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David Zlesak“Oh no, are my rhododendrons dying?” or something similar is a startling thought that comes to mind the first time many of us see this characteristic curling on leaves of our rhododendrons in winter. Fortunately, this is a normal response called thermonasty that actually helps our rhododendrons survive this difficult time of year. This curling and drooping of the foliage is in response to cold temperatures (thermo= heat or temperature and nasty= movement to a stimulus that is non-directional). As temperatures warm and cool during winter we can actually observe rhododendron leaves appearing less or more drooped and curled. As a broadleaf evergreen, the large surface area of rhododendron leaves makes them especially vulnerable to drying out during the winter. With the frozen soil this time of year, additional water cannot easily move up the plant and replace what evaporates from the foliage. Curling and drooping to prevent wind from reaching the undersides of the leaves, where stomates (openings for gas exchange) are typically more concentrated, can help prevent wind from drawing out as much moisture. In addition, many rhododendrons are native understory plants in deciduous forests. During the growing season the plants are shaded by the trees above, but during the winter when plants cannot utilize light well, leaves typically experience more intense sunlight capable of damaging exposed leaf tissue. Curling and drooping also aids the plant by reducing the overall amount of light intercepting a leaf. As we are excited for spring to come by this time of year in Minnesota, it might be fun for us as gardeners to look to our rhododendrons for a light hearted way to predict how much more winter we have left than groundhogs and how afraid they are of their shadows!
It’s official. Winter is more than half over. Are you feeling a bit desperate for warm temperatures and the color green? I spend every February dreaming of a trip to anywhere warm and green or of a kinder, gentler Minnesota where spring actually arrives in February. A quick look out of my window though always reminds me of how truly bleak our long winters would be without woody plants.
Imagine our winters without trees. The word “tundra” comes to mind with endless unbroken landscapes and unchecked winter winds. In fact, the word tundra comes from the Finnish word “tunturri”, meaning treeless plain. Now add trees back into the picture and winter, even in February, is not so bad.
Leaves have fallen from deciduous trees and our focus turns to the sheer size and bold architecture of many tree species. White oak (Quercus alba), swamp white oak (Q. bicolor), bur oak (Q. macropcarpa), red oak (Q. rubra), northern pin oak (Q. ellipsoidalis), and black oak (Q. velutina) are native and abundant in Minnesota, and their large size and gnarled branches add interest to a winter landscape (Figure 1). Weeping willows (Salix sp) with their height and dramatic yellow weeping stems are startling against a blue winter sky (Figure 2). Who can help but notice a female Kentucky coffee tree (Gymnocladus dioicus) this time of year with its coarse branches, textured bark, and large seedpods (Figure 3)?
Evergreen trees add mass and color to our winter landscapes. The view of large, mature white pines (Pinus strobus) and red pines (Pinus resinosa) against snow and bright blue winter skies in eastern or northern Minnesota is an amazing sight (Figure 4). In a planted landscape, spruce (Picea) and fir (Abies) lend a formal air with their conical “Christmas tree” forms (Figure 5). Scots pine (Pinus sylvestris) with its wide crown and horizontal orange branches provides a less formal source of green in winter landscapes (Figure 6). Austrian pine (Pinus nigra) with its stout trunks, branches, and dark green needles adds a strong sense of mass to our winter landscapes (Figure 7).
