Ward Upham: Extension Blog Contributor Extension Associate – Home Horticulture Rapid Response Coordinator
& Extension Master Gardener Coordinator
Kansas State University Extension
wupham@ksu.edu
Apple trees that are not pruned for several years will often produce so many branches that very little energy is left for fruit production. Overgrown apple trees are also difficult to harvest and spray. Gardeners who have such a tree are often at a loss as to how to get it back in shape.
Often the best (tongue-in-cheek) recommendation s for such a tree is to make one pruning cut at ground level and start over with a new tree. However, trees may have sentimental value that will make revitalization worth the time and effort. Realize that this will be a multi-year process because no more than 30 percent of the tree should be removed in one year. Here are some steps to follow:
Remove all dead wood. This does not count toward the 30 percent.
Remove suckers from the base of the tree.
Choose approximately six of the best branches to keep as scaffold branches. Remove all others. Branches should be cut flush to the branch collar. The collar is that natural swelling that occurs where a branch connects to the trunk or to a larger branch. Removing the collar would leave a larger wound that would take additional time to heal. Do not paint wounds. Research has shown that wounds heal more quickly if left open. Candidates for removal include branches with narrow crotch angles, which are more likely to break in wind and ice storms, and those that cross branches you will save. This may be all that is possible the first year if the 30 percent threshold has been reached.
Thin the branches on each scaffold branch. Remove crowded branches to open up the tree to light and allow humidity to escape. Shorten each scaffold branch by cutting back to a side branch. When you are through, the tree should have enough wood removed so that a softball can be thrown through the tree.
Severe pruning often will cause an apple to tree to produce vigorous side shoots from the trunk, called water sprouts. Main branches will also produce suckers that grow straight up. The suckers and water sprouts should be removed throughout the growing season so the center of the tree stays open.
In the case where a tree cannot be saved but you would like to preserve the apple tree variety, consider grafting. Scions taken from the old tree can be grafted onto a new rootstock to form a new tree. If you are not able to do so yourself, contact a local fruit tree nursery to find someone who may be able to help.
John Porter: Extension Blog Contributer Extension Agent, Ag and Natural Resources
West Virginia University John.porter@mail.wvu.edu
There’s been much ado in the press and on social media about the use of Genetically Modified Organisms (GMOs) in the food system. While there is a scientific consensus on their safety, many still reject their use. While the controversy rages on, an innocent bystander has taken fire, mainly from the spread of misinformation on social media. It seems that simple hybrids, produced through a selective, yet natural, breeding process have been mislabeled as genetically modified. These misinformation sources point to heirlooms as the only non-modified (and thus safe) source of food. The thought is that since the development of a hybrid is directed by humans, they are genetically modified. This simply isn’t the case.
The truth of the matter is that all of the food crops that we plant have been modified at some point in history through human intervention, whether purposeful or not. The simple act of seed saving is a selective breeding process selecting for the best and the tastiest. So even heirlooms are modified through human interaction. The comparison of a hybrid to a GMO is starkly false. I once saw someone explain it this way: breeding a hybrid is like crossing a beagle and pug, making a GM crop is like crossing a potato and a fish. While it is a simplistic comparison, it does make it a little easier to understand.
Many of the heirlooms we now have today were developed by breeders over the last century or so. No one man had such an impact on agriculture as Luther Burbank, who was a prolific plant breeder and a well-known national hero. However, in today’s anti-science fervor, would he be considered more of a villain than a hero? That was the topic of one of my recent newspapers articles. Read more about Luther Burbank, 19th century garden hero.
When diseases occur in urban landscapes, it is often presumed that fungicides are the most important and effective disease management tools available. However, a good sanitation program can help reduce the need for chemical controls and can improve the effectiveness of other practices for managing disease. This often-overlooked disease management tool reduces pathogen numbers and eliminates infective propagules (inoculum such as fungal spores (figure 1c) , bacterial cells; virus particles; and nematode eggs) that cause disease.
