso would say, “Not so fast, my friend.” We still need to consider that matter of propagation. Most tree and shrub cultivars are partly or entirely clonal. Cultivars that are produced from rooting cuttings; for example, many arborvitae, are entirely clonal. Cultivars that are produced by grafting, like most shade trees, are clonal from the graft union up. The absolute genetic uniformity that comes from clonal material is great for maintaining the ornamental trait of interest but does next to nothing to promote genetic diversity within the species. From my ultra-conservative, highly forestry-centric perspective, the only way to consider a plant truly native, it needs to be propagated from seed and planted in an ecosystem in the geographic region from which it evolved. Few, if any, cultivars can meet that test.

The New Evidence Against Glyphosate

This past week Susan over at Garden Rant asked me about a paper which she had recently read which “proved” that Round-up caused birth defects. This study was interesting because it took embryos of chickens, exposed them to glyphosate (the active ingredient in Round-up) and then looked at the problems which the embryos had. Indeed, there were problems at concentrations of glyphosate much lower than what you’d see in normal agricultural applications. This is similar to other studies which “prove” how toxic glyphosate is which have been conducted over the years where various types of cells have been removed from human bodies, exposed to glyphosate, and then the resulting cellular damage has been taken as an indication that this herbicide is incredibly dangerous to us.

Studies where embryos or cells removed from the human body are tested against poisons have a glaring weakness which needs to be appreciated before we go off the deep end thinking that they prove that glyphosate is killing us. They’re conducted in a system that isn’t at all natural. That’s not to say they have no importance, but it’s like saying that, because it’s known that an air bubble in your bloodstream will kill you, air is dangerous. Or like saying that, because salt injected into your bloodstream is deadly, you shouldn’t eat it. Both air and salt can be deadly if they are in your bloodstream above a certain level, but we need to be careful to look at the specific situation with which we are dealing and take that into account when we make our judgments about how toxic particular things are to us.

I can’t argue that glyphosate can be toxic to people. This morning I did a little literature search on it and actually found cases where people had committed suicide by drinking agricultural formulation of glyphosate – mostly in the Eastern world. It would be a nasty way to go too – you’d need to ingest a lot of the stuff and the primary problems would be that parts of your gastrointestinal system would be corroded. Ouch!

If you’re going to use a glyphosate herbicide use it carefully and in accordance with its label. Don’t go splashing it around willy-nilly. Don’t drink it. Don’t get it on anyone. Don’t use more than you need to. To do any of these things is not only dangerous, it’s also stupid. That said, I can’t find any reason to think that glyphosate is anything but what it appears to be – an effective weed killer that is on the safer end of the spectrum relative to other chemical weed killers (and here I’m including organic weed killers too – Ever been exposed to those 20% acetic acid vinegar herbicides? I tried one this summer — Just being near it made my eyes burn.)