Step in for a closer view of our winter landscapes and you will see texture and color everywhere. With leaves absent, the large flower buds on silver maple (A. saccharinum), red maple (A. rubrum), and Freeman maples (Acer x freemanii) give branches a beaded look. Nothing shouts texture like the cinnamon and ivory curling bark of a river birch (Betula nigra) (Figure 8), the flaky bark of three-flower maple (Acer triflorum) (Figure 9), the brown rustling leaves that are retained during winter on younger oak trees (Figure 10) or dried flower heads of hydrangea (Figure 11). The shiny red-brown bark of Manchurian cherry (Prunus maackii) (Figure 12) is beautiful on sunny or cloudy days. Dwarf conifers come in an amazing variety of form and texture in shades of green, blue-green, and gold (Figure 13). ‘Green Mountain’ boxwood (Buxus sp.), one of the few broadleaved evergreen plants hardy in Zone 4, is still a mass of green leaves in February (Figure 14). Many of our small trees and large shrubs are multi-stemmed plants whose twisting trunks and/or retentive fruit are full of texture and color: blue beech (Carpinus caroliniana) with its gray fluted stems (Figure 15), sumacs (Rhus sp.) with their red fruit (Figure 16), Amur maples (Acer ginnala) full of brown samaras (Figure 17), redbuds (Cercis canadensis) with seedpods, and tree lilacs (Syringa reticulata) with their masses of open brown seed capsules (Figure 18). We know crabapples (Malus sp.) for their beautiful and fragrant spring bloom, but many crabapple cultivars (‘Adams’, ‘Bob White’, ‘Centurion’, ‘David’, ‘Donald Wyman’, ‘Harvest Gold’, ‘Indian Magic’, ‘Ormiston Roy’, ‘Professor Sprenger’, ‘Red Jade’, ‘Red Jewel’, ‘Red Splendor’, ‘Sentinel’, ‘Silver Drift’, ‘Silver Moon’, ‘Sugar Tyme’,) retain their red, orange, and gold fruit through winter, adding color to gray winter days (Figure 19). European cranberrybush (Viburnum opulus) and our native American cranberrybush (V. trilobum), winterberry (Ilex verticillata), and barberries (Berberis sp.) also retain fruit through the winter. Masses of these vivid orange and red fruit are beautiful against a snowy backdrop (Figure 20). Red or chartreuse stems of our dogwoods (Cornus sp.) are another source of bright color during winter (Figures 21 & 22).
Step up to trees and shrubs during your winter strolls for a bird’s eye view and more winter interest awaits you. Have you ever looked closely at the branches of our ornamental cherries, plums, and almonds? The branches and trunks of these plants, all of which are members of the genus Prunus, are often covered with conspicuous lenticels (Figure 22), openings that allow gas exchange between the inner parts of plants and the atmosphere. The green stem of a burning bush (Euonymus alatus) edged with brown corky ridges is full of interest (Figure 24)as is the colorful fruit of a bittersweet vine (Celastrus scandens) wrapping around a pillar (Figure 25). The blue or violet berry-like cones of junipers (Juniperus sp.) (Figure 26)and the cones of pines (Pinus sp.), spruce (Picea sp.), fir (Abies sp.), arborvitae (Thuja occidentalis), andDouglasfir (Pseudotsuga menziesii) against a backdrop of green needles or scales are full of color and contrast (Figure 27). How about the beautiful texture, color, and softness of a fur-covered Magnolia (Magnolia sp.) bud (Figure 28)? It’s almost as if each bud has its own winter parka. Look at the buds of lilacs (Syringa sp.). They are plump and green, appearing as if they will open tomorrow (Figure 29). The male flowers or catkins of birch (Betula sp.) trees and their relatives are visible all winter, providing a light texture in plant canopies (Figure 30).
Look out across a vista, look up into a tree, or closely into a shrub and you will see that even in winter, our landscapes are packed full of interest. As you plan future landscapes, don’t forget to combine some of these plants into a collection of companion plants. Winter is a long season in Minnesota and a wise gardener plans for garden interest in winter as well as during our warmer months. The contrast of red dogwood stems, green pine needles, and oak leaves is a planting combination full of color and texture in winter (Figure 30) as is a grouping of ornamental grasses, and evergreens (Figure 32).
Since 1990, the Perennial Plant Association (PPA) has sponsored the Perennial Plant of the Year® program. Each year members select a superior performing perennial to highlight and promote. Nominations are made by members and winners are decided by ballot. Criteria for nomination includes it must perform well across a wide range of climates, be widely available and easy to propagate in order to supply demand, be relatively low maintenance and easy to grow so the average gardener has a high likelihood at being successful with it, and the plant displays ornamental appeal over a long portion of the growing season.