Figure 1a. Marigold blossom infected with Botrytis Figure 1b. Pathogen levels can build up on marigold flowers if diseased tissue is left in the landscapeFigure 1c. Infecting spores on plant surface
Certain foliar fungal and bacterial leaf spots can become prevalent during rainy or humid growing seasons. When disease management is neglected, pathogen populations build-up and continue to increase as long as there is susceptible plant tissue available for infection and disease development (Figures 1a-c). Infected plant tissue infested soil and pathogen inoculum all serve as sources of pathogens that can later infect healthy plants.
Figure 2. Fallen leaves can serve as a source of inoculum (fungal spores) for additional infections. Many pathogens overwinter in fallen debris and then produce infective spores the following spring.
Reduction of pathogens by various sanitation practices can reduce both active and dormant pathogens. While actively growing plants can provide host tissue for pathogen multiplication, dead plant material (foliage, stems, roots) can harbor overwintering propagules for months or years (Figure 2).
These propagules can travel via air/wind currents, stick to shoes or tools, or move with contaminated soil or water droplets. Thus, prevention of spread of pathogens to healthy plants and the elimination of any disease-causing organisms from one season to another are the foundations for a disease management program using sanitation practices.
Sanitation Practices
Elimination and/or reduction of pathogens from the landscape results in fewer pathogen propagules. The following sanitary practices can reduce amounts of infectious pathogens:
Figure 3a. Cankers are common overwintering sites for disease-causing pathogens
Remove diseased plant tissues from infected plants. Prune branches with cankers (Figure 3a) well below the point of infection (Figure 3b). Cuts should be made at an intersecting branch. Rake and remove fallen buds, flowers, twigs, leaves, and needles.
Figure 3b. Remove infected branches, making cuts well below points of infection
Disinfest tools used to prune galls and cankers. Cutting blades should be dipped into a commercial sanitizer, 10% Lysol disinfectant, 10% bleach, or rubbing alcohol between each cut.
If using bleach, rinse and oil tools after completing work, to prevent corrosion.
Discard perennial and annual plants that are heavily infected and those with untreatable diseases (e.g. root rots, Figure 4; and vascular wilts). Dig up infected plants to include as much of the root system as possible, along with infested soil.
Figure 4. Heavily infected plants or those with untreatable diseases, such as black root rot (images left and right), should be removed from the landscape.
If infected plants are to be treated with fungicides, prune or remove infected tissue (flowers, leaves) and debris to eliminate sources for spore production or propagule multiplication. This should be done before fungicide application. Fungicide effectiveness may be reduced when disease pressure is heavy, which can result when pathogen levels cannot be reduced sufficiently by chemical means (fungicides).
Discard fallen leaves, needles (Figure 5), prunings, and culled plants. Never leave diseased plant material in the landscape, as pathogens may continue to multiply by producing spores or other propagules. Infected plant material should be buried, burned, or removed with other yard waste.
Figure 5. Black fruiting structures of the pine needlecast pathogen contain spores (images left and right). Removal of infected plant tissue helps reduce amounts of inoculum in the landscape.
Do not compost diseased plant material or infested soil because incomplete composting (temperatures below 160˚ F) may result in survival of propagules.
Homeowners should be cautious about storing diseased limbs and trunks as firewood or using the woodchips as mulch. For example, wood from trees infected with Dutch elm disease should be debarked before placing in a firewood pile.
Remove weeds and volunteer plants to prevent establishment of a “green bridge” between plants. A green bridge allows pathogens to infect alternate hosts until a more suitable one becomes available. Be sure to remove aboveground parts AND roots.
Soil from container-grown plants should not be reused from one season to the next because pathogens can survive in soil.