The 2009 Perennial Plant of the Year® winner is golden hakone grass (macra ‘Aureola'). The golden-green foliage and soft, cascading habit has made this shade tolerant perennial grass a favorite for years among gardeners. With a limited selection of ornamental grasses that are tolerant of shaded locations, golden hakone grass is a great addition. In these darker, shaded garden locations, the glowing, golden foliage easily stands out, often serving as a great focal point. Plants are clump forming, grow slowly, and do not need frequent division. In fall the foliage can take on pink and bronze tones.
The graceful, arching growth of hakone grass typically reaches a foot or so in height and is commonly used in group plantings or as a border plant with other perennial. It provides a great accent in texture and form and mixes nicely with other common shade-tolerant perennials like hostas. The foliage form is reminiscent of a compact growing bamboo making this grass a nice choice to include in Japanese gardens and gardens in general where one is trying to create an Oriental flavor. The small flowers golden hakone grass produces in summer are not readily noticeable.
The botanical name of this plant (Hakonechloa) is derived from the region in Japan where it is native (Hakon) and the Greek word for grass (chloa). It does best in moderately moist, acidic, well-draining soils high in organic matter and is adapted to openings in forests. Partial shade is best for this plant as full sun can cause some burning and lead to quicker drying out of soils. The deeper the shade, however, the greener the foliage color becomes.
Golden hakone grass is often listed as hardy to zone 5. However, many Minnesota gardeners in zone 4 have been successful with it. It has consistently survived year after year in many Minnesota locations without any special protection. Providing some insulation in more exposed locations and in zone 3 is recommended.
Besides Perennial Plant of the Year® winners, other great performing perennials tested as part of the University of Minnesota Annual and Perennial trials are featured at: www.florifacts.umn.edu
Past Perennial Plant of the Year® winners
2008 Geranium ‘Rozanne’ (not reliably zone 4 hardy)
2007 Nepeta ‘Walker’s Low’
2006 Dianthus gratianopolitanus ‘Feuerhexe’
2005 Helleborus x hybridus
2004 Athyrium niponicum 'Pictum'
2003 Leucanthemum 'Becky'
2002 Phlox panniculata 'David'
2001 Calamagrostis x acutiflora 'Karl Foerster'
2000 Scabiosa columbaria 'Butterfly Blue' (not reliably zone 4 hardy)
1999 Rudbeckia fulgida var. sullivantii 'Goldsturm'
1998 Echinacea purpurea 'Magnus'
1997 Salvia 'Mainacht' (May Night)
1996 Penstemon digitalis 'Husker Red'
1995 Perovskia atriplicifolia
1994 Astilbe 'Sprite'
1993 Veronica 'Sunny Border Blue'
1992 Coreopsis verticillata 'Moonbeam'
1991 Heuchera micrantha 'Palace Purple'
1990 Phlox stolonifera
In February, as winter seems to drag endlessly on, gardeners who just can’t wait to feel some soil between their fingers finally have something to do: start sowing seeds. While many seeds need to be planted just four to six weeks before being moved outdoors, others that are slower to mature should be started 10 to12 weeks before being transplanted. Timing is important because you want your seedlings to be strong enough to manage on their own, but you don’t want them getting so big that they crowd each other and compete for light, water and nutrients.
If you haven’t already got a planting area set up in your basement or other cool, out-of-the-way place, you can easily do that now. Bright windows of course will do, but with the short days this time of year and often limited window space, lights are a great alternative. Be sure to find a spot near a power source so you can plug in lights and any heating elements you may need. Garden catalogs are full of seed-starting systems, but you can save money by building your own. I start my seeds on metal shelving I found at one of the big box stores. Shelving units are nice because multiple layers of plants can be grown in a particular space.
Fluorescent shop lights work great (you usually don’t need spendy grow lights) and can be suspended above each shelf from chains. The chains allow one to adjust the height of the lights as the seedlings grow. Generally, you want to keep them within a few inches of the tops of the plants once they have germinated. Florescent light is much less intense that sunlight and having the lights relatively close to the plants increases the light intensity. Keep lights on at least 14 to 16 hours each day to fuel strong growth. I find it’s easiest to just put them on a timer. Although you can keep lights on 24 hours a day, a dark period is useful to encourage plants to open and close their stomates to help them better acclimate when it comes time to transfer them outdoors.
Plants need, in particular, the red and blue portion of the light spectrum in order to fuel photosynthesis. Cool white florescent bulbs tend to be rich in blue and borderline in red light. So some people like to mix warm and cool white florescent bulbs in order to get additional red light. This rich mix of red and blue light is what makes grow lights look purple. Bulbs differ based on wattage and lumens. The more lumens, the more light. The highest lumens you can typically find for four-foot T12 florescent 40-watt bulbs is about 3,200. Remember that because florescent bulbs contain a small amount of mercury, they are considered hazardous waste. Many cities have designated drop off sites and free disposal of florescent bulbs of all types. Several drop off sites are located in the metro (www.rethinkrecycling.com/residents/throw-buy/household-hazardous-waste-collection-sites)
People recommend all kinds of different containers for starting seeds, including trays and flats, plastic takeout containers, milk jugs, egg cartons. It really depends on personal preference and what works best with your set up. I like to use 12-ounce, clear-plastic cups (the kind you get for beer at a keg party—not that I go to those anymore). These take more growing medium than I would use in a shallow tray, but the advantage is that I don’t have to transplant the seedlings into larger, individual containers once they really start to take off. I just thin them out in their cups, leaving only one or two plants in each.
To start seeds, you want a growing medium that is light (to allow seeds to push their way up through it), porous (to allow proper drainage and aeration) and sterile (to preclude disease). You can buy soilless seed mixes or you can make your own using equal parts peat moss, fine perlite and vermiculite.
Seeds usually germinate best when the soil is warm and moist. Some seedlings need light to germinate while others don’t. Many can be put on top of your refrigerator or another warm spot until they germinate and then moved under lights to continue growing. (Windowsills aren’t a good choice, usually, because they can be cold and drafty this time of year.) Or you can purchase heating mats or cables to place under your plants in your prepared growing area. For most species, after the seeds germinate, it is good to reduce the temperature to help promote sturdy, compact plants.
Directions on the back of your seed packets will usually tell you what you need to know, including how deeply seeds should be planted, how long until germination and whether the seeds need to be treated in any way before planting. These treatments, such as soaking seeds in water, scuffing the seed coat or placing them in a cold environment for several weeks before sowing, are often necessary for successful germination. If there is no recommendation for planting depth, the general rule is to plant seeds two or three times as deep as the seed’s diameter. Small seeds, such as poppy, snapdragon, and flowering tobacco, should be thinly scattered on top of the soil and very lightly covered, if at all. (Germination tips on a wide range of species can be found on this website: http://www.backyardgardener.com/tm.html.)
You’ll want to moisten your potting mix if it is dry before starting to plant. That way, when you water after planting the mix will easily soak up the moisture. As you sow your seeds, be sure to label each container. Trust me, if you think you’ll remember, you won’t. I’ve finally learned my lesson on that one. Once everything is planted, lightly mist the top of the soil with warm water and cover each container with plastic wrap or domes to help keep the seedbed humid and moist. Continue to mist plants, or water very gently, as needed.
Once your plants have emerged from the soil, you can begin to remove the plastic wrap (or plastic cover if you’re using the trays). Keeping seedlings covered will help to keep them from drying out so fast, but be careful the humidity isn’t kept too high. A lot of condensation can put developing seedlings at risk for attack by pathogens. I cover my cups with plastic wrap, leaving the sides somewhat open so air can get in. As plants grow, I use toothpicks or tongue depressors to keep the plastic away from the seedlings. Heating units can also be turned off at this point after germination is complete. If you germinated your seed without much light, remember to turn the lights on and keep them within a few inches of the plants to promote growth and prevent them from stretching.