R.K. Jones, North Carolina State University (Fig. 1A), courtesy Bugwood.org
M.C. Shurtleff, University of Illinois (Fig. 1B), courtesy Bugwood.org
David Cappaert, Michigan State University (Fig. 1C), courtesy Bugwood.org
Theodor D. Leininger, USDA Forest Service (Fig. 2), courtesy Bugwood.org
Joseph O’Brien, USDA Forest Service (Fig. 3, right), courtesy Bugwood.org
Elizabeth Bush, Virginia Tech (Fig. 4, left), courtesy Bugwood.org
Bruce Watt, University of Maine (Fig. 4, right), courtesy Bugwood.org
Andrej Kunca, National Forest Centre, Slovakia (Fig. 5, left), courtesy Bugwood.org
Robert L. Anderson, USDA Forest Service (Fig. 5, right), courtesy Bugwood.org
John R. Hartman, University of Kentucky (Fig. 3, left)
I’m not sure we’ve ever been quite so ready for the calendar to turn to March. That’s assuming, of course, you live somewhere east of the Rockies. For people on the west coast, the sentiment is probably, “When are those people back East ever going to quit b-tching about their weather…” While I was dealing with 10” of snow and 25 mph winds whipping up 3’ deep drifts on Super Bowl Sunday, my friends back home in Washington state were mowing their grass. At this point I don’t even remember what my lawn looks like.
I have to confess that I thought winter 2014 was an anomaly and that we wouldn’t see weather that cold again any time soon, if ever. Boy, did I get wrong number. While winter 2015 is not exactly a carbon copy of 2014, I’m not sure most of us can tell the difference. In case dealing with sub-zero wind-chills for weeks on end wasn’t torture enough, I dug into the weather records from our automated Michigan EnviroWeather network to see how the past couple of months stacked up. To keep things simple I queried the records for the past twenty Januaries and Februaries. I just include those months since we don’t have any data for this March yet and those are the months we typically get our coldest weather, though we occasionally also get sub-zero in late December.
Over the last 20 years the past two winters have been by far the coldest, and it’s not even close. Over the previous 18 years the average daily low temperature for January and February was 17.0 deg. F. In 2014 the average low was 5.9 deg. F; this year it was 5.8 deg. F. Daily low temperatures in Jan. and Feb. of 2014 and 2015 were more than 11 degrees below the average of the previous 18 years.
Not only was it colder on average but we’ve had more extreme cold events in the past two years as well. Between 1996 and 2013 we averaged less than one day per year with low temperatures below -10 deg. We were below -10 deg. F on eight days this winter and nine days last winter. The bottom end of our USDA Hardiness Zone 5 is -15 deg. F. We have been below that mark five times this winter, compared to twice last year and zero times in the previous 18 years.
Over the past 20 years we rarely dipped below -10 F. We’ve been colder than -10 seventeen times in the past two winters.
Obviously this data is specific to mid-Michigan, but I suspect most locations in the Midwest and Northeast will have similar stories to tell. So what does all this mean? For one, our hardiness zones are what they are for a reason. Folks that like to ‘push their zones’ (you know who you are), have gotten away with it with impunity for nearly 20 years. This winter and last were time to pay the piper. The owner of this Cedrus deodora ‘Polar winter’ (zone 6) had gotten away with pushing their zone for 10 years before things came to grinding halt in 2014.
The other take home lesson is that climate doesn’t consistently move in one direction. Even if we’re in a period of general warming, extreme events will still occur. This is important to remember as we think about planning for projected future climates. We have seen the appearance of several climate-change friendly plants lists. In some cases the authors have simply looked at projected climate zones and moved plant selections northward. The problem with this approach is tree survival is based on extremes, not on averages.
Winter appears to have a death grip on the eastern half of the U.S. for the second year in a row. The thermometer on my car read -6 F on my way into work this morning; with lows of -5, -11, and -2 predicted for the latter half of the week. And to my Northwest friends that have been out mowing their grass already, may the bird of paradise fly up your nose. At this point I don’t even remember what my lawn looks like.
Evergreen conifers provide one horticultural escape from the winter blahs. But evergreens don’t have to be green. One group of conifers that can brighten up a winter landscape are yellow or golden conifers. I will acknowledge these plants are not for everyone. But when sited properly (avoid winter sun is a common admonition among conifer buffs) and used judiciously (a little yellow goes a long ways) these conifers can add a contrasting element that can set off a garden. Note: Hardiness zone and size based on the American Conifers Society Conifer database.