Check your seedlings regularly so they don’t dry out. Once your seedlings get their first few leaves (their first “true” leaves after the cotyledons), begin to feed them with a water-soluble fertilizer mixed at quarter strength once a week to help fuel strong growth. I like to use fish emulsion, though it is quite smelly. Soon the dreaded time of thinning will come. (I dread it, anyway) Though it feels like killing your darlings, you must thin the crowd in each seed container, leaving only one plant, maybe two, in some cases. Extra seedlings may be transplanted to new containers.
Finally, spring comes and your seedlings are almost ready for the garden. But, first, it’s best to help them get accustomed to outdoor conditions by helping them “harden off.” To do this, you’ll be taking the plants outside to a sheltered spot daily, a little longer each day. After a week or two, they’ll be ready to move to their new homes and you can take a few minutes to write down what worked and what didn’t so you’ll be ready for next year. The hardening off process allows the plants to adjust to higher light levels, wind, and temperature variations. If planted directly outdoors without hardening off, they can become sunburned or otherwise damaged.
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The Right Time to Sow Seeds
When starting seeds, you want to sow them so they’ll be ready to plant after the threat of frost has passed, which is usually around Mother’s Day in Southern Minnesota and Memorial Day in Northern Minnesota. (Unless they are cold-tolerant plants, like pansies, which can go out earlier.) Typically very small seeded plants, such as begonias and snapdragons, need additional time for seedlings to develop in size because seeds do not contain much in energy reserves. Other plants just have a slower initial growth rate than others. Whether your seed packets lack the information you need to determine when to start your seeds indoors, or you’ve collected a bunch of seeds from plants you like and don’t know when to plant them, this chart offers sowing times for several plants gardeners often start at home.
Tracy WalshPreview Event is Feb. 12; Exhibit Opens Feb. 13
Chaska, Minn. (Jan. 8, 2008) – Escape the icy blasts of winter and feast your eyes on some exquisite tropical beauties at the Minnesota Landscape Arboretum’s “Totally Orchids – Delight at First Sight” exhibit, opening Friday, Feb. 13, in the Arboretum’s Oswald Visitor Center.
The orchid show, presented by Orchids Limited of Plymouth and the Arboretum, will feature a wide array of unique species and select hybrids, all arranged in attractive planters on eye-level pedestals. The display will continue through March 8 and is free with gate admission ($7 adults).
Several complementary events are planned during the “Totally Orchids” exhibit. Check out these activities (all free with gate admission unless otherwise noted):
With over 28,000 species and more than 300,000 cultivars, orchids belong to the most diverse family of plants known to man. They are also extremely adaptable – growing in tundra, rainforest, desert and swamps. In fact, more than 45 types of orchids grow natively in Minnesota.
This past summer, many Minnesotans noticed dead brown wilted leaves on apple, crabapple and mountain ash trees caused by the bacterial disease known as fire blight (Read Midsummer Trouble for Trees & Shrubs) Although symptoms of fire blight are most apparent in spring and summer months, one of the best times to manage this disease is right now.
Fire blight is caused by the bacteria Erwinia amylovera. This pathogen can infect all members of the Rosaceae family, but most commonly causes problems on apples, crabapples, and mountain ash trees in Minnesota. In the spring and summer months, the fire blight bacteria infects leaves and blossoms, turning them black to brown. The infection often starts at the tip of the branch and moves systemically downward, resulting in entire branches that look blackened or scorched by fire.
It is within these infected branches that the fire blight bacteria survive Minnesota’s harsh winters. Branch infections are known as cankers and can be recognized by gardeners as an area of the branch with cracked, discolored and sometimes sunken bark. If the bark is peeled back with a sharp knife, reddish brown streaks can be seen in the light colored sapwood of the tree. Healthy sapwood should be off white to light green in color.
In addition it is common for the leaves and blossoms killed by a fire blight infection to remain attached to the infected branch. These are an indicator to gardeners to look more closely at the branch to determine where the branch canker is. Trees that suffered from fire blight in the previous summer should be carefully inspected for cankers regardless if leaves remain attached or not since wind can knock old leaves to the ground.
Any cankers that are found within the tree canopy should be pruned out and destroyed in February and March. During these months, it is too cold for the fire blight bacteria to be actively spreading within and between trees. In spring, as the weather warms up, however, the bacteria will multiply and ooze out of the canker in a sweet sticky liquid. This bacterial ooze is carried to new trees on wind driven rain, by insects, or on pruning tools and the hands of gardeners. It is therefore critical to remove branch cankers before the start of the new growing season to prevent new infections.
Gardeners should make the pruning cut to remove fire blight cankers at least 8 inches below visible signs of the infection. After each pruning cut, tools should be cleaned with a 10% bleach solution, rubbing alcohol, or a household anti-bacterial cleaner like Lysol® or Listerine®. All infected branches should be burned, buried or disposed of in the trash.
This has been one of the coldest winters in Minnesota in 15 years. And while it can be challenging to find many good things to say about this kind of weather, many people take consolation that the cold temperatures are good for killing insect pests. The most common question lately has been whether putting out furniture or other articles in very cold weather will kill bed bugs.
Cold temperatures can kill bed bugs if they are exposed to it long enough and at temperatures that are cold enough. However, there is not a lot research on this topic to say what those exposures and temperatures are. What information is available is contradictory. One researcher in 1966 found that bed bugs can tolerate temperatures around 5o F for a brief time and when acclimated can survive temperatures at or below 32o F for days. This is in contrast to findings in 1991 that bed bugs are killed when exposed to temperatures around 32o F for just hours, although the same article also went on to say that the eggs are very cold tolerant and need to be exposed to freezing temperatures for 30 to 60 days.
There is even less research that looks at how long you need to freeze bed bugs when they are in furniture or other objects. The U.S. military believes that if you expose furniture to 0o F or less for four days or more, that may be sufficient. While we have been at or below 0o F often, those temperatures have generally fluctuated and have infrequently been sustained for four days or more.
There are other factors to consider. First, the temperature where the bed bugs are hiding may not be as cold as you think it is, i.e. the air temperature is not necessarily the same where the bed bugs are located in the furniture. You also need to factor in the effect of the sun shining on any objects. Although the temperature may say 0o F, the warmth of the sun can considerably raise the temperature in localized areas (as recently witnessed by the melting snow on my roof in near 0o F temperatures).
Again, cold can kill bed bugs, but the bottom line is you can not reliably kill all bed bugs infesting objects by exposing them to 0o F temperatures.
However, if you have or are concerned that you have items that are infested with bed bugs, keeping them outdoors will certainly immobilize any that are present until you decide what to do with them. If you have clothes, you can reliably kill bed bugs by washing or drying them at the highest temperatures allowed by the fabric. If you have other items you are not sure what to do with, contact an experienced pest control service for help in eradicating the bed bugs.
Following is a brief report summarizing the results and observations regarding the establishment and growth of selected fine and tall fescue grass cultivars on an environmentally harsh site. It is located in Spring Park, Minnesota on the shores of Lake Minnetonka. Specifically, it is a nearly fully exposed south facing shoreline embankment between the Lake Minnetonka Sheriff’s Water Patrol (SWP) building and the Spring Park public access (PA). The southerly exposure and very poor, sandy to gravelly soil make this an intensely hot and very dry site. There exists a small lilac hedge along the very top (north) edge of the area adjacent to the parking lot. There are also several, poorly formed crabapple, green ash and Russian olive trees located on this site. All are less than 20 feet in height. Information regarding the establishment, longevity and competitiveness of these grasses on this site should be helpful to others managing similar types of sites.
This project was a cooperative effort between the Hennepin County Department of Environmental Services and the University of Minnesota Extension. Project managers from Hennepin County were Anthony Brough and Greg Senst. Regional Extension Educator, Bob Mugaas from University of Minnesota Extension, served as principal investigator for the study with cooperation from University of Minnesota Department of Horticulture Faculty member in turfgrass science, Dr. Eric Watkins.