Picea orientalis ‘Skylands’ (Skylands Oriental spruce) Zone 4. Size: Large (> 12” per year). This tree is a guaranteed show stopper. The combination of the narrow upright form and golden needles is tough to beat.
Picea orientalis ‘Firefly’ (Firefly Oriental spruce) Zone 4. Size: Intermediate (6’-12” per year). Firefly was selected as a sport off of ‘Skylands’ and is a recent introduction from Iseli nursery. So if you like Skylands but don’t have room for large conifer, this could be for you.
Chamaecyparis pisifera ‘Filifera Aurea’ (Golden thread false cypress) Zone 5. Size: Intermediate (6”-12” per year). This a tough plant that can make a good contrast specimen or can also serve as a foundation plant.
Golden thread false cypress as a foundation planting at the Missouri Botanical Garden
Picea pungens ‘Lutea’ (Golden Colorado spruce) Zone 4. Who says blue spruce have to be blue? Lots of concerns with blue spruce in the Midwest these days (more on that in later posts), but if you’re in an area where blue spruce are still doing well, this is an option for a winter bright spot.
Pinus contorta ‘Taylor’s sunburst’ (Taylor’s sunburst lodgepole pine) Zone 3. Ok, I’m cheating a bit here – the yellow comes on the new growth in the spring and then turns green. ACS database lists as a large conifer but I think they are referring to the straight species. When I have seen this plant it’s more in the intermediate range (6” – 12” per year).
William H. McCaleb, Blog Contributor
Program Assistant for Agriculture and Natural Resources, Halifax County, VA. and Master Gardener
For gardeners in the eastern U.S., last year was a better than normal gardening season. Better than normal yield, better than normal precipitation, and in our case in Virginia cooler than normal which yielded excellent spring cool season crops as well as early summer crops.
But all good things must come to an end; that being the result of several heavy frosts. With that said, I am looking forward to next year’s challenges and what I want to grow for our family. Oh, for the taste of one more summer ripened tomato, but for now, that is a dream and it is time to reflect on what grew well in the garden as well as what didn’t do so well. Hopefully you have kept a garden journal to help you in this task. I find that writing down details of what is planted, the orientation, spacing, fertilization/liming rates and frequency, weekly rainfall amounts, production amounts, etc. is helpful as you start planning for the next season.
Like me, you should start thinking about what you want to grow in 2015. Take time to reflect on your 2014 garden production, care, and location. Also, evaluate what went right and what went wrong with the plants and varieties you planted and harvested. This will start you off in the right frame of mind in preparing for the next growing season. Good planning and preparation for next year gives you the tools to have an even better gardening season. A successful vegetable gardener is a happy well fed gardener!
I know, you too are already missing those fresh tomatoes, potatoes, peppers, squash, okra, and other great home grown vegetables we treated ourselves to this year, but the next season is ‘just around the corner’ so to speak. After all the days are getting a little longer. Spring can’t be far away!
If you just happen to live in an area that hasn’t had frost yet, take your prompt from your plants: when annuals and seasonal vegetables turn brown and begin to die back, it is time to clean up your garden.
Clean up the Garden Your best action is to remove any spent or failing plant materials. Experienced gardeners know that many of the bacteria, fungi, and other disease-causing organisms that caused those diseases. Pathogens that are sources of those diseased plants this past season can survive over the winter in dead leaves, stems, roots, and dropped fruits that get left in the garden. Much like a piece of bread that is kept too long and looks like it has penicillin growing on it, garden debris also will carry the pathogens that can come alive with those same problems when the temperatures begin to rise in the spring. Prevention of diseases and insect infestation now, will keep you from a repeat of problems in next year’s garden.
A good leaf rake, given enough ‘elbow grease’, works well in getting the bulk of dead plant material out of your garden. If you experienced early or late blight or other tomato related diseases this past growing season, you want to make sure you reduce, to the best of your ability, the risk of repeating that problem again next year. Yes, there are many new varieties of vegetables available today that are ‘resistant’ to some of these diseases, but ‘resistant’ does not mean they are immune to them. You don’t want to take the chance of returning pathogens, so do a good job, cleaning and ‘sanitizing’ your garden now. Make sure, when removing the plant debris, that you totally destroy that debris so that no pathogens are left behind.