Nature and Purpose of the Study: Following several unsuccessful attempts to establish permanent, perennial, non-turfgrass vegetation on the above described site, the Hennepin County Department of Environmental Services contacted University of Minnesota Extension for advice and possible assistance in attempting to establish a very low maintenance turfgrass type groundcover on this area. From that request evolved an applied research/demonstration project evaluating whether or not a commercially available no-mow mix of several different fine fescue varieties could successfully be established and maintained on this site. The individual fine fescue varieties contained in the mix would also be evaluated independently in separate plots to assess their individual performance and potential contribution to the success (or failure) of the no-mow mix. Also included in the study was a seeded and sodded example of tall fescue. Seed for the no-mow mix along with the individual fine fescue cultivars and the tall fescue blend was generously donated by Twin City Seed Company. The rhizomatous tall fescue sod was donated by Glen Rehbein Companies. These industry contributions to the project were greatly appreciated.
Project Design and Installation
The specific varieties contained in the no-mow mix were ‘Defiant’ – hard fescue, ‘Celestial’ – creeping red fescue, ‘Intrigue’ – chewings fescue, and sheep fescue for which a variety was not specified. The tall fescue blend included the varieties ‘Millennium’, ‘Aztec II’, and ‘Anthem II’. The sodded cultivar is simply known as Rhizomatous Tall Fescue (RTF). With the exception of the sodded tall fescue, all other varieties were direct seeded April 25, 2006. The RTF sod was installed May 9, 2006. Plot sizes for the individual fine fescue cultivars and the tall fescue plots ranged from 400 to 600 square feet. The area seeded to the no-mow mix was about 1200 square feet in size. Once seeded, all areas were covered with Futerra™ erosion control mats to provide for a more uniform seed germination environment and help prevent soil erosion.
Turfgrass evaluation of the plots included both pictures and notes regarding establishment success, as well as color, density and overall quality of the planting as observed at various times during 2006 and 2007. Ultimately, information regarding the establishment, longevity and competitiveness of fine and tall fescues on very difficult sites was obtained and should be helpful to others considering use of the same plant material in similar situations.
Due to the very hot dry conditions during spring and early summer of 2006, regular watering was provided to ensure adequate moisture for germination and early seedling growth. Watering frequency and amount was significantly reduced during July, 2006 and eventually eliminated during August, 2006. Again, this practice was adopted in an effort to move toward minimal maintenance inputs on this site.
As this was a spring seeding, the potential for annual weeds to germinate, grow and potentially outgrow and out-compete the desirable grasses was high. Hence, regular mowing at about 3.0 to 3.5 inches was carried out through the middle of August, 2006 in an attempt to provide some level of weed suppression without resorting to the use of an herbicide. No further mowing was done on this site for the duration of the observation period as the ultimate goal was to have this be a no-mow area. An application of a broadleaf herbicide in the fall of 2006 was used to control developing perennial broadleaf weeds. No additional herbicides for either annual or perennial weeds were used in 2007.
A turfgrass starter fertilizer was applied at the time of seeding. Also, plots did receive an application of nitrogen fertilizer at the rate of 1 pound of N per 1000 square feet in late October of both 2006 and 2007.
Results and observations summary
Futerra™ mats provided good protection from soil erosion and likely contributed to better initial establishment through greater uniformity of the seed germination environment. Supplemental irrigation can be extremely important in the early growth, establishment and even survival of spring seeded turfgrass. It can also be a means of moderating the effects of high temperatures. In this instance, the consistent watering provided by Hennepin County staff allowed for uniform germination and early growth of the seedlings thereby getting them off to a good start in spite of the prevailing hot, dry conditions during late spring and early summer. Where irrigation cannot be provided, the use of erosion mats such as those used in this study may play an even more important role in successful early turfgrass growth and establishment, especially for spring seeding.
Given the harsh conditions of poor soil and extreme exposure on this site, the fine fescues under a no-mow situation performed acceptably well and could be considered a good choice for providing soil stabilization and an appealing look to the area. However, one notable caveat is that in the full sun exposure of the southernmost 1/3 to 1/2 of the plots, some dieback of the fine fescues did occur. This was most likely due to the combination of high temperatures and dry conditions. This amount of injury would likely create the need for overseeding in order to preserve turfgrass density and limit future weed encroachment. For the purposes of this study, overseeding was not performed.
Where plots included some partial shading of the fine fescues, their performance was significantly better than on the more open, exposed portions. That observation is consistent with previously known information about fine fescues and reaffirms their successful adaptation to drier, partially shaded areas of the landscape (please see the last photo in the article).
In an effort to keep annual broadleaf weed competition from becoming excessive, mowing at about three inches was utilized during the early establishment period. Even though mowing heights were kept as high as possible, the extent of root development may still have been limited and perhaps contributed to the plant’s inability to survive the very hot dry conditions experienced from late spring through mid-summer of 2006.
Because mowing is known to negatively impact turfgrass rooting, it may have been better to minimize or even eliminate mowing on this site and use an herbicide to manage potentially excessive weed competition early in the establishment period. This would have allowed the development of a deeper, more robust turfgrass root system and perhaps provided better tolerance, even survival, of the environmental stresses posed on this site. Hard fescue and sheep fescue are known to have very good to excellent drought tolerance and would be expected to survive and grow in relatively harsh conditions. However, all four of the fine fescue species/cultivars used in this study experienced difficulty in maintaining acceptable turfgrass density and growth where not partially protected by filtered shade from trees.
In addition to the mowing, there were relatively high levels of Canadian geese feeding on the lower two-thirds of most plots during the late summer and fall periods of 2006. Again, that kept plant heights very short, well below the three inch mowing height in some parts of the plots, and hence would likely had a negative impact on turfgrass rooting depth especially during the active root growth period of early to mid fall for our cool season turfgrasses. While all plots experienced at least some degree of geese feeding, it did appear to be less on the two tall fescue plots.
The seeded and sodded tall fescue plots performed remarkably well with respect to their ability to tolerate and recover from hot dry conditions. Also, there appeared to be little overwintering injury due to lack of hardiness; a problem previously limiting the use of tall fescues in this region. In addition, there did not appear to be any particular advantage of using tall fescue sod versus seeding tall fescue under a Futerra™ erosion control mat. Ratings on all characteristics were similar throughout the course of the study.
There are many instances where poor site conditions create extremely difficult conditions for establishing any type of vegetative cover, including turfgrass. Results and observations from this study indicate that the use of fine fescue turfgrass species as well as certain varieties of turf-type tall fescue under no-mow practices could make acceptable or better plant material choices than what is typically used for these conditions. While both survived quite well in partially shaded conditions, the slightly lower temperatures along with reduced sunlight intensity clearly benefited the survival and growth of the fine fescues to a greater extent than the turf-type tall fescues. Future projects should continue evaluating turf-type tall fescues and fine fescues in these difficult environments. In turn, this will continue to build the data base of successful turfgrass species and essential cultural practices needed to establish low maintenance turfgrasses on these difficult sites near shorelines.
Continue to the planning process for your 2009 garden. As you decide the plant materials you would like to have this season consider how you will obtain these plants. Some may not be readily available and you will need to start them from seed soon or orders should placed soon for seed and nursery stock to help ensure you get what you want. Many catalog suppliers have discounts or other incentives for those that order early.
As the days get longer and light intensity increases, consider starting to fertilize houseplants again. It is important to read and follow directions carefully. Different fertilizers have different concentrations of nutrients in them which can lead to different application rates. Also, fertilizer formulation is an important factor because that can influence how fast it dissipates, how readily the nutrients are available to the plants, and how often it should be applied. Again, take the time to read and then follow the directions. As light increases this time of year, so does the potential for photosynthesis and ultimately growth. It is important to recognize that fertilizer does not provide plants with energy, but building blocks for growth. These elements are assembled to build tissue for growth from the energy captured from light via photosynthesis. It is important not to overfertilize plants because buildup of unused fertilizer can damage plants.
Bring a preview of spring into your home with forced bulbs. If you haven’t potted some spring flowering bulbs for forcing yourself, they can readily be purchased from garden centers. Purchase potted bulbs that have not opened yet and keep them in a relatively cool spot in the house to help extend the impressive show.
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Happy gardening!
David C. Zlesak, Ph.D.
Editor
Extension Educator