To Compost or Not! Can you compost this dead plant material and use it next spring? Information that you find from Extension offices across the U.S. will recommend that you do not. The reason being is that most people do passive composting i.e. put it in a pile, and then using what compost develops, put the compost back in the garden for the next season. It is best to burn the plant material; this will destroy the pathogens and weed seeds as well and return some carbon back into the ground when you spread it out. Please check local/state laws prior to burning. Many states and/or localities have burn bans especially this time of the year. Another method, if your local law allows it you can bag the material and send it to the landfill. Each year there are more localities that ban yard waste from their landfills. If you are not sure, check with your locality to learn more about your local waste and recycling laws.
If you do decide to go with active composting; composting at a temperature 140°F, or higher, will destroy many of the disease organisms as well as many weed seeds. You will need a temperature probe to monitor compost temperatures. It’s really not hard to source a compost thermometer either through the internet or local retail outlets such as garden centers or nursery supply stores. If in doubt about your compost pile reaching these high temperatures, it is best to side with caution and discard the material by properly bagging it or by burning based on your local ordinances.
Preventing Overwintering Pathogens Some of our most notorious insects of the garden such as Mexican bean beetle, squash vine borers, European corn borer, cabbage loopers, can also overwinter in garden debris. Larvae will use debris as a safe harbor. Flea beetles and spider mites, as well, can find food and winter shelter in spent plant material and weeds.
After you have finished cleaning up the debris from your garden, it is time to turn over the soil to both aerate and break up any remaining debris into smaller pieces that will be turned under. A good rototiller will help make this job easier. Once buried, any plant material left will decompose more rapidly.
For some pests and pathogens, turning over the soil after removing spent plant materials is recommended as the main line of defense against overpopulation next year. Consider this information from “Home and Horticultural Pests: Squash Bugs and Squash Vine Borers,” from Kansas State University,
“A vigorous autumn… rototilling can physically destroy cocoons and larvae (of the squash vine borer). Brought to the surface, cocoons and larvae are more susceptible to predation by birds and exposed to cold winter elements, leading to their demise. Deep plowing physically destroys cocoons and larvae burying them deep beneath the soil surface so pupated moths become entombed underground.”
Steps to a Healthier Garden If you haven’t done a soil test in three years or more, it is time to retest and determine the needs of your garden soils based on what you will be growing in the next season. Soil test kits and instructions are available from your local Extension Office. Also, in planning next year’s garden, rotation of your crops is a must do item. This simple action will help keep disease issues down. If your soil test(s) recommend liming, you can go ahead and put down lime this time of year, allowing it to start adjusting the pH. If the ground is frozen already, wait until spring. As you add lime, you can also help build soil structure by incorporating compost or shredded leaves. These soil additives will also add beneficial micro-nutrients and beneficial organisms. If you want to further build the soil, you may want to consider putting in a cover crop that will not only hold soil, but when tilled in early spring, will further build a healthier garden soil. A legume such as white or red clover would be something to consider. Check with your local Extension Office for best cover crop recommendations for your area.
“Three Sister’s Garden-Fall Clean-up “Southern Virginia Botanical Gardens” Photo by W. McCaleb 10/28/14 Corn, Beans, and Squash was grown here as the native Cherokee have done for centuries. Cleaned up and ready for spring 2015!
I’m usually not much for product promotion or endorsement, but so few people seem to know about these spiffy little Swiss-made nippers, seems deserving of a post. Leyat Sàrl is a long-time manufacturer of sécateurs (I love that word – sounds way more dramatic/awesome than “pruners.” Hee!).
Leyat pruners come in all sizes and are pretty popular in orchard and vineyard circles, but I can’t say I’ve seen them at many retailers. I found an old pair of the little ones and have been toting them around for several years, never quite sure where they came from, thus terrified of losing them. While ordering some power Felcos for our blueberry pruning endeavors (three acres-worth – and that’s another story entirely), the online purveyor also carried these same little pruners I thought I’d never find again.
This is why they’re awesome:
They fit into your pocket and do not fall out.
I do plant walks for i.d. classes and garden tours all the darn time. I’m always grabbing a flower or leaf of whatever I’m talking about, and it’s handy to reach into my back pocket or jacket pocket and nip the stem (versus accidentally yanking the entire plant out of the ground while trying to get the stem to break, which tends to appall students and garden visitors).
I have a shoebox full of Felcos and Coronas, but these are my go-to bypass snips for either the purpose described above, or light work such as deadheading. Of course I’llwhip out the bigger pruners for more challenging tasks.
The stainless steel blade takes well to sharpening, and the bright color helps me keep track of them. I’m not a fan of plastic moving parts, but the little square closure has hung in there on my old pair.
They are in stock on a few online sales sites – my shiny new ones came from The Pruner Warehouse – several bright colors in stock, plus on sale for $16.99.. Sold out now! Guess some folks took my advice. Try www.landscapetools.com – they’re $20.10 though. The official model is “Leyat HLB1 Bypass Pruner HLB1”.
For long-time readers of this blog, you know how much I love arborist wood chip mulches. Now my new WSU Extension fact sheet has just come out – feel free to share it with your gardening friends.
If you value what we do, please take a few minutes to fill out the survey linked below. We’ll leave this open for the month of January but will need to close it then so we can analyze and use our results. Feel free to share this with other gardening aficionados.
Thanks in advance for your interest and support! https://www.surveymonkey.com/s/7R6C6FH
This week one of our Facebook group members posted a link to a 2013 paper entitled “Love thy neighbour: facilitation through an alternative signalling modality in plants”. The premise in the paper is that plants are capable of acoustic communication and the experiment purported to demonstrate this. (I strongly encourage you to download the article from the link above so you can read it for yourself.)
Briefly, chile seeds (Capsicum annuum) were placed into petri dishes, covered to ensure darkness, and then the dishes were placed in a circle. In the middle of the circle was either an empty acrylic box covered in black plastic (the control), an acrylic box covered in black plastic containing an adult basil plant (Ocimum basilicum) called the masked treatment, or an adult basil plant without a box (the open treatment). Seeds were watered and inspected daily for germination and the petri dishes were randomly rearranged.
According to the authors, “the presence of basil positively enhanced germination rates of chilli seeds, validating the claims of many gardeners who recognise the beneficial effect of basil on the growth of chilli plants.” Their reasoning is that the open and masked treatments induced more seed germination than the control. And since there was little difference between the masked and open treatments, they claim that the phenomenon is due to some signal other than light or gas (since the black plastic-covered acrylic container would prevent this).
How does this work? Well, according to the authors, this is evidence that acoustic signals are “generated in plants by biochemical processes within the cell, where nanomechanical oscillations of various components in the cytoskeleton can produce a spectrum of vibrations.” Never mind that the experimental design and methodology was laden with opportunities for experimental error. In particular, opening the petri dishes to water and count germinated seeds every day is deeply flawed. The easiest and least error-prone method would be to have the petri dishes sealed with parafilm to prevent water loss and inspected ONLY after the experiment was over. That is the standard method for testing for germination rates. Moreover, opening the dishes to count and water seeds every day really screws up the “covered to ensure darkness” part. In fact, chile seeds germinate better with light – which is what they got every day when they were opened. Was each dish exposed to light for exactly the same time every day? Exposure to light converts the seeds’ phytochrome to what’s called the active form, and phytochrome plays a crucial role in seed germination. The longer the light exposure, the more phytochrome is converted.
Now, plant scientists would know these things when they were designing their experiments. But as neither of the authors have degrees in plant sciences, it’s understandable. What’s not understandable is how this article got through peer-review. Unless none of the reviewers were plant scientists, either.
For those of you that belong to a university journal club or some other science discussion group, I think this would be a great article to discuss.
